                           PUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


WILLIAM T. KNOX,                         
                           Petitioner,
                 v.                              No. 04-2486
UNITED STATES DEP’T OF LABOR,
                       Respondent.
                                         
                On Petition for Review of an Order
            of the United States Department of Labor.
                        (03-40; 01-CAA-3)

                      Argued: October 25, 2005

                      Decided: January 17, 2006

     Before MOTZ, TRAXLER, and SHEDD, Circuit Judges.



Petition granted and remanded by published opinion. Judge Shedd
wrote the opinion, in which Judge Motz and Judge Traxler joined.


                             COUNSEL

ARGUED: Richard Edward Condit, PUBLIC EMPLOYEES FOR
ENVIRONMENTAL RESPONSIBILITY, Washington, D.C., for
Petitioner. Mary J. Rieser, UNITED STATES DEPARTMENT OF
LABOR, Office of the Solicitor, Washington, D.C., for Respondent.
ON BRIEF: Howard M. Radzely, Solicitor of Labor, Steven J.
Mandel, Associate Solicitor, Paul L. Frieden, Counsel for Appellate
Litigation, UNITED STATES DEPARTMENT OF LABOR, Wash-
ington, D.C., for Respondent.
2                    KNOX v. U.S. DEP’T OF LABOR
                              OPINION

SHEDD, Circuit Judge:

   William T. Knox filed an administrative complaint claiming that
his employer, the United States Department of Interior ("DOI"), vio-
lated the whistle-blower provision of the Clean Air Act ("CAA"), 42
U.S.C. § 7622 (2005). An Administrative Law Judge ("ALJ") granted
Knox relief on his complaint. The DOI appealed the ALJ’s decision
to the Administrative Review Board ("ARB") of the United States
Department of Labor ("DOL"), which dismissed the complaint based
on its conclusion that Knox did not engage in a protected activity
under the CAA. Knox seeks judicial review of the ARB’s decision.
We grant Knox’s petition for review and remand for further proceed-
ings consistent with this opinion.

                                   I.

   Knox began working as a Training Instructor at the National Park
Service Job Corps Center ("Center") in Harper’s Ferry, West Virginia,
on November 21, 1999.1 Knox’s duties included acting as the safety
officer for the Center. While accompanying a United States DOL
Occupational Safety and Health Administration ("OSHA") officer on
a regularly scheduled safety inspection of the Center’s facilities in
December 1999, Knox learned that some of the Center’s buildings
contained asbestos. At some point, Knox also found an "Asbestos
Survey Report" dated September 8, 1993, and an OSHA "Notice of
Unsafe or Unhealthful Conditions" issued after a previous inspection
in January 1999. Both noted the presence of asbestos in buildings at
the Center.

  In January 2000, Knox told DOI management officials that the
Center had an asbestos problem. He said that employees, students,
and contractors at the Center may have been exposed to hazardous
asbestos in the workplace and that they should be informed of their
potential exposure. Knox testified that, after raising his asbestos con-
cerns, DOI management threatened to reduce his job duties and pay.
    1
   This recitation of the facts underlying Knox’s claim is taken from the
findings of the ARB in its order of dismissal. J.A. 100-01.
                     KNOX v. U.S. DEP’T OF LABOR                       3
   After receiving this threat, Knox filed the first of three whistle-
blower actions with the Merit Systems Board, in which he contended
that he was exposed to asbestos and that he worked in unsafe and
unhealthful conditions. Knox then wrote a letter to the DOI Office of
Special Counsel in February 2000, again expressing his concern that
employees, students, and contractors had been exposed to asbestos at
the Center. Knox also faxed a letter to DOI Secretary Bruce Babbitt
on March 7, 2000, stating that DOI managers had harassed and dis-
criminated against him because he had revealed the asbestos problems
at the Center.

