Just as with chlorine gas: Luckily, we're incredibly sensitive to the odor of even safe-ish trace quantities of the toxin, so the actual risk is dramatically mi

Just as with chlorine gas: Luckily, we're incredibly sensitive to the odor of even safe-ish trace quantities of the toxin, so the actual risk is dramatically mitigated in any environment where there's air mixing. Smell it, back away until you can't smell it, and you're a survivor. Just don't, say, descend an elevator shaft into an un-ventilated sub-basement with ammonia storage. The amount of inconsequentially small ammonia leaks which nevertheless the owner insists on a service technician fixing immediately because of the alarming odor, actually form most of the case against ammonia as a refrigerant, which it's otherwise well-suited to.