Question: what is tlv of h2s?
Answer: ACGIH® recommends a threshold limit value (TLV®) of 1 ppm as an 8-hour time weighted average (TWA) and a short-term exposure limit (STEL) of 5 ppm. 29 CFR 1910.119 App A, List of highly hazardous chemicals, toxics and reactives (mandatory).