                FOR PUBLICATION

   UNITED STATES COURT OF APPEALS
        FOR THE NINTH CIRCUIT


RICHARD STENGEL; MARY LOU                No. 10-17755
STENGEL,
             Plaintiffs-Appellants,         D.C. No.
                                         4:10-cv-00318-
                 v.                           RCC

MEDTRONIC INCORPORATED , a
foreign corporation,                        OPINION
                 Defendant-Appellee.


      Appeal from the United States District Court
               for the District of Arizona
       Raner C. Collins, District Judge, Presiding

                Argued and Submitted
     September 19, 2012—San Francisco, California

                Filed January 10, 2013

 Before: Alex Kozinski, Chief Judge; Sidney R. Thomas,
   Barry G. Silverman, Susan P. Graber, M. Margaret
McKeown, William A. Fletcher, Ronald M. Gould, Johnnie
 B. Rawlinson, Richard R. Clifton, N. Randy Smith, and
            Paul J. Watford, Circuit Judges.

            Opinion by Judge W. Fletcher;
            Concurrence by Judge Watford
2                 STENGEL V . MEDTRONIC, INC.

                           SUMMARY*


        Preemption / Medical Device Amendments

    The en banc court reversed the district court’s order
dismissing appellants’ state-law failure-to-warn claim as
preempted by the Medical Device Amendments to the Food,
Drug, and Cosmetic Act.

    The en banc court held that the Amendments do not
preempt a state-law claim for violating a state-law duty that
parallels a federal-law duty under the Amendments.
Therefore, the en banc court held that the Amendments did
not preempt, either expressly or impliedly, appellants’ state-
law failure-to-warn claim contained in the amended
complaint.

   Judge Watford concurred.          Judge Watford wrote
separately to provide additional thoughts as to why the state
law failure-to-warn claim alleged in the proposed amended
complaint was not preempted.


                            COUNSEL

Thomas G. Cotter, Haralson Miller Pitt Feldman &
McAnally, PLC, Tucson, Arizona, for Appellants.




  *
    This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                STENGEL V . MEDTRONIC, INC.                   3

Michael Kevin Brown, Lisa Marie Baird, Reed Smith, LLP,
Los Angeles, California; Timothy James Casey, Schmitt,
Schneck, Smyth & Herrod PC, Phoenix, Arizona, for
Appellee.

Elizabeth Jean Erwin, Office of the Washington Attorney
General, Seattle, Washington; Steve Bullock, Office of the
Montana Attorney General, Helena, Montana; Lawrence
Garth Wasden, Office of the Idaho Attorney General, Boise,
Idaho; Mary-Christine Sungaila, Snell & Wilmer LLP, Costa
Mesa, California; Kelly Harrison Dove, Snell & Wilmer LLP,
Las Vegas, Nevada; Jessica E. Yates, Snell & Wilmer LLP,
Denver, Colorado; Mary Massaron Ross, Plunkett Cooney,
Bloomfield Hills, Michigan; Alan Jay Lazarus and Sally F.
White, Drinker Biddle & Reath, LLP, San Francisco,
California; Hugh F. Young, Jr., Product Liability Advisory
Council, Inc., Reston, Virginia, for amici curiae.


                          OPINION

W. FLETCHER, Circuit Judge:

    Plaintiffs Richard and Mary Lou Stengel sued Medtronic
under state law when a medical device manufactured by
Medtronic rendered Richard permanently paraplegic.
Medtronic moved to dismiss the Stengels’ complaint,
contending that the Medical Device Amendments (“MDA”)
to the Food, Drug, and Cosmetic Act (“FDCA”) preempted
their state-law claims. The Stengels moved to amend their
complaint to add a new state-law negligence claim. That
claim alleged that Medtronic had violated a state-law duty of
care by failing to report known risks associated with use of its
medical device to the Food and Drug Administration
4               STENGEL V . MEDTRONIC, INC.

(“FDA”). The MDA required Medtronic to report those risks
to the FDA. Medtronic contended that the MDA also
preempted the Stengels’ new negligence claim.

    The district court held that the MDA preempted all of the
Stengels’ claims, including the new negligence claim.
Stengel v. Medtronic, Inc., No. CV 10-318-TUC-RCC, 2010
WL 4483970, at *3–4 (D. Ariz. Nov. 9, 2010). It denied the
Stengels’ motion to amend the complaint and dismissed their
suit under Federal Rule of Civil Procedure 12(b)(6). Id. The
Stengels appealed the denial of their motion to amend, as well
as denial of an evidentiary ruling. A panel of this court
affirmed over a dissent. 676 F.3d 1159 (9th Cir. 2012). We
granted rehearing en banc. 686 F.3d 1121 (9th Cir. 2012).

