Legal: airborne allergens/Chinese food?

My dad is running a facility for teaching severely mentally and physically disabled students. Some of them have myriad health problems, including diminished immunodeficiency.
The facility is next door to a Chinese restaurant. Shortly after the facility opened, one of the teachers had to go home with a severe allergic reaction to something in the air. From what I’ve been able to come up with, peanut oil, garlic, MSG and several other ingredients in Chinese cooking can lead to severe allergic reactions; even particulate matter in, say, cook-smoke.

I’m trying to find out if this kind of reaction to the fumes from the restaurant - which was there when they leased the facility - can be grounds for breaking their lease. The teacher’s reaction is scary, but he’s (my dad) most worried about the possible reactions in the children.