Which of the following is NOT an OSHA regulatory limit for anhydrous ammonia?

The OSHA regulatory limits for anhydrous ammonia are established to protect workers from the potential hazards associated with exposure to this chemical. The permissible exposure limit (PEL) set by OSHA for anhydrous ammonia is 50 parts per million (ppm) averaged over an 8-hour work shift.

The first choice of 25 ppm is actually lower than the established PEL, serving as an exposure level that may be considered for more sensitive individuals or specific situations but is not a regulatory limit. The 50 ppm is indeed the limit under OSHA regulations for an 8-hour time-weighted average. The choice of 35 ppm does not represent an OSHA regulatory limit either, but might reflect other recommendations or industry standards that recognize lower exposure levels.

The choice of 100 ppm exceeds the established occupational exposure limit, and therefore does not conform to OSHA guidelines, specifically indicating levels that could be dangerous if exposure occurs. Thus, within the context of the question regarding regulatory limits, the correct answer is the 100 ppm option, as it is not recognized as a permissible occupational exposure limit for anhydrous ammonia under OSHA regulations.