                 FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


POLLINATOR STEWARDSHIP                     No. 13-72346
COUNCIL; AMERICAN HONEY
PRODUCERS ASSOCIATION;
NATIONAL HONEY BEE ADVISORY
BOARD; AMERICAN BEEKEEPING                  OPINION
FEDERATION; THOMAS R. SMITH;
BRET L. ADEE; JEFFERY S.
ANDERSON,
                       Petitioners,

                  v.

U.S. ENVIRONMENTAL PROTECTION
AGENCY; BOB PERCIASEPE, in his
official capacity as acting
administrator of the USEPA,
                          Respondents,

DOW AGROSCIENCES LLC,
          Respondent-Intervenor.


        On Petition for Review of an Order of the
           Environmental Protection Agency

                 Argued and Submitted
       April 14, 2015—San Francisco, California

                Filed September 10, 2015
2        POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

    Before: Mary M. Schroeder and N. Randy Smith, Circuit
        Judges and John A. Kronstadt,* District Judge.

                   Opinion by Judge Schroeder;
                 Concurrence by Judge N.R. Smith


                           SUMMARY**


        Federal Insecticide, Fungicide, and Rodenticide Act

    The panel vacated the Environmental Protection Agency’s
unconditional registration of sulfoxaflor, and remanded for
the EPA to obtain further studies and data regarding the
effects of sulfoxaflor on bees, as required by EPA
regulations.

    The Federal Insecticide, Fungicide, and Rodenticide Act
prohibits the use or sale of pesticides that lack approval and
registration by the EPA. Petitioners are commercial bee
keepers and bee keeping organizations, and they challenge
the EPA’s approval of insecticides containing sulfoxaflor,
which initial studies showed were highly toxic to bees.

    The panel held that because the EPA’s decision to
unconditionally register sulfoxaflor was based on flawed and
limited data, the EPA’s unconditional approval was not


    *
  The Honorable John A. Kronstadt, United States District Judge for the
Central District of California, sitting by designation.
  **
     This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.             3

supported by substantial evidence. The panel vacated the
EPA’s unconditional registration because given the
precariousness of bee populations, leaving the EPA’s
registration of sulfoxaflor in place risked more potential
environmental harm than vacating it.

     Concurring in the judgment, Judge N.R. Smith agreed
with the panel’s decision because he could not say the EPA
supported its decision with substantial evidence. He wrote
separately to ask the EPA to explain the analysis it conducted,
the data it reviewed, and how it relied on the data in making
its final decision.


                         COUNSEL

Janette K. Brimmer, Earthjustice, Seattle, Washington;
Gregory C. Loarie (argued), Earthjustice, San Francisco,
California, for Petitioners.

Robert G. Dreher, Acting Assistant Attorney General,
Environment & Natural Resources Division, Christina L.
Richmond and John Thomas H. Do (argued), Environmental
Defense Section, United States Department of Justice,
Washington, D.C.; Erin Koch, Of Counsel, Office of General
Counsel, United States Environmental Protection Agency,
Washington, D.C., for Respondents.

Christopher Landau, Kirkland & Ellis, LLP, Washington,
D.C.; David B. Weinberg (argued), William S. Consovoy,
Joseph S. Kakesh, and Craig G. Fansler, Wiley Rein, LLP,
Washington, D.C., for Respondent-Intervenor.
4   POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

George A. Kimbrell and Sylvia Shih-Yau Wu, Center for
Food Safety, San Francisco, California, for Amici Curiae
Center for Food Safety, Northeast Organic Farming
Association Interstate Council, Northeast Organic Farming
Association, Massachusetts Chapter, Inc., Northeast Organic
Farming Association of Rhode Island, Inc., Northeast Organic
Farming Association of New York, Inc., Maine Organic
Farmers and Gardeners Association; Defenders of Wildlife,
Friends of the Earth, Center for Environmental Health,
Conservation Law Foundation, Midwest Organic and
Sustainable Education Service, Beyond Pesticides, Pesticide
Action Network of North America, The Sierra Club, National
Family Farm Coalition, and American Bird Conservancy.


                        OPINION

SCHROEDER, Circuit Judge:

    The Federal Insecticide, Fungicide, and Rodenticide Act,
known as FIFRA, prohibits the use or sale of pesticides that
lack approval and registration by the Environmental
Protection Agency (“EPA”). 7 U.S.C. § 136a(a). The EPA
may deny an application for registration when “necessary to
prevent unreasonable adverse effects on the environment.”
Id. This case is a challenge to the EPA’s approval of
insecticides containing sulfoxaflor, which initial studies
showed were highly toxic to honey bees. Bees are essential
to pollinate important crops and in recent years have been
dying at alarming rates. Petitioners are commercial bee
keepers and bee keeping organizations.

    The EPA initially proposed to conditionally register
sulfoxaflor and requested additional studies to address gaps
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.              5

in the data regarding the pesticide’s effects on bees. A few
months later, however, the EPA unconditionally registered
the insecticides with certain mitigation measures and a
lowering of the maximum application rate. It did so without
obtaining any further studies. Because the EPA’s decision to
unconditionally register sulfoxaflor was based on flawed and
limited data, we conclude that the unconditional approval was
not supported by substantial evidence. We therefore vacate
the EPA’s registration of sulfoxaflor and remand.

                      BACKGROUND

    FIFRA prohibits growers from using or companies from
selling any pesticide that the EPA has not approved and
registered. 7 U.S.C. § 136a(a). FIFRA uses a “cost-benefit
analysis to ensure that there is no unreasonable risk created
for people or the environment from a pesticide.” Washington
Toxics Coal. v. EPA, 413 F.3d 1024, 1032 (9th Cir. 2005).
Specifically, FIFRA allows the EPA to deny an application
for registration of a pesticide to prevent “unreasonable
adverse effects.” 7 U.S.C. § 136a(a). “Unreasonable adverse
effects” is defined as “any unreasonable risk to man or the
environment, taking into account the economic, social, and
environmental costs and benefits of the use of [the]
pesticide.” 7 U.S.C. § 136(bb).

    In order to register a new pesticide, a manufacturer must
submit an application for registration, describing how the
pesticide will be used, the claims made of its benefits, the
ingredients, and a description of all tests and studies done and
the results thereof, concerning the product’s health, safety,
and environmental effects. 7 U.S.C. § 136a(c); Thomas v.
Union Carbide Agr. Products Co., 473 U.S. 568, 571 (1985).
The EPA may either “unconditionally” register a pesticide,
6   POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

7 U.S.C. § 136a(c)(5), or “conditionally” register it, id.
§ 136a(c)(7)(C). The EPA conditionally registers a pesticide
when there is insufficient data to evaluate the environmental
effects of a new pesticide, permitting the pesticide to be used
“for a period reasonably sufficient for the generation and
submission of required data.” 7 U.S.C. § 136a(7)(C).
Unconditional registration necessarily requires sufficient data
to evaluate the environmental risks.

