Cоrbesco, Inc., has petitioned this court to review a decision by an administrative law judge (AU) of the Occupational Safety and Health Review Commission (the “Commission”), who found that Corbesco committed a serious violation of the Occupational Safety and Health Act of 1970 (the “OSH Act”) by failing to install a safety net at one of its construction sites. The citation was issued after one of Corbesco’s employees was killed when he was blown off of the flat roof of an aircraft hangar. Corbesco contends that its right to due process was violated because the regulation under which it was cited, 29 C.F.R. § 1926.105(a), is a general one and fails to give an employer adequate notice that it must use a safety net when its employees are working on the flat roof of a large building, like an aircraft hanger.
Although we agree that section 1926.-105(a) is a general industry standard, the Commission has consistently held that this regulation requires an employer to install a safety net even if the roof on which its employees are working is flat. These numerous holdings sufficiently notified Cor-besco of its duty under the regulation; therefore, its right to due process was not violated, and we AFFIRM.
I.
FACTS AND PROCEDURAL HISTORY
Corbеsco is an industrial roofing and siding installation company that was hired to put metal roofing and siding over the skeletal structure of five aircraft hangers at the Chennault Air Base in Lake Charles, Louisiana. In April 1987, Corbesco assigned three of its employees, two journeymen ironworkers and an apprentice, to work on the partially completed roof of Hangar B, a large single-story building, sixty feet high, 374 feet wide, and 574 feet long. The ironworkers were working off of the completed portion of one vertical half of the roof, the slope of which, from the peak to the eave, was very slight: one vertical inch for every horizontal foot. 1 The AU found that slope of the roof created no danger of slippage, and, therefore, “for all practical purposes, it was a flat roof.” See Corbesco, Inc., OSHRC Docket No. 87-0611, at 3 n. 3, reprinted in Record on Appeal, vol. 1 (referred to hereafter as the “Commission Opinion”). 2
Before the ironworkers could lay the aluminum sheet metal roofing, they had to install insulation. To do this, they first would push a long sheet of corrugated metal away from the edge of the completed portion of the roof, leaving an exposed network of purlins and beams about six feet wide and 102 feet long. Next, they would roll out a six foot wide sheet of insulation onto the completed roof. Then, either kneeling or standing on the edge of the roof, they would shake the insulation out onto the exposed grid of rafters, just as one might shake out a bedspread over a *425 bed. Because the workers had to maintain their balance while leaning over the edge of the roof, high winds could be very dangerous. Therefore, Corbesco regularly sought wind and weather forecasts from the National Weather Service.
On April 2, 1987, one of the ironworkers, Roger Mathew, was on his knees shaking out insulation when a gust of wind caught the sheet of insulation he was holding and pulled him forward. Mathew lost his balance and fell sixty feet through the open structure of steel to the concrete below. Mathew was killed by the fall. The record does not reveal whether Corbesco telephoned the Weather Service that day.
The next day, a compliance officer from the Occupational Safety and Health Administration (OSHA) inspected the hangar where Mathew had fallen and assessed a $1000 penalty against Corbesco for failing to a install safety net under the roof. The regulation cited by the officer was 29 C.F.R. § 1926.105(a), which provides that “[sjafety nets shall be provided when workplaces are more than 25 feet above the ground or water surface, or other surfaces where the use of ladders, scaffolds, catch platforms, temporary floors, safety lines, or safety belts is impractical.”
See
OSH Act, § 5(a)(2), 29 U.S.C.A. § 654(a)(2) (West 1985) (requiring employers to comply with promulgated occupational safety and health standards). The parties agree that none of the safety devices other than nets would have been practical. Because the officer determined that the absence of a safety net at the hangar presented “a substantial probability that death or serious physical harm could result,” he classified the violation as “serious.”
See
OSH Act, § 17(k), 29 U.S.C.A. § 666(k).
See also Phoenix Roofing, Inc. v. Dole,
After the citation was given, Corbesco installed a safety net in the unfinished hanger, but it filed a notice of contest with the Department of Labor, and a hearing was conducted before an administrative law judge. At the hearing, Corbesco demonstrated that the custom and prаctice of the industry were that ironworkers did not use safety nets while working on flat roofs. See Commission Opinion at 3 n. 4. It also pointed out that OSHA officers had made several inspections of the hangar construction project while roofing work was being done and that the inspectors did not instruct Corbesco to use safety nets. As a consequence, Corbesco argued that it had no way of knowing that it was violating section 1926.105(a). The AU disagreed and affirmed the citation. He did, however, acknowledge that Corbesco had a good safety program and that its violation was not in bad faith. Therefore, he reduced the penalty to $50. See Commission Opinion at 14 — 15, 15 n. 31.
Corbesco petitioned the Commission for discretionary review. When no Commissioner directed that the case be reviewed, the decision оf the AU became a final order of the Commission. See OSH Act, § 12(j), 29 U.S.C.A. § 661(j) (West 1985). Corbesco now asks us to review that order. See id. § 11(a), 29 U.S.C.A. § 660(a).
II.
A. STANDARD OF REVIEW
We are bound by the AU’s factual findings if they are supported by the record.
Cleveland Consol., Inc. v. Occupational Safety and Health Review Comm’n,
B. CORBESCO'S DUE PROCESS ARGUMENT
Corbesco argues that section 1926.105(a) is a “general” regulation and that because
*426
the custom in this industry was not to use safety equipment, the Secretary of Labor (Secretary) was required to show that Cor-besco had actual knowledge that it was required to furnish a safety net in order to comply with the regulation.
