The E1.23 document offers advice on the planning and execution of theatrical fog effects using glycol, glycerin, or white mineral oil fogs or mists in theatres, arenas, and other places of entertainment or public assembly. The revision project is to (1) change the list of fog chemicals in the scope to better match those chemicals normally used in theatrical fog effects, and (2) to better define the qualifications of those in charge of designing and executing the effects.