   In 2010, Respondent-Intervenor Dow Agrosciences LLC
applied for approval of sulfoxaflor under 7 U.S.C.
§ 136a(c)(5). That provision of FIFRA states that the
administrator shall register a new pesticide if:

       (A) its composition is such as to warrant the
       proposed claims for it;

       (B) its labeling and other materials required to
       be submitted comply with the requirement of
       this subchapter;

       (C) it will perform its intended function
       without unreasonable adverse effects on the
       environment; and

       (D) when used in accordance with widespread
       and commonly recognized practices it will not
       generally cause unreasonable adverse effects
       on the environment.

7 U.S.C. § 136a(c)(5).

   Dow applied to register three different products, each
containing sulfoxaflor as the main/active ingredient.
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.               7

Sulfoxaflor is a new insecticide that targets a range of insects.
It acts on the same receptor in insects as does the class of
insecticides referred to as neonicotinoids, but its mechanism
is distinct from other neonicotinoids, so it is currently the
only member of a subclass of neonicotinoids called
sulfoximines. Some insects that are resistant to other
neonicotinoids are not resistant to sulfoxaflor because of the
unique mechanism sulfoxaflor uses. All neonicotinoids kill
insects by interfering with their central nervous system,
causing tremors, paralysis, and death. Neonicotinoids,
including sulfoxaflor, are “systemic” insecticides, which
means that they are sprayed onto plants, which then absorb
the chemicals and distribute them throughout the plant, into
the tissues, pollen, and nectar. Sulfoxaflor and other systemic
insecticides therefore kill insects in two different ways:
insects die when they come into contact with the pesticide, as
when they are sprayed with it, and also when they ingest the
plant which has absorbed the pesticide.

    Dow asked the EPA to approve sulfoxaflor for use on a
variety of different crops, including citrus, cotton, cucurbits,
fruiting vegetables, canola, strawberries, soybeans, wheat,
and many others. The maximum rate of application that Dow
proposed varied depending on the crop, with the highest rate
being 0.133 pounds of active ingredient per acre (“lb a.i./A”)
per application. The minimum number of days between
applications also varied by crop, ranging from 5 to 14 days.
The maximum yearly application rate of 0.266 pounds of
active ingredient per acre was consistent across all crops.

   As part of its registration application, Dow made a
number of claims regarding the benefits to using sulfoxaflor
over other comparable pesticides. These claims and the
support for them are not in the public record. The public
8   POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

record does indicate that a number of commenters to the
EPA’s proposed conditional registration decision made
similar claims regarding the need for and benefits of using
sulfoxaflor. Dow also submitted studies and data about the
effects of sulfoxaflor on various species, including bees.

    The EPA analyzed the studies submitted by Dow using a
new framework it had recently developed to better analyze
the risks to bees, in light of growing concerns about the rapid
decline in bee populations.

I. The Pollinator Risk Assessment Framework

    The new framework, called the Pollinator Risk
Assessment Framework, was developed through consultations
between the EPA, Canada’s Pest Management Regulatory
Agency, and California’s Department of Pesticide Regulation.
It was presented to the FIFRA Scientific Advocacy Panel in
2012 in the form of a document called a “White Paper.” The
framework explains it is intended to be iterative and to rely
on multiple lines of evidence to further refine and
characterize potential risk. It therefore establishes several
tiers of evaluation.

     The first “preliminary or screening-level” tier, Tier 1, is
intended to identify whether potential risks to bees exist. If
a risk to bees is identified in Tier 1 then the next tiers, Tier 2
and Tier 3, are intended to define when and where the risks
exist and their magnitude. Tiers 2 and 3 “attempt to refine
and/or characterize risk estimates to determine the conditions
of risk occurrence and, when relevant, to identify spatially-
and temporally-specific risks.”
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.           9

   A. Tier 1

    At Tier 1, the EPA compares the extent to which bees
would be exposed to a pesticide in the environment with the
doses at which that pesticide is toxic to bees. Specifically,
the EPA reviews studies to determine the “acute median
lethal dose” (or “LD50”) of a pesticide, meaning the dose at
which half of the individual bees tested die. See 40 C.F.R.
§ 152.3. The EPA looks at the acute median lethal dose for
both contact doses (i.e., bees sprayed directly with the
chemical) as well as oral doses (bees consuming nectar or
pollen contaminated with the chemical).

    Based on the studies Dow submitted as part of its
registration application, the EPA determined that the acute
median lethal contact dose of sulfoxaflor for bees was 0.13
micrograms of active ingredient per bee. The EPA also
determined that the acute median lethal oral dose of
sulfoxaflor for bees was 0.052 micrograms of active
ingredient per bee. These levels of acute median lethal dose
mean that sulfoxaflor is classified as “extremely toxic” to
honey bees.

    The framework then calls for the EPA to compare these
median lethal doses with the concentration of the pesticide
that would be expected in the environment, based on
characteristics of that pesticide as well as the proposed
application rate. For sulfoxaflor applied at the maximum
application rate Dow proposed, the expected environmental
concentration for oral consumption by bees was determined
to be 4.3 micrograms of active ingredient per bee. The
expected environmental concentration for contact exposure
for bees was determined to be 0.72 micrograms of active
ingredient per bee.
10 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

    The next step is for the EPA to divide the expected
environmental concentrations with the acute median lethal
doses to arrive at a figure it calls the “risk quotient,” or “RQ.”
The EPA has determined that risk quotients over 0.4 for bees
(called the “level of concern” or “LOC”) trigger a need for
further study, as a risk quotient of 0.4 represents a scenario
where 10% or more of bees in an environment would be
killed.

   The risk quotient for oral exposure to sulfoxaflor for bees
was measured at 83, while the risk quotient for contact
exposure to sulfoxaflor was measured at 2.8. Thus, both risk
quotients clearly exceeded 0.4, the level at which the EPA
expresses concerns serious enough to require further testing.

    Before proceeding to Tier 2, however, the EPA also
analyzed additional studies Dow had provided regarding
residue, or the amount of sulfoxaflor that manifests itself in
the pollen and nectar of sprayed crops, in order to refine the
risk analysis for oral exposure. Using those residue levels,
the EPA also separated out different risk quotients for
different types of bees (e.g., adult and larvae, and different
castes within adult bees such as worker, drone, and queen)
depending on their different consumption patterns.

    The new risk quotients for different types of bees ranged
from less than 0.8 to 5.7, all of which continued to exceed the
LOC of 0.4. However, the EPA identified several
shortcomings in the residue studies, that made it difficult to
determine whether the residue results were accurate and
suggested the results actually understated the risk. For
example, some data was collected several days after pesticide
application and at a rate lower than proposed.
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 11

   B. Tier 2

    Because the risk quotients, even with refinement,
continued to exceed the level of concern, the EPA proceeded
to Tier 2 of the risk assessment framework. Whereas the
framework’s Tier 1 analysis is based on studies and statistical
modeling of bees in the laboratory, Tier 2 and Tier 3 studies
are structured to evaluate the effects of an insecticide on bees
in the environment. And whereas the Tier 1 analysis focuses
on the effects of the insecticide on individual bees, Tier 2 and
Tier 3 analyses attempt to measure the effect on the colony as
a whole.