    The central question in this appeal is whether the MDA
preempts a state-law claim in which the state-law duty of care
“parallels” a federal-law duty imposed by the MDA. We
conclude that such a state-law claim is not preempted and
reverse the district court.

                       I. Background

    Congress enacted the MDA to extend the coverage of the
Food, Drug, and Cosmetic Act (“FDCA”) to medical devices.
See Riegel v. Medtronic, Inc., 552 U.S. 312, 315 (2008). The
MDA divides medical devices into three classes according to
user risk. Class I devices pose the least risk; Class III devices
pose the most. See id. at 316–17; see also 21 U.S.C.
§ 360c(a)(1). Class I devices are subject to “general controls”
such as labeling requirements. Id. § 360c(a)(1)(A); Riegel,
552 U.S. at 316. Class II devices are subject not only to
“general controls,” but also to “special controls” such as
“performance standards, postmarket surveillance, [and]
                STENGEL V . MEDTRONIC, INC.                     5

patient registries.” 21 U.S.C. § 360c(a)(1)(B); Riegel,
552 U.S. at 316–17. If a device cannot be determined to
provide a reasonable assurance of safety and effectiveness
under Class I or II controls and is either marketed as a life-
supporting device or may cause an unreasonable risk of
illness or injury, it is a Class III device. A Class III device is
subject to a pre-market approval process of the FDA.
21 U.S.C. § 360c(a)(1)(C); Riegel, 552 U.S. at 317. The
Medtronic pain pump and catheter that caused Richard
Stengel’s injury was a Class III device.

    The FDA’s pre-market approval process of a Class III
device is “rigorous.” Riegel, 552 U.S. at 317. The FDA
performs a risk-benefit assessment of the device and
determines the adequacy of the manufacturer’s proposed
label. Id. at 318. The FDA then denies, approves, or
approves with conditions on distribution, marketing, or sale.
See 21 U.S.C. § 360e(d); 21 C.F.R. § 814.82; see also Riegel,
552 U.S. at 318–19. Once the FDA approves a device, the
manufacturer is required to report any information that
reasonably suggests that the device (1) “[m]ay have caused or
contributed to a death or serious injury” or (2) “[h]as
malfunctioned” and that any recurring malfunction “would be
likely to cause or contribute to a death or serious injury.”
21 C.F.R. § 803.50(a); see 21 U.S.C. § 360i(a); see also
Riegel, 552 U.S. at 319.

    For purposes of this appeal, we assume that all allegations
in the Stengels’ proposed amended complaint are true.
Medtronic obtained pre-market approval of its SynchroMed
Pump & Infusion System in 1988. Medtronic obtained
supplemental pre-market approval for its SynchroMed EL
Pump and Catheter in 1999.
6              STENGEL V . MEDTRONIC, INC.

    On October 10, 2000, Richard Stengel had a SynchroMed
EL Pump and Catheter surgically implanted in his abdomen
to deliver pain relief medication directly into his spine. In
February 2005, Stengel collapsed at home. At the hospital,
he reported feeling heaviness and decreased sensation in his
right leg. He was diagnosed with ascending paralysis in his
lower body. A neurosurgeon removed the catheter, but
Stengel was left permanently paraplegic. Medtronic’s
medical device caused the paralysis.

     When it received FDA approval of its SynchroMed EL
Pump and Catheter, Medtronic was not aware of certain risks
associated with the device. Before Stengel was paralyzed,
however, Medtronic had become well aware of those risks but
had failed to inform the FDA, even though the MDA required
Medtronic to do so. The FDA discovered the risks, and
discovered that Medtronic already knew about them, when it
inspected a Medtronic facility in late 2006 and early 2007.
The FDA sent a Warning Letter to Medtronic in July 2007,
stating that Medtronic had “misbranded” its Class III device
by concealing known risks, in violation of 21 C.F.R.
§§ 803.50(a)(1), 806.10(a)(1). In response to the FDA’s
Warning Letter, Medtronic sent a Medical Device Correction
letter to doctors in January 2008. Medtronic recalled the
device in March 2008. This advice and recall came too late
to help Richard Stengel, who had been paralyzed in 2005.

