Help me help my employee!
For privacy, I won't go into details, but I work in an old building, in an office-type environment. We have an employee, D, who has been with us for just under a year. On Saturday, D came in and suddenly started breaking out in hives, and their lips swelled up. I was very concerned and asked D if they would like to go home, but they said they were fine and took a Benadryl. The symptoms went away quickly after taking it. I followed up with D to make sure they were OK, and they didn't have any other symptoms over the weekend. They also stated that they hadn't tried any new foods, taken any medications, etc. They told me this only happened one other time and it was a reaction to a medication.
This afternoon, D came in to work for the first time since Saturday. Within 15 minutes, they broke out in hives. They immediately took a Benadryl and again insisted they were fine. Obviously, I am going to look into OSHA regulations, etc., but I am curious if anyone has any idea what might be causing this? D worked on Thursday and nothing at all happened. Then they walked in two days later and suddenly they're very allergic to something in the building. I checked with our custodian, and no new cleaning agents or air fresheners have been used. There is no obvious mold in the area, and the AC has been running here for about a month and a half, so it doesn't seem likely that something would very suddenly be in the vents.
We are in a semi-rural area with no industrial plants. There is a grain silo a couple of blocks away, but it's not really in use this time of year. Because of the age of the building, I wonder about mold, but wouldn't that have been more of a gradual process? I can't wrap my head around mold growing to that extent in less than 48 hours. I clearly need to check the building for allergens, but I just don't know where to start. Help!