    Tier 2 studies are generally referred to as “semi-field
studies”; they consist of bees placed in a tunnel enclosure and
forced to feed on pesticide-treated crops. Because bees
interact with each other, feed each other, and transport and
consume food differently depending on their role within the
hive, semi-field studies attempt to better capture the effect
that a pesticide would have on the functioning of the entire
colony.

    Semi-field studies, nevertheless, have a number of
limitations. The bees are stressed by being put into a tunnel;
thus even in the control tunnels, where the bees are not fed
pesticide-treated food, they die at much higher rates than in
their normal environment. Because bees in the environment
feed on a variety of crops, some of which may be treated and
some of which may not, tunnel studies may overstate the
effects on nearby hives of spraying one crop. In addition, the
studies cannot last more than seven to ten days due to the
added stress bees incur in the tunnels. This means the studies
may not capture sublethal effects of insecticides that take
longer to manifest (i.e., effects that do not immediately kill
12 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

bees but adversely affect their ability to function in myriad
ways, leading to a long term decline in bee population).

    For its Tier 2 analysis Dow submitted six tunnel semi-
field studies. These studies were done at different times over
the course of several years, and varied widely in terms of
application rate, number of tunnels, times the study was
replicated, the timing of pesticide application, duration of
observation period, and the time of year at which the study
was conducted. Perhaps most significantly, all but one of the
studies used application rates substantially below the
maximum proposed by Dow, 0.133 pounds of active
ingredient per acre. The application rates used in five of the
six studies ranged from 0.006 to 0.088 pounds of active
ingredient per acre.

    The sixth study, “Ythier 2012,” had additional limitations.
Only two of the seven applications used the maximum
application rate of 0.134 pounds of active ingredient per acre.
The other five applications tested rates less than the
maximum proposed application rate. The Ythier 2012 study
used cotton as its test crop, which may have skewed its
results, as cotton is a sub-optimal source of pollen for honey
bees and the bees were therefore not able to maintain
sufficient stores of pollen during the study. Additionally, the
Ythier 2012 study was designed for quantifying the residue
of sulfoxaflor in the plant’s nectar and pollen, not for
studying the biological effects of sulfoxaflor on the bees;
thus, as the EPA’s own assessment explained, it provided
only “limited biological effects information.”

   After its Tier 2 analysis, the EPA concluded that
additional data was needed. The EPA found that the results
from the Tier 2 studies showed that, at the rates used
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 13

(generally 3–67% of the maximum application rate
proposed), the effects on adult bees were relatively short-
lived, lasting 3 days or less. But the EPA also concluded that,
because the majority of studies used a lower application rate
than the one Dow proposed, “[t]he direct effect of sulfoxaflor
on [measures of adult forager bee mortality, flight activity,
and behavioral abnormalities] at the maximum application
rate in the US is presently unknown.” Furthermore, due to
various limitations in all of the studies, the effect of
sulfoxaflor, when applied at the maximum proposed rate, on
both brood development and long-term colony health was
“inconclusive.”

    The EPA’s environmental risk assessment concluded that
additional studies were required, including “one or more Tier
2 semi-field tunnel studies conducted according to OECD 75
guidance.” “OECD” refers to the Organization for Economic
Coordination and Development, an international organization
that has developed protocols for honey bee semi-field tests.
In its regulations, the EPA has viewed the OECD protocols
favorably, explaining that they “can be used to develop data
necessary to meet the requirements [of FIFRA].” 40 C.F.R.
§ 158.70(d)(2). The record does not suggest that those
studies have ever been conducted.

II. The Initial, Proposed Conditional Registration

    Because of the gaps in data, the EPA declined to give
unconditional approval to sulfoxaflor. It proposed instead to
conditionally register sulfoxaflor while it collected additional
data. As part of its proposed conditional registration,
announced in January 2013, the EPA decided to lower the
maximum single application rate of sulfoxaflor from 0.133
pounds of active ingredient per acre to 0.09 pounds of active
14 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

ingredient per acre. The EPA also proposed some other
mitigation measures, including crop-specific restrictions on
spraying before or during bloom and suggested guidelines on
some labels regarding the best time to spray.

    To address the insufficiency of data, the EPA’s proposed
conditional registration required Dow to conduct and submit
the results of additional tests, specifically “a Tier 2 semi-field
study for assessing impacts on honey bee colony strength and
brood development in accordance with OECD-established
test guidelines” and “an additional residue study to address
the nature and magnitude of sulfoxaflor residues on a
pollinator-attractive crop (e.g., canola).” The EPA said that
these additional studies would resolve “any residual
uncertainty” regarding the effects of sulfoxaflor, and would
help it determine whether Dow’s requested maximum
application rate of 0.133 pounds per acre could be used in the
future.

    The EPA was concerned about the risk to bees during the
time it would take to do more studies. Nevertheless, in
addressing the risk, the EPA determined that sulfoxaflor
could be used while these studies were being performed,
because “sulfoxaflor applications will not result in a
catastrophic loss to brood during the time period required for
the conditional studies to be performed and assessed.”
(emphasis added).

III.    The Final Unconditional Registration

    Although the EPA announced its decision to propose
conditional registration of sulfoxaflor in January 2013,
pending receipt of additional data, less than seven months
later, on May 6, the EPA decided, to “unconditionally”
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 15

register sulfoxaflor. It did so even though the record reveals
that Dow never completed the requested additional studies.
The EPA acknowledged the insufficiency of the data to
support unconditional registration at the maximum rate Dow
had sought, but gave its approval to usage under modified
circumstances.

    The EPA justified its new unconditional registration
decision by the addition of various mitigation measures:
lower maximum application rate of 0.09 pounds of active
ingredient per acre, longer minimum intervals between
applications, and certain crop-specific restrictions on spraying
before or during bloom. The record does not indicate the
EPA had ever received any additional data on the effect of
such measures. Moreover, the restrictions on spraying during
bloom could not apply to continuously blooming crops such
as cotton and citrus. For these crops, the EPA required added
warning language on the label. For example, the label for
cucurbits, strawberries and citrus was mandated to contain the
following statement:

       Advisory Pollinator Statement: Notifying
       known beekeepers within 1 mile of the
       treatment area 48 hours before the product is
       applied will allow them to take additional
       steps to protect their bees. Also, limiting
       application to times when managed bees and
       native pollinators are least active, e.g., before
       7 am or after 7 pm local time or when the
       temperature is below 55E F at the site of
       application, will minimize risk to bees.