                 II. Standards of Review

    We review de novo a district court’s legal conclusions
regarding the sufficiency of a complaint. Martinez v. Wells
Fargo Home Mortg., Inc., 598 F.3d 549, 553 (9th Cir. 2010).
We ordinarily review for abuse of discretion a denial of a
motion to amend a complaint. Alvarez v. Chevron Corp.,
               STENGEL V . MEDTRONIC, INC.                   7

656 F.3d 925, 931 (9th Cir. 2011). But here, where the
district court denied the motion to amend because of its
conclusion that the claim in the proposed complaint was
preempted as a matter of law, we review de novo. We have
appellate jurisdiction pursuant to 28 U.S.C. § 1291.

                       III. Discussion

    There is a presumption against federal preemption of state
laws that operate in traditional state domains. “In all
preemption cases, and particularly those in which Congress
has ‘legislated . . . in a field which the States have
traditionally occupied,’ we ‘start with the assumption that the
historic police powers of the States were not to be superseded
by the Federal Act unless that was the clear and manifest
purpose of Congress.’” Medtronic, Inc. v. Lohr, 518 U.S.
470, 485 (1996) (citations omitted) (omission in original).
Parties seeking to invalidate a state law based on preemption
“bear the considerable burden of overcoming ‘the starting
presumption that Congress does not intend to supplant state
law.’” De Buono v. NYSA-ILA Med. & Clinical Servs. Fund,
520 U.S. 806, 814 (1997) (citation omitted). “[T]he historic
police powers of the State include the regulation of health and
safety.” Id. “Throughout our history the several States have
exercised their police powers to protect the health and safety
of their citizens. Because these are ‘primarily, and
historically, . . . matter[s] of local concern, the ‘States
traditionally have had great latitude under their police powers
to legislate as to the protection of the lives, limbs, health,
comfort, and quiet of all persons.” Lohr, 518 U.S. at 475
(citations omitted) (omission and alteration in original).
8             STENGEL V . MEDTRONIC, INC.

   The MDA contains an explicit preemption clause that
provides as follows:

           Except as provided in subsection (b) of
       this section, no State or political subdivision
       of a State may establish or continue in effect
       with respect to a device intended for human
       use any requirement –

           (1) which is different from, or in
           addition to, any requirement
           applicable under this chapter to the
           device, and

           (2) which relates to the safety or
           effectiveness of the device or to any
           other matter included in a requirement
           applicable to the device under this
           chapter.

21 U.S.C. § 360k(a). Subsection (b) is not relevant to this
appeal.

    An implementing regulation provides:

          State or local requirements are preempted
       only when the Food and Drug Administration
       has established specific counterpart
       regulations or there are other specific
       requirements applicable to a particular device
       under the act, thereby making any existing
       divergent State or local requirements
       applicable to the device different from, or in
       addition to, the specific Food and Drug
                STENGEL V . MEDTRONIC, INC.                   9

       Administration requirements. . . . The
       following are examples of State or local
       requirements that are not regarded as
       preempted by [§ 360k]:

       ....

       (2) [Section 360k] does not preempt State or
       local requirements that are equal to, or
       substantially identical to, requirements
       imposed by or under the act.

21 C.F.R. § 808.1(d).

    The Supreme Court has decided three preemption cases
under the MDA. The rule that emerges from these cases is
that the MDA does not preempt a state-law claim for
violating a state-law duty that parallels a federal-law duty
under the MDA.

    The first case is Medtronic, Inc. v. Lohr, decided in 1996.
After Lora Lohr’s pacemaker failed, the Lohrs sued its
manufacturer, Medtronic, under state law for damages.
518 U.S. at 474, 480–81. The Lohrs’ complaint included
numerous state-law negligence claims, including a claim
alleging failure to warn the “plaintiff or her physicians of the
tendency of the pacemaker to fail, despite knowledge of other
earlier failures.” Id. at 481. Medtronic moved for summary
judgment, contending that all of the Lohrs’ state-law claims
were preempted. Id. The Court held that none of the Lohrs’
state-law claims was preempted. Id. at 503. It wrote:
“Nothing in § 360k denies Florida the right to provide a
traditional damages remedy for violations of common-law
10              STENGEL V . MEDTRONIC, INC.

duties when those duties parallel federal requirements.” Id.
at 495.

    Medtronic had argued that because the MDA provides no
damages remedy, it preempts states from providing such a
remedy, even for violations of parallel state-law duties. Id. at
486–87. In Part IV of his opinion, joined by three others,
Justice Stevens emphatically rejected Medtronic’s argument:

           An examination of the basic purpose of
       the legislation as well as its history entirely
       supports our rejection of Medtronic’s extreme
       position. The MDA was enacted “to provide
       for the safety and effectiveness of medical
       devices intended for human use.” . . . To the
       extent that Congress was concerned about
       protecting the industry, that intent was
       manifested primarily through fewer
       substantive requirements under the Act, not
       the pre-emption provision; furthermore, any
       such concern was far outweighed by concerns
       about the primary issue motivating the
       MDA’s enactment: the safety of those who
       use medical devices.

