                        UNPUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


N&N CONTRACTORS, INCORPORATED,       
                      Petitioner,
                v.
OCCUPATIONAL SAFETY & HEALTH                  No. 00-1734
REVIEW COMMISSION; ALEXIS M.
HERMAN, SECRETARY OF LABOR,
                     Respondents.
                                     
               On Petition for Review of an Order
    of the Occupational Safety & Health Review Commission.
                             (96-606)

                     Argued: March 1, 2001

                      Decided: May 9, 2001

    Before WILKINS, MOTZ, and TRAXLER, Circuit Judges.



Petition denied by unpublished per curiam opinion.


                           COUNSEL

ARGUED: Randi Klein Hyatt, KOLLMAN & SHEEHAN, P.A.,
Baltimore, Maryland, for Petitioner. John Robert Shortall, UNITED
STATES DEPARTMENT OF LABOR, Washington, D.C., for
Respondents. ON BRIEF: Frank L. Kollman, KOLLMAN & SHEE-
HAN, P.A., Baltimore, Maryland, for Petitioner. Henry L. Solano,
Solicitor of Labor, Joseph M. Woodward, Associate Solicitor for
Occupational Safety and Health, Bruce F. Justh, Counsel for Appel-
2                N&N CONTRACTORS, INC. v. OSHRC
late Litigation, UNITED STATES DEPARTMENT OF LABOR,
Washington, D.C., for Respondents.



Unpublished opinions are not binding precedent in this circuit. See
Local Rule 36(c).


                             OPINION

PER CURIAM:

  N&N Contractors, Inc. ("N&N") petitions for review of an order
of the Occupational Safety and Health Review Commission ("the
Commission") holding that N&N violated 29 C.F.R. § 1926.501(b)(1)
(1999), and assessing a penalty. We deny the petition.

                                  I.

   N&N is an erector of precast concrete panels. Krzysztos Radzicki
was an employee of N&N working on the construction of a twelve-
story building in the District of Columbia. On March 18, 1996, Radz-
icki was working on the edge of the eleventh floor in an area without
guardrails or safety nets, but with a perimeter cable approximately six
and a half feet from the edge that could be used as a tie-off point for
safety harnesses.1 While preparing to reset a precast column, Radzicki
ducked under the cable without tying off, lost his footing, and
plunged to his death.

   Following an investigation, the Secretary of Labor ("the Secre-
tary") charged N&N with a willful violation of 29 C.F.R.
§ 1926.501(b)(1), which requires that employees working on a sur-
face "with an unprotected side or edge which is 6 feet (1.8m) or more
above a lower level shall be protected from falling by the use of guar-
    1
    A person normally "ties off" by securing a rope lanyard, which is
attached to the safety harness worn by the worker, to a cable or some
structure capable of supporting the person’s weight.
                  N&N CONTRACTORS, INC. v. OSHRC                       3
drail systems, safety net systems, or personal fall arrest systems." The
violation carried a proposed penalty of $49,000. The Secretary also
cited N&N for willful failure to "provide a training program for each
employee who might be exposed to fall hazards," 29 C.F.R.
§ 1926.503(a)(1) (1999), and for failure to prepare written certifica-
tion of the training program, see 29 C.F.R. § 1926.503(b)(1) (1999).

   N&N contested the citations and a hearing was held before an
administrative law judge. See 29 U.S.C.A. §§ 659(c), 661(j) (West
1999). N&N withdrew its challenge to the charge of failing to prepare
written certification of its training program, and the administrative
law judge affirmed the other two violations. However, the judge
recategorized the two violations from "willful" to "serious," and
reduced N&N’s penalty to $9,800 ($4,900 for each violation). Unsat-
isfied with the judge’s decision, N&N petitioned the Commission for
review. See 29 U.S.C.A. § 661(j). The Commission vacated the cita-
tion dealing with the inadequacy of N&N’s training program, but
affirmed the failure to take proper precautions to prevent falls and the
corresponding $4,900 penalty. N&N now petitions this court for
review of the Commission’s decision.

                                   II.

