35 years ago I worked in a cleanroom making computer chips. We had a machine that ran phosgene and were told that if we ever smelled garlic or saw anyone falling over by that machine to evacuate immediately and yell at our supervisor on the way out. For a while, the 3 of us running it could smell very faint garlic and were constantly nauseated.

Phosgene is supposed to be violently poisonous in very small quantities. Just mentioning it because the odor sounds similar.