Id. at 490–491 (citation omitted). Justice Breyer did not
concur in Part IV, but specifically stated his reason for not
joining: “I do not join Part IV, which emphasizes the
differences between the MDA and the pre-emption statute at
issue in Cipollone [v. Liggett Group, Inc., 505 U.S. 504
(1992)], because those differences are not, in my view,
relevant in this action.” Id. at 508 (Breyer, J., concurring in
part and concurring in the judgment). Justice Breyer’s stated
               STENGEL V . MEDTRONIC, INC.                 11

reason for not joining Part IV did not include disagreement
with the passage quoted above.

     The Court held that the MDA did not preempt the Lohrs’
state-law claim alleging that Medtronic negligently had failed
to warn “plaintiff or her physicians” of the known dangers of
its pacemaker. The generality of the state-law duty to warn
was important to the Court’s analysis. The Court wrote:

       [T]he predicate for the failure to warn claim is
       the general duty to inform users and
       purchasers of potentially dangerous items of
       the risks involved in their use. Th[is] general
       obligation[] [is] no more a threat to federal
       requirements than would be a state-law duty
       to comply with local fire prevention
       regulations and zoning codes, or to use due
       care in the training and supervision of a work
       force.

Id. at 501–02. The state-law duties upon which the Lohrs
relied escape preemption “because their generality leaves
them outside the category of requirements that § 360k
envisioned to be ‘with respect to’ specific devices such as
pacemakers.” Id. at 502.

    The second case is Buckman Co. v. Plaintiffs’ Legal
Comm., 531 U.S. 341 (2001). The plaintiffs in Buckman
brought a state-law negligence suit for damages alleging
injuries resulting from orthopedic bone screws, a Class III
medical device. Id. at 343–44. Defendant Buckman was not
the manufacturer of the screws. Instead, it was a consulting
company that plaintiffs alleged had made fraudulent
misrepresentations to the FDA in the course of obtaining pre-
12             STENGEL V . MEDTRONIC, INC.

market approval for its client, the manufacturer. Id. at 343.
The Court characterized the plaintiffs’ state-law claims
against Buckman as “fraud-on-the-FDA claims.” Id. at 348.
It wrote that such claims

       conflict with, and are therefore impliedly pre-
       empted by, [the MDA]. The conflict stems
       from the fact that the federal statutory scheme
       amply empowers the FDA to punish and deter
       fraud against the Administration, and that this
       authority is used by the Administration to
       achieve a somewhat delicate balance of
       statutory objectives. The balance sought by
       the Administration can be skewed by allowing
       fraud-on-the-FDA claims under state tort law.

Id. (footnote omitted).

    The Court in Buckman distinguished Silkwood v. Kerr-
McGee Corp., 464 U.S. 238, 241, 258 (1984), in which it had
held that a state-law negligence cause of action allowing
punitive damages was not preempted by the Atomic Energy
Act. The Court wrote, “Silkwood’s claim was not based on
any sort of fraud-on-the-agency theory, but on traditional
state tort law principles of the duty of care owed by the
producer of plutonium fuel pins to an employee working in its
plant.” Buckman, 531 U.S. at 352. The Court also
distinguished Medtronic v. Lohr, in which the Lohrs’ “claims
arose from the manufacturer’s alleged failure to use
reasonable care” and had not been concerned with
wrongdoing during the FDA’s pre-market approval process.
Id. In contrast to the plaintiffs in Medtronic v. Lohr, the
plaintiffs in Buckman alleged no state-law claim and were
concerned exclusively with alleged fraud on the FDA that had
                 STENGEL V . MEDTRONIC, INC.                  13

occurred as part of that approval process. The Court found
that the pre-market approval process of a Class III device is
wholly federal—it “originates from, is governed by, and
terminates according to federal law.” Id. at 347–48. It
continued:

       In the present case, . . . the fraud claims exist
       solely by virtue of the FDCA disclosure
       requirements. Thus, although Medtronic [v.
       Lohr] can be read to allow certain state-law
       causes of action that parallel federal safety
       requirements, it does not and cannot stand for
       the proposition that any violation of the
       FDCA will support a state-law claim.