   The Commission’s findings of fact, "if supported by substantial
evidence on the record considered as a whole, shall be conclusive."
29 U.S.C.A. § 660(a) (West 1999); George Hyman Constr. Co. v.
OSHRC, 582 F.2d 834, 837 n.4 (4th Cir. 1978). "Substantial evidence
is such relevant evidence as a reasonable mind might accept as ade-
quate to support a conclusion." NLRB v. Peninsula Gen. Hosp. Med.
Ctr., 36 F.3d 1262, 1269 (4th Cir. 1994) (internal quotation marks
omitted). Though substantial evidence must certainly amount to more
than a scintilla, it may also be less than a preponderance. See AT&T
Wireless PCS, Inc. v. City Council, 155 F.3d 423, 430 (4th Cir. 1998)
As for the interpretation of regulations, this court must accord defer-
ence to the Secretary’s interpretation so long as it is not unreasonable.
See Martin v. OSHRC, 499 U.S. 144, 158 (1991).2
  2
    Under the Occupational Safety and Health Act of 1970, 29 U.S.C.A.
§§ 651-78 (West 1999 & Supp. 2000), the Secretary is charged with
crafting and enforcing safety standards in the workplace, and the Com-
mission is charged with adjudicating matters concerning those standards.
See Martin, 499 U.S. at 147.
4                 N&N CONTRACTORS, INC. v. OSHRC
   To establish a violation of an occupational safety or health stan-
dard, the Secretary must prove by a preponderance of the evidence (1)
the applicability of the standard, (2) the employer’s noncompliance
with the terms of the standard, (3) employee access to the violative
condition, and (4) the employer’s actual or constructive knowledge of
the violation. See Secretary of Labor v. Brand Scaffold Builders, Inc.,
OSHRC Docket No. 00-1331, 2001 WL 118562, at *2 (Feb. 5, 2001).

   First, N&N argues that the Commission erred in determining that
N&N failed to comply with the standard. According to N&N,
§ 1926.501(b)(1) does not give adequate notice of its requirements
because it fails to specify at what distance from an unprotected edge
that fall protection must be used or indicate whether an employee is
required to tie off before crossing perimeter cables. Section
1926.501(b) commands that an employee on an unprotected surface
that is six feet or more above a lower level must be protected by the
use of guardrails, safety nets, or safety harnesses. The plain language
of the regulation identifies both the hazard to be guarded against and
the specific safety precautions to be taken. Cf. Modern Continen-
tal/Obayashi v. OSHRC, 196 F.3d 274, 281 (1st Cir. 1999) (rejecting
a vagueness challenge to a similarly worded regulation, 29 C.F.R.
§ 1926.501(b)(7)(ii), and concluding that "[t]he plain language identi-
fies a specific hazard and delineates a specific precaution"). In this
regard, the regulation is in no sense vague.

   To the extent that the regulation is ambiguous because it does not
specifically state the distance from the edge an employee should tie
off or that the employee should tie off before crossing a perimeter
cable, we must defer to the Secretary’s interpretation if reasonable.
See Martin, 499 U.S. at 158. The Secretary, along with the adminis-
trative law judge and the Commission, interprets the regulation as
requiring the prescribed safety precautions be fully implemented
before the employee is exposed to the hazard. In other words, an
employee wearing a personal fall arrest system must be tied off the
moment he is exposed to the hazard of falling. As the Secretary points
out, a fall arrest system is useless unless it is properly secured as soon
as the danger of falling arises. The Secretary’s reading of the regula-
tion is reasonable and consistent with the purpose of the Occupational
Safety and Health Act of 1970: "[T]o assure so far as possible . . . safe
and healthful working conditions" for "every working man and
                  N&N CONTRACTORS, INC. v. OSHRC                        5
woman in the Nation." 29 U.S.C.A. § 651(b) (West 1999); see also
Bethlehem Steel Corp. v. Donovan, 727 F.2d 1358, 1362 (4th Cir.
1984) (considering "[t]he preventative intent of the regulation" and
purposes of the Act when giving deference to the Secretary’s interpre-
tation). In the present case, Radzicki was six and a half feet away
from an unprotected edge, yet ducked under the perimeter cable with-
out tying off. Being so close to the edge, Radzicki encountered the
obvious risk of falling without making use of his personal fall arrest
system. See Corbesco, Inc. v. Dole, 926 F.2d 422, 427 (5th Cir. 1991)
(taking into account "the obviousness of the hazard" when deciding
whether a fall prevention regulation provided sufficient notice). This
conduct is contrary to both the language of the regulation as well as
the Secretary’s reasonable interpretation. Cf. Mullane v. Central Han-
over Bank & Trust Co., 339 U.S. 306, 314 (1950) (observing that rea-
sonableness is the key to sufficient notice). Accordingly, the
Commission did not err in concluding that N&N failed to comply
with the applicable standard.

