Cal/OSHA's issuance of the country's first-ever standard on diacetyl, the chemical used in food flavor manufacturing which has been blamed for causing the worker illness known as “popcorn lung,” helps make the case for federal recognition of the state's OSHA program, state agency chief Len Welsh told Inside OSHA Online. Cal/OSHA has been in a long-standing tug of war with OSHA over its bid for federal approval of the state plan, with Welsh urging OSHA to veer from its stance that state plans must essentially mirror federal requirements and instead recognize California's unique regulatory effor
December 30, 2025