           In sum, were plaintiffs to maintain their
       fraud-on-the-agency claims here, they would
       not be relying on traditional state tort law . . . .

Id. at 352–53.

    The final case is Riegel v. Medtronic, Inc., 552 U.S. 312
(2008). Plaintiffs sued Medtronic for damages under state
law after an FDA-approved Class III catheter in the lead
plaintiff’s coronary artery ruptured. Id. at 320. The catheter
had been inflated to a higher pressure than recommended on
the FDA-approved label. Id. Plaintiffs alleged that the
catheter was defective under state law. Id. The Court held
that plaintiffs’ claims were expressly preempted by the MDA
because state law imposed a more stringent safety
requirement than federal law. Id. at 325. However, the Court
was careful to state that Medtronic v. Lohr remained good
law. It wrote:
14              STENGEL V . MEDTRONIC, INC.

           State requirements are pre-empted under
       the MDA only to the extent that they are
       “different from, or in addition to” the
       requirements imposed by federal law.
       § 360k(a)(1). Thus, § 360k does not prevent
       a State from providing a damages remedy for
       claims premised on a violation of FDA
       regulations; the state duties in such a case
       “parallel,” rather than add to, federal
       requirements. Lohr, 518 U.S., at 495[.]

Riegel, 552 U.S. at 330.

    There are three categories of preemption: express, field,
and conflict. See Indus. Truck Ass’n v. Henry, 125 F.3d 1305,
1309 (9th Cir. 1997). Field and conflict preemption are
subcategories of implied preemption. Though the Court did
not say so explicitly, it is clear that its decision in Lohr was
an across-the-board holding that there was no preemption
under any of the three categories. The Court framed the issue
without any qualification as to category of preemption: “The
question presented is whether [the MDA] pre-empts a state
common-law negligence action against the manufacturer of
an allegedly defective medical device.” Lohr, 518 U.S. at
474.

    During the course of its opinion, the Court addressed the
three categories. First, the Court held that there was no
express preemption. It wrote:

       [A]ny understanding of the scope of a pre-
       emption statute must rest primarily on “a fair
       understanding of congressional purpose.” . . .
       Congress’ intent, of course, primarily is
                STENGEL V . MEDTRONIC, INC.                  15

       discerned from the language of the pre-
       emption statute and the “statutory framework”
       surrounding it.

Id. at 485–86 (citation omitted) (emphasis in original).

    Second, the Court held there was no field preemption.
Justice Stevens wrote in Part IV:

       [Medtronic] argues that the plain language of
       the statute pre-empts any and all common-law
       claims brought by an injured plaintiff against
       a manufacturer of medical devices.

          Medtronic’s argument is not              only
       unpersuasive, it is implausible. . . .

       . . . Given the ambiguities in the statute and
       the scope of the preclusion that would occur
       otherwise, we cannot accept Medtronic’s
       argument that by using the term
       “requirement,” Congress clearly signaled its
       intent to deprive the States of any role in
       protecting consumers from the dangers
       inherent in many medical devices.

Id. at 486–87, 489. Justice Breyer concurred on this point.
He wrote, “[I cannot] find any indication that either Congress
or the FDA intended the relevant FDA regulations to occupy
entirely any relevant field.” Id. at 508 (Breyer, J., concurring
in part and concurring in the judgment).

    Third, the Court held that there was no conflict
preemption. Conflict preemption exists when a state
16              STENGEL V . MEDTRONIC, INC.

requirement actually conflicts with a federal requirement,
making impossible compliance with both requirements, see
Fla. Lime & Avocado Growers, Inc. v. Paul, 373 U.S. 132,
142–43 (1963), or when a state requirement “stands as an
obstacle to the accomplishment and execution of the full
purposes and objectives of Congress,” Hines v. Davidowitz,
312 U.S. 52, 67 (1941). The MDA’s implementing
regulation provides that state requirements are not preempted
if they “are equal to, or substantially identical to,
requirements imposed by or under the act.” 21 C.F.R.
§ 808.1(d)(2). Justice Stevens wrote in Part IV of Lohr that
state requirements that fall within the regulatory definition do
not conflict with the MDA:

            Nothing in § 360k denies Florida the right
        to provide a traditional damages remedy for
        violations of common-law duties when those
        duties parallel federal requirements. . . . The
        presence of a damages remedy does not
        amount to the additional or different
        “requirement” that is necessary under the
        statute; rather, it merely provides another
        reason for manufacturers to comply with
        identical existing “requirements” under
        federal law.