See S & H Riggers & Erectors, Inc. v. Occupational Safety & Health Review Comm’n,
This court reversed the Commission’s decision in all three cases. To comply with the due process requirement of the fifth amendment to the Constitution when issuing a citation under section 1926.28(a),
the Secretary bears the burden of proving either that the employer failed to provide personаl protective equipment to its employees under circumstances in which it is the general practice in the industry to do so or that the employer had clear actual knowledge that personal protective equipment was necessary under the circumstances.
Id. at 1285. Corbesco argues that the Secretary has the same duty under section 1926.105(a) and that, thereforе, the Commission’s decision must be reversed. The Secretary concedes that the general industry practice is that safety nets are not used when workers install roofing on large flat-roofed buildings such as aircraft hangars. The Secretary also concedes that Corbesco did not have “actual” knowledge that section 1926.105(a) required it to install a safety net; this is why Corbesco was not cited for “willfully” violating the regulation. See Record on Appeal, vol. 2, at 64 (testimony of OSHA Safety Specialist, Thomas Staggs). The Secretary’s position, however, is that section 1926.105(a) is a “specific” standard, rather than a general one and, therefore, that the constitutional duty established by S & H Riggers does not apply to this case.
Section 1926.105(a) is “general” in that it applies to the entire construction industry rather than to one pаrticular segment of it.
See Century Steel Erectors, Inc. v. Dole,
The touchstone for sufficiency of notice under the due process clause is reasonableness.
See Mullane v. Central Hanover Bank & Trust Co.,
Put another way, the Secretary has the burden to prove that Corbesco had actual or constructive notice that section 1926.105(a) required it to install a safety net. To determine whether the Secretary has met that burden, we must examine the language of the regulation in the light of Corbesco’s conduct.
See United States v. National Dairy Prods. Corp.,
If a workplace is more than twenty-five feet above the ground, an employer must furnish some form of fall protection.
See Cleveland Consol.,
In Brennan, a construction company was cited for violating section 1926.-105(a) after an inspection officer discovered a welder working off a scaffold and a hoist operator working off of a roof, neither of whom were using a safety net or other safety device. See id. at 338. The company argued that the citation was inappropriate because the roof was a “temporary floor,” and section 1926.105(a) requires an employer to use nets only if the use of scaffolds or temporary floors is “impractical.” The Secretary asserted, however, that a safety device could not substitute for a net unless that device provided fall protection. See id. This court did not *428 reject the Secretary’s interpretation of section 1926.105(a), but it held that the word “impractical” was too imprecise to convey that interpretation to the emplоyer. Therefore, the court vacated the citation. See id. at 338-39.
We have our doubts about whether the language of section 1926.105(a) is specific enough to provide constructive notice that a safety net is required when ironworkers are working on a flat-roofed building larger than a football field.
See Forest Park Roofing Co.,
Moreover, we do not believe that the Commission has abused its discretion by determining that a flat roof cannot be a temporary floor. The purpose of the safety devices listed in the regulation is to provide fall protection, and a roof cannot provide fall protection if workers must operate along the perimeter.
See Williams Enters.,
We emphasize that the sole issue before this court is whether the Secretary violated Corbesco’s constitutional right to due process by citing it for violating section 1926.105(a). Although there was some evidence in the record to indicate that it was not economically feasible for Corbesco to install safety nets in the aircraft han *429 gers, 5 Corbesco did not argue that affirmative defense to this court and, therefore, has waived it. See Fed.R.App.P. 28(a); C. Wright, A. Miller, E. Cooper & E. Gressman, Federal Practice and Procedure § 3974, at 421 n. 1 (1977 & Supp.1990) (citing cases). Moreover, a сonstruction company that believes the cost of complying with an OSHA standard will outweigh the benefits of enhanced safety need not wait until it is cited to argue that compliance is infeasible. The company can seek a variance from the standard. See 29 C.F.R. § 1926.2 (1990); 29 C.F.R. §§ 1905.1 to 1905.51 (1990). Corbesco never pursued this alternative.
III.
The Secretary did not violate Corbesco’s right to due process because Corbesco had constructive notice that it was required to install safety nets under its crew while they were working on the edge of a flat roof some sixty feet above a concrete floor. The Commission frequently has said that a flat roof cannot serve as a temporary floor if workers must operate along the perimeter of such a roof as it does not рrovide fall protection; either a safety net or one of the alternate safety devices listed in section 1926.105(a) must be used. A reasonable construction company in Corbes-co’s position would have known about these interpretations of this standard. We AFFIRM the citation.
Notes
. An Occupational Safety and Health Administration regulation specifically requires an employеr to furnish a catch platform “below the working area of roofs more than 16 feet from the ground to eaves with a slope greater than 4 inches in 12 inches without a parapet.” See 29 C.F.R. § 1926.451(u)(3) (1990).
. The text of this opinion is not reported, but it is summarized in
Corbesco, Inc.,
. Section 1926.28(a) states that ''[t]he employer is responsible for requiring the wearing of appropriate personal protective equipment in all operations where there is an exposure to hazardous conditions or where this part indicates the need for using such equipment to reduce the hazards to the employees." A similar duty is imposed on all industries by 29 C.F.R. § 1910.132(a). Therefore, the holding of
S & H Riggers
applies equally to citations issued under section 1910.132(a).
See S & H Riggers,
. Adequate notice is particularly important in the construction business becаuse a contractor or subcontractor must be able to predict the cost of required safety equipment when bidding on a project.
See S & H Riggers,
. "A successful economic feasibility argument must demonstrate both that it is extremely costly for the employer to comply with the Secretary’s order and that the employer cannot absorb this cost."
Faultless Div., Bliss & Laughlin Indus., Inc. v. Secretary of Labor,
