On December 22, 2017, the U.S. Court of Appeals for the District of Columbia Circuit issued a unanimous opinion upholding most of the Occupational Safety and Health Administration’s (OSHA) 2016 revised workplace standard for respirable crystalline silica, 29 C.F.R § 1910.1053(a)(1). The case is North America’s Building Trades Unions v. OSHA. The new rule lowers by half the permissible exposure level (PEL) of a worker’s exposure during the workday for all covered industries including the foundry, brick, construction and hydraulic fracturing industries.

Briefly, the rule requires employers to assess silica exposure levels in the workplace and, if necessary, implement engineering and work practices to keep the exposure levels below the new standard. If these measures are unsuccessful, then the rule provides that employees must take other steps, as well as adhere to new housekeeping and medical surveillance requirements. The rule established different compliance dates for the construction industry (June 23, 2107), the foundry industry (June 23, 2108), and the hydraulic fracturing industry (June 23, 2012).

Under the rule, OSHA’s significant risk, technological feasibility and economic feasibility findings are governed by the law’s “substantial evidence” standard. After reviewing the record and the arguments of the parties, including those of the Intervenor Chamber of Commerce, the Court of Appeals had little difficulty is holding that OSHA’s findings are supported by substantial evidence and were upheld.

The Union petitioners also challenged the rule, and the Court of Appeals agreed that OSHA’s Medical Removal Protection standard was arbitrary and capricious, and will be remanded to OSHA for reconsideration or a more complete explanation.