518 U.S. at 495. Justice Breyer again concurred, writing, “I
can find no actual conflict between any federal requirement
and any of the liability-creating premises of the plaintiffs’
state-law tort suit[.]” Id. at 508 (Breyer, J., concurring in part
and concurring in the judgment).

   Our sister circuits have uniformly held that, in cases
dealing with violations of the MDA outside the pre-market
               STENGEL V . MEDTRONIC, INC.                  17

approval process, the MDA does not preempt state-law
causes of action for damages in which the state-law duty
“parallels” the federal-law duty under the MDA. Two cases
are directly on point.

    First, in Hughes v. Boston Scientific Corp., 631 F.3d 762,
765 (5th Cir. 2011), Jan Hughes suffered severe burns when
hot liquid leaked from a Class III medical device
manufactured by Boston Scientific. Hughes brought suit
under Mississippi law, alleging a violation of a state-law duty
to warn. Id. The Fifth Circuit held that Hughes’s state-law
failure-to-warn claim was not preempted “to the extent that
this claim is predicated on Boston Scientific’s failure to
comply with the applicable federal statutes and regulations.”
Id. at 764. The court stated explicitly that its holding
extended to both express and implied preemption: “We
conclude that Hughes’s failure to warn claim is neither
expressly nor impliedly preempted by the MDA to the extent
that this claim is premised on Boston Scientific’s violation of
FDA regulations with respect to reporting burns caused by
the [device].” Id. at 776.

    Second, in Bausch v. Stryker Corp., 630 F.3d 546, 549
(7th Cir. 2010), cert. denied, 132 S. Ct. 498 (2011), Margaret
Bausch was injured by a Class III ceramic hip replacement.
Bausch brought suit against the manufacturer under Illinois
tort law, alleging a violation of state-law duties, premised
upon a violation of parallel federal-law duties under the
MDA. Id. at 549. The Seventh Circuit wrote:

           The central issue in this appeal is whether
       federal law preempts product liability claims
       against manufacturers of Class III medical
       devices where a patient claims that she was
18              STENGEL V . MEDTRONIC, INC.

        harmed by the manufacturer’s violation of
        federal law. That statement of the issue may
        be a little startling. The idea that Congress
        would have granted civil immunity to medical
        device manufacturers for their violations of
        federal law that hurt patients is, to say the
        least, counter-intuitive.

Id. The court concluded that Bausch’s state-law claims were
neither expressly nor impliedly preempted, writing that
“federal law does not preempt parallel claims under state law
based on a medical device manufacturer’s violation of federal
law . . . .” Id. at 558.

     The Eighth Circuit has also addressed preemption under
the MDA. In In re Medtronic, Inc., Sprint Fidelis Leads
Products Liability Litigation, 623 F.3d 1200, 1203 (8th Cir.
2010), plaintiffs in multidistrict litigation alleged that a Class
III cardiac defibrillator wire manufactured by Medtronic was
defective. Plaintiffs alleged various torts under state laws,
including failure to warn. The Eighth Circuit held that the
MDA preempted both of the plaintiffs’ failure-to-warn
claims.     First, plaintiffs sought to enforce state-law
requirements that would have required Medtronic “to give
additional warnings, precisely the type of state requirement
that is ‘different from or in addition to’ the federal
requirement[.]” Id. at 1205 (quoting Riegel, 552 U.S. at 330).
Second, the plaintiffs sought to bring actions based solely on
the MDA rather than on state law, which the court found
foreclosed by Buckman. Id. at 1205–06. At no point did the
court address a state-law claim based on a state-law duty that
paralleled a federal-law duty, and thus Sprint Fidelis is not
inconsistent with Hughes and Bausch.
               STENGEL V . MEDTRONIC, INC.                19

        IV. The Proposed Amended Complaint

    The new claim in the Stengels’ proposed amended
complaint alleges that, under federal law, Medtronic had a
“continuing duty to monitor the product after pre-market
approval and to discover and report to the FDA any
complaints about the product’s performance and any adverse
health consequences of which it became aware and that are or
may be attributable to the product.” It further alleges that
Medtronic failed to perform its duty under federal law to
warn the FDA. Finally, the complaint alleges that, because
Medtronic failed to comply with its duty under federal law,
it breached its “duty to use reasonable care” under Arizona
negligence law.

