On October 27, the US federal Occupational Safety and Health Administration (OSHA) has published an “advanced notice of proposed rulemaking (ANPRM)”, as the first step toward national heat illness prevention rules. This action is the agency’s second recent step to define and combat these hazards – several states already administer such rules. OSHA’s first step was to release new “Inspection Guidance for Heat-Related Hazards” on September 1 (I wrote about it HERE). The remainder of this note summarizes issues raised and questions asked in the ANPRM.