   Second, N&N contends that the Commission should be reversed
because Radzicki was not in the zone of danger. To establish
employee exposure to a risk of injury, the Secretary must demonstrate
"that it is reasonably predictable either by operational necessity or
otherwise (including inadvertence), that employees have been, are, or
will be in the zone of danger." Secretary of Labor v. Pete Miller, Inc.,
OSHRC Docket No. 99-947, 2000 WL 1810060, at *2 (Dec. 8, 2000).
Given the nature of the work involved, erection of precast concrete
panels on the unprotected edges of a multistory building, "by opera-
tional necessity" Radzicki was required to labor in an area where
there was a risk of falling. See id. (finding that it was reasonably fore-
seeable an employee would enter the zone of danger due to "the
nature of his work"). Radzicki’s presence in the zone of danger was
reasonably predictable, and therefore the Commission did not err in
concluding that Radzicki was in the zone of danger.

   Finally, N&N contends that it did not have constructive knowledge
of the violation. An employer has constructive knowledge of a viola-
tion if the employer fails to use reasonable diligence to discern the
presence of the violative condition. See Secretary of Labor v. Pride
Oil Well Serv., OSHRC Docket No. 87-692, 1992 WL 215112, at *6
(Aug. 17, 1992). Factors relevant in the reasonable diligence inquiry
6                N&N CONTRACTORS, INC. v. OSHRC
include the duty to inspect the work area and anticipate hazards, the
duty to adequately supervise employees, and the duty to implement
a proper training program and work rules. See id. at *6-7. The Com-
mission agreed with the administrative law judge that constructive
knowledge in this case was derived from evidence that N&N "em-
ployees had a tendency to ignore the use of fall protection while
working on unprotected sides and edges." J.A. 616 (internal quotation
marks omitted). Substantial evidence in the record supports this find-
ing. In November 1995, the general contractor issued two safety vio-
lations to N&N. The first violation was for a laborer "working outside
of perimeter protection without fall protection." J.A. 50. The second
violation concerned three N&N employees working near the edge of
the building without fall protection equipment, and a later incident
where the men tied off to a portable machine that could not have sup-
ported their weight had there been a fall. See J.A. 50, 120-21. Finally,
an N&N supervisor acknowledged discovering in early 1996 that
N&N employees frequently came within two or three feet of the edge
of the building without tying off. See J.A. 563. This disregard of fall
prevention measures by N&N employees clearly supports the Com-
mission’s finding that N&N had constructive knowledge that Radz-
icki would enter the zone of danger without tying off.

   Appealing to the law of this circuit, N&N claims that the Commis-
sion impermissibly shifted the burden of proof on the knowledge
inquiry. In Ocean Electric Corp. v. Secretary of Labor, 594 F.2d 396
(4th Cir. 1979), we made clear that the burden concerning the ade-
quacy of safety measures rests on the Secretary. Id. at 403; see also
L.R. Willson & Sons, Inc. v. OSHRC, 134 F.3d 1235, 1240-41 (4th
Cir. 1998). Contrary to N&N’s assertion, the Commission acknowl-
edged our decision in Ocean Electric, see J.A. 620, and found that the
Secretary had met her burden in establishing constructive knowledge.
Moreover, the Commission opinion indicates that the constructive
knowledge inquiry did not turn on burden of proof rules, and there-
fore even if the Commission had impermissibly shifted the burden the
error would be harmless. See Applewood Landscape & Nursery Co.
v. Hollingsworth, 884 F.2d 1502, 1506 (1st Cir. 1989) (holding that
even if the district court improperly allocated the burden of proof on
a particular issue, the error was harmless because the district court’s
                  N&N CONTRACTORS, INC. v. OSHRC                        7
decision on that issue turned on the weight of the evidence in the
record and not on burden of proof rules).3

                                   III.

   For the foregoing reasons, we uphold the decision of the Commis-
sion. Accordingly, the petition is denied.

                                                   PETITION DENIED
  3
    N&N also argues that because Radzicki’s failure to take adequate
safety precautions amounted to an isolated incident, it is entitled to the
affirmative defense of unpreventable employee misconduct. See Secre-
tary of Labor v. Murray Roofing Co., OSHRC Docket No. 98-0923, 1999
WL 717820, at *5 (Sept. 3, 1999). As demonstrated in our discussion of
N&N’s constructive knowledge of the violation, the failure to tie off
when in the zone of danger was not unique to Radzicki. Numerous N&N
employees were guilty of the same violation. As with the constructive
knowledge issue, N&N contends that the burden of proof was imper-
missibly placed on it. The Commission did not place the burden of proof
on N&N, and even if the Commission had made such an error, the Com-
mission’s opinion indicates that the employee misconduct issue did not
turn on burden of proof rules. See Hollingsworth, 884 F.2d at 1506.
Accordingly, the Commission did not err in denying N&N the affirma-
tive defense of unpreventable employee misconduct.