    The Stengels’ proposed new claim under Arizona law,
insofar as the state-law duty parallels a federal-law duty
under the MDA, is not preempted. Arizona state law has long
been concerned with the protection of consumers from harm
caused by manufacturers’ unreasonable behavior. Plaintiffs’
claim is brought under settled Arizona law that protects the
safety and health of Arizona citizens by imposing a general
duty of reasonable care on product manufacturers. “‘The
whole modern law of negligence, with its many
developments, enforces the duty of fellow-citizens to observe
in varying circumstances an appropriate measure of prudence
to avoid causing harm to one another.’” Crouse v. Wilbur-
Ellis Co., 272 P.2d 352, 365 (Ariz. 1954) (quoting Pollock,
Law of Torts 17 (15th ed. 1951)). Arizona tort law includes
a cause of action for failure to warn. Under Arizona law,
“negligence standards impose a duty to produce products with
appropriate warning instructions.” Wilson v. U.S. Elevator
Corp., 972 P.2d 235, 237 (Ariz. Ct. App. 1998) (internal
quotation marks omitted). “A product may be unreasonably
20             STENGEL V . MEDTRONIC, INC.

dangerous in the absence of adequate warnings.” Dole Food
Co. v. N.C. Foam Indus., Inc., 935 P.2d 876, 880 (Ariz. Ct.
App. 1996). “The manufacturer of a product must warn of
dangers which he knows or should know are inherent in its
use. This duty may be a continuing one applying to dangers
the manufacturer discovers after sale.” Rodriguez v. Besser
Co., 565 P.2d 1315, 1320 (Ariz. Ct. App. 1977) (citations
omitted), abrogated on other grounds as recognized by Piper
v. Bear Med. Sys., 883 P.2d 407, 414 (Ariz. Ct. App. 1993).

     If a more precise parallel were necessary, the Stengels
have alleged it and Arizona law provides it. The Stengels’
new claim specifically alleges, as a violation of Arizona law,
a failure to warn the FDA. Arizona law contemplates a
warning to a third party such as the FDA. Under Arizona
law, a warning to a third party satisfies a manufacturer’s duty
if, given the nature of the warning and the relationship of the
third party, there is “reasonable assurance that the
information will reach those whose safety depends on their
having it.” Anguiano v. E.I. DuPont de Nemours & Co.,
808 F. Supp. 719, 723 (D. Ariz. 1992), aff’d 44 F.3d 806 (9th
Cir. 1995).

    We do not decide whether plaintiffs can prevail on their
state-law failure-to-warn claim. That question is not before
us. But we do hold, under Lohr, Buckman, and Riegel, that
this claim is not preempted, either expressly or impliedly, by
the MDA. It is a state-law claim that is independent of the
FDA’s pre-market approval process that was at issue in
Buckman. The claim rests on a state-law duty that parallels
a federal-law duty under the MDA, as in Lohr. In holding
that the Stengels’ failure-to-warn claim is not preempted, we
join the Fifth and Seventh Circuits, which reached the same
               STENGEL V . MEDTRONIC, INC.                  21

conclusion with respect to comparable state-law claims in
Hughes and Bausch.

    In light of our decision on the merits of the state-law
claim in the Stengels’ proposed amended complaint, it is not
necessary to address their appeal of the district court’s
evidentiary ruling.

    The Stengels have not appealed the dismissal of the state-
law claims in their original complaint. We agree with the
district court that those claims are preempted as they are
currently pled. The Stengels have not specified in those
claims a state-law duty that parallels a federal-law duty under
the MDA. Now that we have clarified preemption law under
the MDA, it is possible that the Stengels could plead non-
preempted versions of these claims. We leave it to the sound
discretion of the district court to determine whether, in light
of this opinion, the Stengels should be permitted to file a
further amended complaint if they wish to do so.

                         Conclusion

    For the foregoing reasons, we conclude that the MDA
does not preempt the Stengels’ state-law failure-to-warn
claim contained in their proposed amended complaint. We
therefore reverse the decision of the district court and remand
for further proceedings consistent with this opinion.

   REVERSED and REMANDED.
22             STENGEL V . MEDTRONIC, INC.

WATFORD, Circuit Judge, joined by KOZINSKI, Chief
Judge, and THOMAS, SILVERMAN, GRABER,
McKEOWN, and GOULD, Circuit Judges, concurring:

    While I join Judge Fletcher’s opinion, I write separately
to provide a few additional thoughts as to why the state law
failure-to-warn claim alleged in the proposed amended
complaint is not preempted.