    The EPA acknowledged that it had classified sulfoxaflor
as “very highly toxic” to bees. And it acknowledged that the
16 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

existing studies were inconclusive as to risks to brood
development and colony strength. Although the EPA argued
that all of the studies provided relevant data, as noted, only
two of the six semi-field studies studied the effects of
sulfoxaflor at 0.09 pounds of active ingredient per acre (the
application rate that the EPA ultimately unconditionally
approved). The EPA nevertheless concluded that while there
exists “potential hazard to bees from exposure to sulfoxaflor,”
that hazard will be appropriately mitigated by “reduced
application rates, increased minimum application intervals,
and the pollinator-related labeling mitigation.”

    The EPA could not give unconditional registration if
usage would result in unreasonable adverse environmental
effects. The EPA concluded that applying sulfoxaflor
according to the label would not cause “unreasonable adverse
effects” on bees, and that “the benefits of [sulfoxaflor]
compared to the registered alternatives, as well as
[sulfoxaflor’s] ability to control problematic target pests”
outweighed the costs and therefore justified registration.
Overall, despite its earlier refusal to grant unconditional
registration pending additional studies, and despite the lack
of any meaningful study of the effects of the mitigation
measures, the EPA concluded that no additional data on
sulfoxaflor was required.

    After the EPA announced its final decision to
unconditionally register sulfoxaflor, petitioners filed a
petition for review with this court, claiming that the EPA’s
decision was not supported by substantial evidence in the
record as a whole. Dow and the EPA defend the registration
decision by arguing that, while the studies submitted by Dow
had limitations, the EPA was nonetheless able to glean
sufficient useful data from the studies to support its
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 17

registration decision, and that the EPA retains the flexibility
to determine the type of data needed to support registration in
each case. The EPA thus maintains that the record contains
sufficient evidence to support its unconditional registration at
the lower maximum rate.

                       DISCUSSION

     Under FIFRA, a court reviewing the EPA’s decision to
register a new insecticide shall uphold the EPA’s decision “if
it is supported by substantial evidence when considered on
the record as a whole.” 7 U.S.C. § 136n(b).

     We have jurisdiction under 7 U.S.C. § 136n(b). All the
parties agree that the studies underlying the EPA’s Tier 2
analyses had serious limitations. No additional studies were
submitted to evaluate the mitigation measures the EPA added
in its unconditional registration. We cannot conclude that the
unconditional registration is supported by the record as a
whole.

    With respect to remedy, we conclude we must vacate the
registration and remand to the agency.

I. Limitations in Tier 2 Studies

    The EPA’s regulations require the EPA to “Review[] all
relevant data in [its] possession” and to “determine[] that no
additional data are necessary” to make determinations of no
unreasonable adverse effects. 40 C.F.R. § 152.112(b)–(c).
The regulations also require “field testing for pollinators” to
be submitted as part of an application for registration if data
from other sources indicates a risk to honey bees. 40 C.F.R.
§ 158.630(d) and (e) n.25. All parties agree that, because
18 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

some data indicated a potential risk of adverse effects on
honey bee colonies, Dow was required to submit pollinator
field testing. In the White Paper addressing the new tiered
risk assessment framework for pollinators, the framework
drafters noted that while the requirement of “field testing for
pollinators” in 40 C.F.R. § 158.630 is general, semi-field
studies would satisfy that requirement.

    What data Dow submitted did not support approval of
sulfoxaflor at either the proposed maximum rate of 0.133
pounds of active ingredient per acre or the reduced maximum
rate of 0.09 pounds of active ingredient. In its original
conditional registration decision, the EPA had required
additional testing per “OECD guidance.” The record reveals
a number of deficiencies in Dow’s submitted semi-field
studies, most of which did not conform to OECD guidelines.
Although the EPA’s regulations do not mandate that studies
be performed in accordance with OECD guidelines, the
regulations state that studies done in accordance with OECD
protocol will suffice to meet the data requirements of FIFRA.
40 C.F.R. § 158.70(d)(2).

    Some of the deficiencies in Dow’s submitted studies were
unrelated to the fact that these studies did not comply with
OECD guidelines. Such deficiencies included limitations
inherent in the tunnel study design, such as the fact that bees
undergo significant stress when placed in a tunnel, and some
limitations related to the fact that the application rates used
were generally much lower than the maximum proposed
application rate. Some of the limitations would have been
ameliorated, however, had the studies conformed with OECD
guidance. For example, proper controls could have been
used, the studies could have been replicated more times, and
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 19

the bees could have been observed for a longer period of time
after being removed from the tunnels.

     One of the problems the EPA originally identified with
the Tier 2 studies was that only one of the studies used the
proposed maximum application rate, 0.133 pounds per acre,
and that study, Ythier 2012, was designed for quantifying
residue, not studying biological effects. Yet, at the lower rate
that the EPA approved, 0.09 pounds per acre, the studies
provided only slightly more data about the effects of
application. Portions of only two different studies provided
data regarding the effects of sulfoxaflor at the maximum
application rate of 0.09 pounds per acre: Ythier 2012 used an
application rate at or above 0.089 pounds per acre for four of
its seven applications. Hecht-Rost 2009 used an application
rate of 0.088 pounds per acre as one of its five applications.

    The Ythier 2012 study, because it was designed to
quantify plant residues, not biological effects, had other
limitations. It did not assess forager mortality, flight
intensity, forager behavior, or reference toxicant effects
(meaning the effect of sulfoxaflor as compared to known
toxic chemicals on control tunnels), and it did not include any
concurrent controls for interpreting biological effects or
brood development. These were noted in the EPA’s
environmental assessment.

    Hecht-Rost 2009 also had a number of limitations: there
was an infestation of a pest, Varroa mite, which can kill
honey bee colonies; there was a long pre-exposure period in
the tunnels of 11 days, which, given that bees are stressed by
being in tunnels, compromises the data; the colonies varied
widely between the different tunnels; there was a short
observation period of only 7 days; and there were few larvae
20 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

in the tunnels. Furthermore, Hecht-Rost 2009 included no
observation after the hives were removed from the tunnels.
And only one of the five applications provided data about an
application rate around 0.09 pounds per acre.

    Moreover, all of the studies, regardless of application rate,
suffered from an additional significant flaw: they provided
inconclusive or insufficient data on the effects of sulfoxaflor
on brood development and long-term colony health. Because
the honey bee colony is an interdependent “superorganism,”
the effect of an insecticide on one type of bee can ripple
through the hive. The two studies that provided the best data
for evaluating the effects on brood development, Schmitzer
2011a and 2011b, used application rates less than half of the
EPA’s new maximum rate of 0.09 pounds per acre. In these
two studies, the measurements for brood termination rate (the
number of brood that fail to develop through to emergence)
in the control tunnels was quite high, with 56% and 65% of
the brood failing to survive. By comparison, other studies
done according to OECD Guideline 75 reported brood
termination control rates of 8–43% in five control studies,
with three of the five controls reporting high brood
termination rates only because of poor weather.