   On March 13, 2000, the director of the Center, Jay Weisz, fired Knox.2
Weisz believed Knox was a probationary employee whose employ-
ment could be terminated at will. Upon discovering that Knox was
actually a permanent employee, the DOI reinstated Knox on March
18, 2000, and removed all reference to the firing from his record.

   Knox filed this whistle-blower action in April 2000 alleging viola-
tions of the CAA. An ALJ conducted a hearing and issued a recom-
mended decision and order concluding that the DOI had violated the
CAA. The ALJ stated that "[t]he totality of this closed record ineluc-
tably lends to the conclusion that Mr. Knox had engaged in protected
activities, that the [DOI], through its agents and employees, knew of
such activities and that Mr. Knox experienced adverse personnel
actions solely because of such activities." J.A. 15. The ALJ ordered
reinstatement, back pay, compensatory damages, exemplary damages,
and attorneys’ fees. The ALJ also prohibited the DOI from further
retaliation, ordered it to clear Knox’s record, and required it to pub-
licly post the order.

   Upon the DOI’s appeal, the ARB rejected the ALJ’s analysis and
dismissed Knox’s complaint. The ARB reasoned that because the
CAA is concerned with the pollution of "ambient air," i.e., air external
to buildings, and Knox only complained of asbestos within his work-
place, he did not engage in protected activity under the CAA. Specifi-
cally, under the ARB’s announced standard, "[t]o establish that he
engaged in CAA protected activity, Knox must prove that when he
expressed his concerns about the asbestos to DOI managers, the DOI
  2
   The ARB’s order does not provide the reasons for Knox’s firing.
4                    KNOX v. U.S. DEP’T OF LABOR
office of Special Counsel, and Secretary Babbitt, he reasonably
believed that DOI was emitting asbestos into the ambient air." J.A.
102. Determining that Knox made no such showing, the ARB dis-
missed his complaint. Knox filed this petition for review of the
ARB’s order.

                                  II.

   Under the Administrative Procedure Act ("APA"), federal courts
can overturn an administrative agency’s decision only if it is "arbi-
trary, capricious, an abuse of discretion, or otherwise not in accor-
dance with the law," or "unsupported by substantial evidence." 5
U.S.C. § 706(2)(A), (E) (2005). Pursuant to the APA’s scheme of rea-
soned decisionmaking, an administrative agency "must be required to
apply in fact the clearly understood legal standards that it enunciates
in principle." Allentown Mack Sales & Serv., Inc. v. NLRB, 522 U.S.
359, 376 (1998). We review the ARB’s interpretation of the CAA
under the deferential standard set forth in Chevron U.S.A., Inc. v. Nat-
ural Resources Defense Council, Inc., 467 U.S. 837 (1984).

                                  III.

   The CAA is a comprehensive program for controlling and improv-
ing the nation’s air quality. 1000 Friends of Md. v. Browner, 265 F.3d
216, 220 (4th Cir. 2001). The whistle-blower provision of the CAA
prohibits an employer from discharging or discriminating against an
employee for instituting proceedings for enforcement of the Act or
carrying out the purposes of the Act. 42 U.S.C. § 7622(a); see also 29
C.F.R. § 24.2 (2005). To state a claim under the whistle-blower provi-
sion, an employee must establish that his employer retaliated against
him because he engaged in a protected activity. See Sasse v. United
States DOL, 409 F.3d 773, 779 (6th Cir. 2005).

   The ARB concluded that Knox’s whistle-blower claim fails
because he did not engage in a protected activity. As noted above, the
ARB held that "[t]o establish that he engaged in CAA protected activ-
ity, Knox must prove that when he expressed his concerns about the
asbestos to DOI managers, the DOI office of Special Counsel, and
Secretary Babbitt, he reasonably believed that DOI was emitting
asbestos into the ambient air." J.A. 102. In his petition for review,
                     KNOX v. U.S. DEP’T OF LABOR                       5
Knox argues that the ARB read the CAA too narrowly when it set
forth this standard for protected activity. Even assuming, as the DOL
argues, that the ARB’s standard is a permissible construction of the
CAA under Chevron, we nonetheless find that its application of this
standard was improper under the circumstances of this case.3