    Given the Supreme Court’s preemption decisions in this
area, the Stengels faced a dilemma in framing their failure-to-
warn claim. The most direct way to state the claim would be
to allege that under Arizona law Medtronic owed a post-sale
duty to warn doctors when it learned of adverse events in
which the medical device at issue here caused a death or
serious injury. Regulations issued by the Food and Drug
Administration (FDA) permitted Medtronic to issue such
post-sale warnings, even without receiving prior approval
from the FDA, but those regulations did not require such
warnings. See 21 C.F.R. § 814.39(d). As a result, any
attempt to predicate the Stengels’ claim on an alleged state
law duty to warn doctors directly would have been expressly
preempted under 21 U.S.C. § 360k, which forbids state-
imposed requirements that are “different from, or in addition
to” the requirements imposed by federal law. See McMullen
v. Medtronic, Inc., 421 F.3d 482, 489 (7th Cir. 2005) (“Where
a federal requirement permits a course of conduct and the
state makes it obligatory, the state’s requirement is in
addition to the federal requirement and thus is preempted.”).

    But the Stengels have not predicated their failure-to-warn
claim on a duty to warn doctors directly. They have instead
alleged that Medtronic breached its duty of reasonable care
under Arizona negligence law by failing to report adverse
                STENGEL V . MEDTRONIC, INC.                  23

events to the FDA. That requirement is not “different from,
or in addition to” the requirements imposed by federal law,
because FDA regulations required Medtronic to file an
adverse event report with the FDA if it learned of information
“reasonably suggest[ing]” that one of its devices “[m]ay have
caused or contributed to a death or serious injury,” as the
Stengels have alleged here. 21 C.F.R. § 803.50(a). Framed
in this fashion, the Stengels’ negligence claim is not
expressly preempted because it seeks to hold Medtronic
accountable only for failing to do what federal law mandated
— nothing more. The state law duty, as alleged by the
Stengels, is precisely parallel to the duties imposed by federal
law. See Medtronic, Inc. v. Lohr, 518 U.S. 470, 495 (1996).

    Because they predicate their claim on Medtronic’s
reporting duty to the FDA, as they must to avoid express
preemption, the Stengels face a causation hurdle that would
not otherwise exist. To prevail, they will ultimately have to
prove that if Medtronic had properly reported the adverse
events to the FDA as required under federal law, that
information would have reached Mr. Stengel’s doctors in
time to prevent his injuries. See Hughes v. Boston Scientific
Corp., 631 F.3d 762, 770 n.5, 776 (5th Cir. 2011). But at this
juncture — a request for leave to amend their complaint —
the Stengels’ allegations of causation are adequate.

    Medtronic argues that the Stengels’ choice to predicate
their claim on a reporting duty to the FDA renders the claim
impliedly preempted under Buckman Co. v. Plaintiffs’ Legal
Committee, 531 U.S. 341 (2001). In that case, the plaintiffs
asserted a state law fraud claim based on purported
misrepresentations made to the FDA during the premarket
approval process for the medical device at issue. Id. at 343.
The Supreme Court held that this claim was impliedly
24              STENGEL V . MEDTRONIC, INC.

preempted because it sought to enforce an exclusively federal
requirement and was not grounded in traditional state tort
law. Id. at 352–53. Likewise here, Medtronic argues, the
Stengels’ failure-to-warn claim seeks to enforce an
exclusively federal requirement and is not based on
traditional state tort law because Arizona law has never
required adverse events to be reported to the FDA.

    In my view, accepting that argument would require an
unwarranted expansion of Buckman’s rationale. Central to
the Court’s reasoning in Buckman was that the state law claim
asserted there “exist[ed] solely by virtue” of the federal
enactments, id. at 353 (emphasis added), because state law
traditionally had no role to play in policing “the relationship
between a federal agency and the entity it regulates,” id. at
347. But Buckman left intact claims “relying on traditional
state tort law which had predated the federal enactments” in
question. Id. at 353.

     In this case, Medtronic’s failure to report was more than
a mere misrepresentation to the FDA because it
simultaneously misled the device’s current and potential
users, to whom Medtronic owed an independent duty under
state law. There is no question that state law has an important
and legitimate role to play in regulating the adequacy of post-
sale warnings for products already on the market. That
Arizona law did not previously address reporting duties to the
FDA specifically is irrelevant; nothing in Buckman suggests
that the preexisting state law needs to mirror the federal
requirement at that level of specificity to avoid preemption.
It is sufficient here that, in contrast to Buckman, the Stengels’
claim is grounded in a traditional category of state law
failure-to-warn claims that predated the federal enactments in
               STENGEL V . MEDTRONIC, INC.                  25

question, and that the claim therefore does not exist solely by
virtue of those enactments.