     Because the brood failed to emerge at high rates even in
the control tunnels in the Schmitzer studies, the controls were
not suitable for comparison with the brood termination rates
of the tunnels treated with sulfoxaflor; thus, there was
inconclusive data as to the effect of sulfoxaflor on brood
termination rate. Accordingly, even these two studies reveal
little about the effect of sulfoxaflor on brood development,
both due to the low application rates used and due to
problems with the control tunnels that caused high brood
losses.
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 21

    In addition, all of the semi-field studies provided limited
information about longer term effects on colony strength.
The three studies with valid controls that studied colony
strength all used application rates of about half the new
maximum application rate. The studies that did not have
valid controls measured colony strength before and after
application and did not discern a measurable decline in
colony strength; however, these studies measured colony
health over a relatively short time period, between 7 and 17
days after sulfoxaflor treatment. The EPA assessment
acknowledged that different negative effects could appear on
the hive-level over a longer time period: for example, the
death of foraging bees that occurs immediately after
sulfoxaflor is sprayed might lead to premature recruitment of
hive bees into the forager work force.

    It was on the basis of all of these deficiencies and others
it noted, that the EPA in January 2013 concluded that it
needed additional studies regarding the effect on brood
development and long-term colony strength. That was when
the EPA decided to grant sulfoxaflor only conditional
registration.

    Though the EPA specified in January that the additional
studies were necessary to evaluate whether sulfoxaflor could
ever be used at the maximum proposed application rate of
0.133 pounds of active ingredient per acre, and unconditional
approval in May 2013 was for a lower application rate, the
limitations of the data regarding brood development and long-
term colony strength exist even with the lowered application
rate of 0.09 pounds per acre. By the EPA’s own reckoning,
the data was insufficient to evaluate the effect of sulfoxaflor
on brood development and long-term colony strength. The
22 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

decisions are not consistent.        The later, unconditional
approval lacks support.

    In addition to needing studies on brood development and
long-term colony strength, it is clear that the EPA was
lacking sufficient data on the impact of sulfoxaflor generally
even at the reduced application rate of 0.09 pounds of active
ingredient per acre. The EPA had only portions of two
studies evaluating the effects of sulfoxaflor at that rate. And
the EPA also recognized in its proposed conditional
registration that it needed more studies regarding the residue
of sulfoxaflor that appears in nectar and pollen in a crop that
is pollinator-attractive, such as canola. On the basis of the
studies submitted, the EPA lacked substantial evidence to
support its conclusions that application of sulfoxaflor at a rate
of 0.09 pounds per acre would not have an unreasonable
adverse effect on the environment.

    The EPA and Dow argue that since the studies are
inconclusive as to the risks of sulfoxaflor for bees, the studies
affirmatively prove that sulfoxaflor does not cause
unreasonable adverse effects on bees. Neither logic nor
precedent can sustain this position. We have previously held
that an agency cannot rely on ambiguous studies as evidence
of a conclusion that the studies do not support. See Tucson
Herpetological Soc. v. Salazar, 566 F.3d 870, 879 (9th Cir.
2009) (finding that the Secretary of the Interior erred when he
affirmatively relied on ambiguous and inconclusive studies to
support a conclusion). The limitations of the underlying data
in this case mean that no such conclusion can be reached.

    The EPA also argues that Tier 2 studies are only required
when analysis at the Tier 1 phase shows measurements above
the level of concern and, at the lower application rate of 0.09
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 23

pounds of active ingredient per acre, few of the residue
measurements were high enough to trigger the acute level of
concern. Thus, the EPA asks us to conclude the showing was
“close enough” so as not to trigger the requirement for Tier
2 studies. The EPA therefore contends that it is irrelevant
that the Tier 2 studies are severely flawed.

    This argument just does not fly. It is true that, at the
lower rate of 0.09 pounds per acre, only 2 of the 66 nectar
measurements and 1 of the 66 pollen measurements in the
Ythier 2012 study were above the level of concern. And only
1 of the nectar measurements in the other residue studies
(MRIDs 48476601, 48445806, 48755601) was above the
level of concern. It may well be true, as the EPA argues, that
its definition of the “level of concern” is inherently
conservative. But at least some of the measurements do
exceed the level of concern, and where data indicates a
potential risk to pollinators, the EPA’s regulations mandate
pollinator field testing. 40 C.F.R. § 158.630(d) and (e) n.25
(table showing data requirements for nontarget terrestrial and
aquatic organisms, including honey bees). Moreover, the
EPA’s assessment noted significant shortcomings in the
residue studies which created uncertainty in the extrapolation
of the results and which may have understated the risk. The
EPA acted in accordance with its regulations and common
sense in proceeding to Tier 2.

    We have previously held that we cannot allow the EPA to
avoid its own regulations when actual measurements trigger
risk concerns, even where the measurements were “in the
neighborhood” of measurements that would not trigger such
concern. We have said such an argument may be “well taken
as a practical matter” but is “irrelevant as a legal matter.” See
Natural Res. Def. Council v. EPA, 735 F.3d 873, 883–84 (9th
24 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

Cir. 2013) (holding that, where risk concern was triggered by
a measurement less than or equal to 1,000, and one of four
treatments measured exactly 1,000, the EPA could not argue
that the risk concern was not triggered). The EPA had
similarly argued in that case that its calculations were based
on very conservative assumptions, so a risk estimate that was
“close” to the threshold was close enough. Id. We rejected
that argument, holding that we cannot “revise EPA’s
assumptions, alter its rule of decision, or perform our own
risk assessment.” Id.

    The same is true here. The EPA chose to set its level of
concern at a measurement it now feels is overly conservative,
but a court cannot alter the agency’s own rule. And because
the EPA set its level of concern accordingly, and because at
least some of the residue measurements with the lower
application rate of 0.09 pounds per acre still triggered the
acute level of concern, pollinator field testing was required.
That requirement cannot be met by portions of two studies
which are limited in a variety of ways, particularly as regards
brood development and long-term colony strength – and
particularly given that the EPA itself recognized those
limitations.

    “It is well-established that an agency’s action must be
upheld, if at all, on the basis articulated by the agency itself.”
Motor Vehicle Mfrs. Ass’n of the U.S., Inc. v. State Farm Mut.
Auto. Ins. Co., 463 U.S. 29, 50 (1983) (internal citation
omitted). The EPA’s basis for unconditionally registering
sulfoxaflor in the absence of sufficient data documenting the
risk to bees does not hold up under its own rationale.
Without sufficient data, the EPA has no real idea whether
sulfoxaflor will cause unreasonable adverse effects on bees,
as prohibited by FIFRA. Accordingly, the EPA’s decision to
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 25

register sulfoxaflor was not supported by substantial
evidence.

    The matter must be remanded to the agency. We need not
reach the other claims of error raised by petitioners.

