In my Process Safety, HAZMAT, and Emergency Response course, I always walk the students through an exercise to demonstrate just how dangerous chemicals such as Cl2 and NH3 are. So many have come to think that these chemicals are only hazardous when we exceed the OSHA/EPA Thresholds for PSM/RMP.
In a space that is 40 ft × 40 ft with an 8ft ceiling, we need only 8 ml/0.00211338 gallons of liquid Cl2 to make the room an IDLH Atmosphere (e.g., 10 ppm). A far cry from OSHA’s PSM TQ of 1500 pounds or EPA’s RMP TQ of 2500 pounds.