   In considering whether Knox proved that he reasonably believed
that asbestos was emitting into the ambient air, the ARB cited evi-
dence showing that Knox’s complaints to management concerned the
presence of asbestos in the workplace generally, as opposed to the
potential that asbestos was emitting into the ambient air. However, the
ARB then stated:

      On the other hand, we are quick to point out that Knox testi-
      fied that he observed asbestos escaping into the outside,
      ambient air via an exhaust fan in the maintenance shop of
      the Job Corps Center. But Knox’s burden is to prove that
      when he actually expressed concerns about asbestos to DOI
      management officials, he reasonably believed that asbestos
      was escaping into the air outside the Center’s buildings,
      thereby posing a risk to the general public. We have no evi-
      dence that Knox ever told DOI officials about the exhaust
      fan. Consequently, testimony merely that he observed asbes-
      tos escaping through the exhaust fan does not establish that
      Knox’s activities are protected under the CAA.
  3
    We are not convinced that a reasonable belief of a release into the
ambient air is even the correct standard in all cases under the whistle-
blower provision of the CAA. There are several ways to violate the CAA
and its implementing regulations without releases into the ambient air.
See, e.g., 42 U.S.C. § 7412(h)(1) (allowing EPA to establish work prac-
tice standards for pollutants such as asbestos); 40 C.F.R. § 61.150 (set-
ting forth standards for "waste disposal for manufacturing, fabricating,
demolition, renovation, and spraying operations" involving asbestos,
some of which can be violated without releases of asbestos into the ambi-
ent air); United States v. Ho, 311 F.3d 589, 594-95 (5th Cir. 2002) (dis-
cussing work practice standards involving asbestos). Thus, depending on
the circumstances, an employee could reasonably believe his employer
was violating the CAA, even if no release into the ambient air occurred.
6                    KNOX v. U.S. DEP’T OF LABOR
J.A. 104.

   From the quoted paragraph, it is apparent that the ARB altered its
protected activity standard from an inquiry into Knox’s reasonable
beliefs to a requirement that Knox actually conveyed his reasonable
beliefs to management. Although the contents of Knox’s complaints
may provide evidence of his reasonable beliefs, it does not follow that
he must have necessarily conveyed a notion to have reasonably
believed it, as the ARB demanded of him. Indeed, in the very first
sentence of this paragraph, the ARB seemed to accept as true, evi-
dence that Knox did, in fact, reasonably believe that asbestos was
emitted into the ambient air.4 Given the standard that the ARB ini-
tially announced, requiring Knox to have reasonably believed that
asbestos was being emitted into the ambient air, and the ARB’s
acceptance that Knox observed asbestos escaping into the ambient air,
we conclude that Knox has engaged in a protected activity under the
CAA as interpreted by the ARB.

                                   IV.

   Accordingly, we grant the petition for review and remand the case
for further proceedings consistent with this opinion.5

                            PETITION GRANTED AND REMANDED
    4
     Because the ARB required Knox to convey his reasonable beliefs to
management to have engaged in a protected activity, it applied a different
standard than formally announced and breached the requirement of rea-
soned decisionmaking under the APA. See Allentown, 522 U.S. at 374
("It is hard to imagine a more violent breach of that requirement [of rea-
soned decisionmaking] than applying a rule of primary conduct or a stan-
dard of proof which is in fact different from the rule or standard formally
announced.").
   5
     The ARB must now determine whether the DOI retaliated against
Knox because he engaged in that protected activity. See Sasse, 409 F.3d
at 779. While the protected activity standard announced by the ARB did
not require Knox to convey his reasonable beliefs to DOI management,
DOI’s awareness of his complaints may prove relevant in an analysis of
the causal connection between his protected activity and the adverse
action.