II. The Remedy

    The remaining issue is whether to vacate the registration
or remand while leaving the registration in place. We order
remand without vacatur only in “limited circumstances.” Cal.
Cmtys. Against Toxics v. EPA, 688 F.3d 989, 994 (9th Cir.
2012). We leave an invalid rule in place only “when equity
demands” that we do so. Idaho Farm Bureau Fed’n v.
Babbitt, 58 F.3d 1392, 1405 (9th Cir. 1995). When
determining whether to leave an agency action in place on
remand, we weigh the seriousness of the agency’s errors
against “the disruptive consequences of an interim change
that may itself be changed.” Cal. Cmtys. Against Toxics,
688 F.3d at 992 (quoting Allied-Signal, Inc. v. U.S. Nuclear
Regulatory Comm’n, 988 F.2d 146, 150–51 (D.C. Cir. 1993)).

    When deciding whether to vacate rulings by the EPA, we
consider whether vacating a faulty rule could result in
possible environmental harm, and we have chosen to leave a
rule in place when vacating would risk such harm. See, e.g.,
Idaho Farm Bureau Fed’n, 58 F.3d at 1405–06 (choosing not
to vacate because setting aside listing of snail species as
endangered would risk potential extinction of that species);
Cal .Cmtys. Against Toxics, 688 F.3d at 994 (remanding
without vacating because vacating could lead to air pollution,
undermining the goals of the Clean Air Act). We have also
looked at whether the agency would likely be able to offer
better reasoning or whether by complying with procedural
26 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

rules, it could adopt the same rule on remand, or whether
such fundamental flaws in the agency’s decision make it
unlikely that the same rule would be adopted on remand.
Compare Allied-Signal, 988 F.2d at 151 (declining to vacate
because there was “at least a serious possibility that the
[agency would] be able to substantiate its decision on
remand”), with North Carolina v. EPA, 531 F.3d 896, 200
(9th Cir. 2008) (concluding that the EPA’s rule “must” be
vacated because “fundamental flaws” prevented the EPA
from promulgating the same rule on remand).

    In this case, given the precariousness of bee populations,
leaving the EPA’s registration of sulfoxaflor in place risks
more potential environmental harm than vacating it.
Moreover, on remand, a different result may be reached.
Once the EPA obtains adequate Tier 2 studies, it may
conclude that a lower maximum application rate of
sulfoxaflor is warranted, or that sulfoxaflor cannot be
registered at all because of its effects on brood development
and long-term colony strength.

    We therefore vacate the EPA’s unconditional registration
of sulfoxaflor and remand for the EPA to obtain further
studies and data regarding the effects of sulfoxaflor on bees,
as required by EPA regulations.

   VACATED and REMANDED.

   Costs are awarded to the Petitioners.
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 27

N.R. SMITH, Circuit Judge, concurring in the judgment:

    I agree with the panel’s decision. The EPA’s
unconditional registration of sulfoxaflor should be vacated,
and the case should be remanded to the EPA. I cannot say the
EPA supported its decision with substantial evidence.
However, I write separately to provide an alternate
perspective.

    FIFRA has its own standard of review. Under FIFRA, a
reviewing court must sustain a pesticide registration if the
registration “is supported by substantial evidence when
considered on the record as a whole.” 7 U.S.C. § 136n(b).
“Substantial evidence means more than a mere scintilla but
less than a preponderance; it is such relevant evidence as a
reasonable mind might accept as adequate to support a
conclusion.” Nat. Res. Def. Council v. EPA, 735 F.3d 873,
877 (9th Cir. 2013) (quoting Vasquez v. Astrue, 572 F.3d 586,
591 (9th Cir. 2009)). The standard is “relatively deferential to
the agency factfinder,” but must still be “searching and
careful, subjecting the agency’s decision to close judicial
scrutiny.” Containerfreight Corp. v. United States, 752 F.2d
419, 422 (9th Cir. 1985) (internal quotation marks omitted).

    The substantial evidence standard affords an agency less
deference than the arbitrary and capricious standard. See
Universal Camera Corp. v. Nat’l Labor Relations Bd.,
340 U.S. 474, 477 (1951); Union Oil Co. of Cal. v. Fed.
Power Comm’n, 542 F.2d 1036, 1040–41 (9th Cir. 1976)
(explaining that we view the substantial evidence standard as
allowing greater scrutiny than the arbitrary and capricious
standard). Therefore, if the EPA’s pesticide registration is
arbitrary and capricious, the EPA cannot show it was
supported by substantial evidence.
28 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

    Under the arbitrary and capricious standard, a reviewing
court must not “substitute its judgment for that of the
agency.” Motor Vehicle Mfrs. Ass’n of U.S. v. State Farm
Mut. Auto. Ins., 463 U.S. 29, 43 (1983). In addition, a court’s
deference must be at its highest when examining factual
disputes that “implicate[] substantial agency expertise.”
Marsh v. Or. Nat. Res. Council, 490 U.S. 360, 376–77
(1989); Balt. Gas & Elec. Co. v. Nat. Res. Def. Council, Inc.,
462 U.S. 87, 103 (1983); see also Kleppe v. Sierra Club,
427 U.S. 390, 412 (1976) (“Resolving these issues requires a
high level of technical expertise and is properly left to the
informed discretion of the responsible federal agencies.”). We
discussed this deference at length in our en banc decision
Lands Council v. McNair, 537 F.3d 981 (9th Cir. 2008) (en
banc), rev’d on other grounds by Winter v. Nat. Res. Def.
Council, Inc., 555 U.S. 7 (2008). In Lands Council, we
explained that it “is not a proper role for a federal appellate
court” to “act as a panel of scientists that instructs [an
agency] how to validate its hypotheses . . . , chooses among
scientific studies . . . , and orders the agency to explain every
possible scientific uncertainty.” Id. at 988. Rather, the agency
“must have discretion to rely on the reasonable opinions of its
own qualified experts even if . . . a court might find contrary
views more persuasive.” Id. at 1000 (quoting Marsh, 490 U.S.
at 378). A court must even “uphold a decision of less than
ideal clarity if the agency’s path may reasonably be
discerned.” State Farm, 463 U.S. at 43 (quoting Bowman
Transp. Inc. v. Arkansas-Best Freight Sys., 419 U.S. 281, 286
(1974)).

    This paints the picture of a low hurdle for the EPA, and
indeed in most cases, I find an agency meets its burden with
the evidence in the record under both the arbitrary and
capricious standard and the substantial evidence standard.
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 29

However, although low, the hurdle exists for a reason, and the
EPA cannot simply walk around it. “[T]he agency must, at a
minimum, support its conclusions with studies that the
agency deems reliable.” N. Plains Res. Council, Inc. v.
Surface Transp. Bd., 668 F.3d 1067, 1075 (9th Cir. 2011)
(citing Lands Council, 537 F.3d at 994). And “the agency
must examine the relevant data and articulate a satisfactory
explanation for its action, including a ‘rational connection
between the facts found and the choice made.’” State Farm,
463 U.S. at 43 (quoting Burlington Truck Lines v. United
States, 371 U.S. 156, 168 (1962)).

