Central Ac Smell Like Sulfur and Phosphorus

by Tasha L
(Gaithersburg, Md, USA)

I live in an apartment on the bottom floor. Recently, I have notice when I turn on the central ac a FOUL smell would comes from the vents. It smell somewhat like sulfur/phosphorus mixed with sewage.

When I contacted my landlord, the maintenance men said "It's just mildew nothing serious"..I've smelled mildew, unless there's a mildew I'm unaware of, this does NOT smell like mildew...stagnant water MAYBE.

We do not have access to the central ac unit itself since it is locked behind a "closet" door in the house. I don't have much more information than how bad the smell is, it came on kind of suddenly, does NOT smell like a dead animal or anything.

As close as I can call it was sulfur/phosphorus....ANY suggestions would be welcome (fyi: our filter was recently changed so I don’t believe it would be that) also I was told that if it is mold or stale water, isn't this true that this can be harmful to your health to be breathing such fumes?

Thank You

Tasha L