The Occupational Safety and Health Administration may have thrown in the towel on issuing a general industry regulation for combustible dust before the end of the Obama Administration in January 2017.

The clearest sign: A schedule for releasing the proposed combustible dust rule has been wiped from the latest regulatory agenda, released last fall. The agenda commits the agency only to putting together a small business forum, referred to as a SBREFA panel, in August 2016. Even that is in doubt, according to one industry insider.

“The notion that they’re going to begin SBREFA in August is pretty hard to imagine,” Marc Freedman, Executive Director of Labor Law Policy at the U.S. Chamber of Commerce, told Bloomberg BNA on January 11. “And the idea that they’d get a proposed rule out this year ... that would be a heavy lift.”

Freedman noted that dust-related deflagrations and explosions have many possible causes, making it hard to develop a responsible regulation. “It’s not an intrinsic hazard; it’s created by multiple factors that differ by substance and setting,” Freedman told the news service. “In order to create a standard around combustible dust, it will take a lot of work. And I imagine not a lot of people at OSHA are excited about this, particularly this late in the administration.”

In fact, the complexity of a regulation on combustible dust may have caught the agency by surprise. “This does not appear to be a priority for OSHA like it once was,” said Jess McCluer, Director of Safety and Regulatory Affairs for the National Grain and Feed Association (NGFA).

“It did appear to be a priority at the beginning of the administration, but after understanding the complexity it seems to have moved to the side. And other issues have moved to the top of the priority list,” he told Bloomberg BNA.

The robust agenda to which OSHA has committed itself in 2016 also may have played a part. The agency has set dates early this year for release of major rules on crystalline silica (February), improving tracking of workplace injuries and illnesses (March), and walking-working surfaces and personal fall protection systems (April). Although it has yet to set a date for a final rule, OSHA also is moving forward on a comprehensive rule for beryllium.

The agency implemented a National Emphasis Program on combustible dust in March 2008 and has issued several guidance documents. An advanced notice of proposed rulemaking came out in October 2009, followed by a series of stakeholder meetings, ending in April 2010. OSHA also convened an expert forum in May 2011, but, aside from a May 2015 enforcement guidance document, there has been little movement since then.

Still, since dust explosions continue to injure workers and damage property, OSHA has not been entirely inactive. In the face of a prolonged regulatory process with an uncertain outcome, the agency has turned to other approaches to address the risks. During the process of amending its Hazard Communication Standard to comply with a Globally Harmonized System for Classifying and Labeling Chemicals (GHS), OSHA classified combustible dust as a hazardous chemical. The designation was challenged by industry, but in 2014, the D.C. Circuit Court of Appeals upheld OSHA’s classification. Now, the agency is moving to insert a chapter on combustible dust into the GHS, NGFA’s McCluer told Bloomberg BNA.