    The EPA’s procedure and cursory explanations in this
case suggest the EPA has not met even the lower bar of the
arbitrary and capricious standard, much less the substantial
evidence standard. The EPA has shown that it analyzed
studies of sulfoxaflor, but not that it deems those studies
reliable. The EPA has shown that it reviewed data, but not
that its decision is rationally connected to the data. The EPA
has not “articulate[d] a satisfactory explanation for its action”
or provided an adequate basis for us to reasonably discern the
EPA’s path. Id. at 43. I do not ask the EPA to “explain every
possible scientific uncertainty” or instruct the EPA how to
improve its analysis. See Lands Council, 537 F.3d at 988. I
simply ask the EPA to explain the analysis it conducted, the
data it reviewed, and how the EPA relied on the data in
making its final decision. Currently, the EPA’s interesting
choice of procedure and lack of explanation regarding its
analysis call into question the connection between the cited
data and the final decision.
30 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

I. Procedure

    The EPA’s procedure causes me to doubt whether the
EPA adequately analyzed the effects of unconditionally
registering sulfoxaflor and whether the EPA could have
acquired substantial evidence on those effects. Without
reiterating all the facts set out in the majority opinion, I will
provide a brief timeline of the EPA’s relevant actions
concerning sulfoxaflor registration.

    The EPA first sought to determine the direct effects of
sulfoxaflor on honey bees when applied at Dow’s proposed
maximum application rate of 0.133 pounds of active
ingredient per acre (lbs a.i./A). The EPA uses a Tier 1 screen
to identify pesticides that do not pose any risk to pollinators.
The Tier 1 method is favored because “it is easy to use,
requires few input parameters, and takes little time to
complete.” Sulfoxaflor failed the Tier 1 screen with risk
quotients that far exceeded the level of concern. The EPA
then refined its Tier 1 study to use pesticide residue data
specific to sulfoxaflor and reran the Tier 1 test. Although
inefficient, the refined Tier 1 test can “provide valuable
information that may be used to characterize the risk of a
chemical to honey bees.” Again, sulfoxaflor failed the screen.
The risk quotients for honey bees at every life stage and in
every caste except the queen exceeded the 0.4 level of
concern. No risk quotient was calculated for the queen. Tier
1 produces “reasonably conservative” estimates of pesticide
exposure to bees, meaning the actual exposure should be less.
Nonetheless, the EPA determined that risk to honey bee
colonies could not be precluded.

    Pursuant to procedural guidelines when the EPA
identifies risks during a refined Tier 1 screen, the EPA must
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 31

identify and evaluate risk mitigation options, conduct a Tier
2 assessment, or do both. The EPA conducted a Tier 2
assessment. Tier 2 assessments are used to “obtain pesticide
specific, empirically-based exposure data that potentially
represent doses received by bees.” Unlike the quantitative
Tier 1 studies, risks identified in Tier 2 assessments are
described qualitatively. EPA’s Tier 2 assessments still
purported to study application rates of 0.133 lbs a.i./A.
However, only one of the six tunnel semi-field studies
submitted by Dow for Tier 2 assessment used that application
rate. The remaining studies tested application rates of 0.089
lbs a.i./A or less.

     The EPA’s conclusions from the Tier 2 studies were
tepid. The results corresponded with three categories: brood
development, direct effect, and colony strength. Of brood
development, the EPA stated: “Taken as a whole and in
consideration of their respective limitations, the results from
the six [Tier 2] tunnel studies are unable to conclusively
demonstrate whether sulfoxaflor applications adversely
impact brood development, even at the lower application
rates used.” Regarding direct effects, the EPA stated it did not
know what direct effect sulfoxaflor had on honey bees when
applied at the maximum application rate of 0.133 lbs a.i./A.
Instead, the EPA’s analysis of direct effects and colony
strength pertained only to the lower application rates (0.089
or less). The EPA concluded that “direct effects of sulfoxaflor
on adult forager bee[s were] . . . relatively short-lived, lasting
three days or less.” For colony strength, the EPA concluded
that the effects of sulfoxaflor were “either not apparent or
modest at most.”

    The EPA was critical of the six studies it analyzed at Tier
2. In speaking of sulfoxaflor’s effects on the environment as
32 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

a whole, the EPA stated that its “primary uncertainty” was
the “lack of a reliable Tier 2 semi-field study for assessing
impacts on honey bee colony strength and brood development
in accordance with OECD-established test guidelines.” The
EPA also noted that Dow’s studies only tested sulfoxaflor
with cotton, so “additional data on the nature and magnitude
of sulfoxaflor residues in one or more pollinator-attractive
crops would be needed.”

     After the Tier 2 assessments were complete, the EPA
proposed conditionally registering sulfoxaflor at a reduced
rate of 0.09 lbs a.i./A. In its proposed conditional registration,
the EPA said nothing about later registering sulfoxaflor
unconditionally at 0.09 lbs a.i./A. Rather, the EPA stated it
was registering sulfoxaflor conditionally only to provide the
EPA time to obtain data “resolv[ing] any residual uncertainty
on the potential effects of sulfoxaflor applications on brood
development and long-term colony health at the maximum
application rate initially proposed . . . (0.133 lbs [a.i/A]).”
The EPA determined that this additional data was
“necessary,” because there was “no conclusive evidence to
rule out long-term and more subtle brood impacts” caused by
sulfoxaflor. Regarding the lower application rate of 0.09 lbs
a.i./A, the EPA said only that the data indicated “sulfoxaflor
applications [would] not result in a catastrophic loss to brood
during the time period required for the conditional studies to
be performed and assessed.” The EPA received public
comment concerning the proposed conditional registration.
The EPA did not conduct any additional studies.

    Ultimately, the EPA neither granted the conditional
registration, for which it had received public comment, nor
the unconditional registration at 0.133 lbs a.i./A, for which it
had requested more data. Instead, the EPA granted
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 33

unconditional registration of sulfoxaflor at 0.09 lbs a.i./A
with numerous mitigation measures in place. The EPA
provided no opportunity for public comment on this
unconditional registration. However, the EPA did argue in
favor of the unconditional registration in its responses to
comments made by the public regarding the proposed
conditional registration. The EPA’s decision to register
sulfoxaflor unconditionally at 0.09 lbs a.i./A was not based on
new evidence. Rather it was based on a “review of the public
comments [on the conditional registration] and further
consideration of the database.”

    Based on this course of action, I have to wonder whether
the EPA actually obtained substantial evidence to support the
unconditional registration, shortly after it proposed the
conditional registration at that same rate. I am inclined to
believe the EPA instead decided to register sulfoxaflor
unconditionally in response to public pressure for the product
and attempted to support its decision retroactively with
studies it had previously found inadequate. Such action seems
capricious.

II. Explanation and Connection with Data

    Setting aside the EPA’s procedure, I still do not find that
the EPA supported its decision with a satisfactory explanation
that was rationally connected to the facts. Specifically, I
return to the EPA’s only clear statement explaining how it
arrived at its final decision: “After review of the public
comments and further consideration of the database, EPA has
concluded that an unconditional registration of sulfoxaflor,
with lowered application rates and other mitigation is
supported by available data and therefore the appropriate
regulatory decision.” The obvious questions in reading this
34 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

explanation are: (1) What “database”? and (2) What
“available data”? As the reviewing court, we must know the
answers to these questions. Yet, the EPA never explains
which data it included in its analysis.

    From the record, it seems certain that the EPA relied on
two sets of studies in making its final decision: the Tier 1 and
Tier 2 studies, which were conducted to determine whether
sulfoxaflor posed a risk to pollinators when applied at the
maximum application rate of 0.133 lbs a.i./A. In other words,
to unconditionally register sulfoxaflor at the maximum
application rate of 0.09 lbs a.i./A, the EPA relied on: (1) the
same Tier 1 studies that found sulfoxaflor’s risk of effects on
all life stages and castes of bees exceeded the level of
concern; and (2) the same Tier 2 studies that the EPA called
unreliable in the executive summary of its Environmental
Fate and Ecological Risk Assessment for Sulfoxaflor
Registration. To be fair, the EPA only found the Tier 2
studies unreliable as to data on colony strength and brood
development, not direct effects, but this does not lessen the
import of that critique. Nor did the EPA’s concerns disappear
after further review of the data. In its Decision Document, the
EPA wrote: “The effect of sulfoxaflor on brood development
is considered inconclusive due to the limitations associated
with the available studies . . . .” It continued: “[T]he design
of the Tier 2 studies does not enable the potential for long-
term effects [on colonies ]to be discounted completely.”

    The EPA has also provided us with no basis to determine
whether the original and refined Tier 1 studies or the six Tier
2 studies conformed with procedural standards. Not only has
the EPA done a poor job explaining how many tests were run
and what results followed, the EPA has also failed to provide
any comparison for us to determine what number of tests and
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 35

what range of results are acceptable. The only guidelines we
have to compare with the studies are the Organization for
Economic Cooperation and Development (OECD) guidelines
and the Office of Chemical Safety and Pollution Prevention
(OCSPP) guidelines. The EPA does not refer to either
guideline in describing the tests Dow conducted for
sulfoxaflor. Instead, the EPA acknowledges that the semi-
field studies submitted for Tier 2 did not comport with OECD
guidelines.

    The EPA argues that the EPA compensated for any
uncertainties in the Tier 1 and Tier 2 studies by adopting
mitigation measures. However, the EPA has not pointed to
any studies in the record showing that the EPA obtained data
on these mitigation measures. Nor does the EPA point to any
scientific studies or testimony in the record to support its
conclusions regarding the mitigation measures. See Lands
Council, 537 F.3d at 994.

    The EPA periodically refers to other data in the
“database” throughout its responses to public comments on
the proposed conditional registration, but none of these data
are explained in detail in the record. For instance, the EPA
refers to an “extensive analysis” of outside studies:

       The EPA conducted an extensive analysis of
       sulfoxaflor in collaboration with counterpart
       agencies in Canada and Australia. Scientists
       from all three authorities reviewed over 400
       studies, peer reviewed the primary evaluations
       conducted by their international colleagues,
       and communicated extensively on specific
       disciplines and issues. Additional EPA
36 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

        committees further reviewed the work done
        under the joint review project.

However, the EPA never explained the type of studies, how
they were conducted, or what results were obtained. Nor did
the EPA explain the outcome of its “extensive analysis,”
whether this analysis conformed with similar analyses for
other pesticides, or even how the EPA relied on the analysis
in making its final decision. The EPA certainly did not
explain any conclusions drawn from those studies or the
reasons it considered the studies to be reliable. See Lands
Council, 537 F.3d at 994.

    Of equal concern is the EPA’s reliance on data not in the
database. In its responses to public comments, the EPA
frequently cites lack of information as support for its final
decision. For instance, as evidence that sulfoxaflor will not
cause honey bee losses, the EPA states that it “has received
no reports [of] any sulfoxaflor-related incidents from the
2012 use under section 18 [emergency exemption]
authorizations. The state lead agencies informed EPA that
they were not asked to conduct any investigations and they
received no reports of adverse incidents.” And to bolster its
claims that sulfoxaflor is better than the pesticides sulfoxaflor
will replace, the EPA states that it is “not aware of any
information that would indicate that honey bee losses as a
result of exposure to sulfoxaflor would exceed or be any
different than those currently experienced with currently
registered insecticides.” The EPA cites no studies. It is worth
noting that the record contains evidence that the pesticides
sulfoxaflor would replace are more harmful to honey bees
than sulfoxaflor. However, the EPA has not pointed to this
evidence or demonstrated that it deems those studies reliable.
See N. Plains Res. Council, Inc., 668 F.3d at 1075. Nor has
    POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A. 37

the EPA provided a connection between the evidence in the
record and the EPA’s decision. State Farm, 463 U.S. at 43.

    Rather than citing to definitive information, the EPA
repeatedly dismisses data gaps and inconclusive evidence
with the explanation that the EPA “believed,” “had
knowledge,” or “relied on its best professional judgement.”
For instance, the EPA states: “Although statistical
weaknesses were documented for [the Tier 2 studies], the
Agency did not rely exclusively on statistical interpretation of
results in its risk findings. Rather, it relied on its best
professional judgment in evaluating the magnitude and
duration of effects from these studies.” The EPA also said:

       Although results from longer-term tunnel
       studies conducted at the current maximum
       single application rate of 0.086 lb a.i./A are
       desirable for confirming the results of the Tier
       1 risk assessment, the Agency believes that
       when results of Tier 1 and the proposed
       mitigation measures are considered, the
       existing limitations in the Tier 2 studies do
       not preclude registration of sulfoxaflor given
       the mitigation measures (such as reduced
       application rates and increased minimum
       spray intervals) that are included on the label
       and the benefits provided by sulfoxaflor.

Although the EPA certainly has authority to rely on its well-
founded beliefs, scientifically-derived knowledge, and
experience-driven professional judgment, it must support the
beliefs, knowledge, and judgment with evidence. We will
continue to grant agencies great deference, particularly in
cases, such as this one, which involve “substantial agency
38 POLLINATOR STEWARDSHIP COUNCIL V. U.S.E.P.A.

expertise.” Marsh, 490 U.S. at 376. However, there is a great
difference between ordering an agency to “explain every
possible scientific uncertainty,” Lands Council, 537 F.3d at
988, and requiring it to “articulate a satisfactory explanation
for its action” that is based on scientific data, State Farm,
463 U.S. at 43. Professional judgment and knowledge do not
meet the substantial evidence standard independent of data
and facts. Otherwise, the standard could always be met with
the sworn declaration of an expert stating the expert’s
experience alone made his opinion trustworthy. For me,
unless I am provided with evidence of the EPA’s basis for its
judgment and knowledge, I can only assume it acted with
none.
