Even having worked with hazmat and having worn gas masks, I hadn't heard the phrase "hazmat mask".
But -- as it turns out -- the phrase is in use. And there are people advertising in Google.
Pitch it to the end users and see if anybody wants to buy. If it sells, I'd expect it to sell between $250 and $1500.
I don't think sales will pick up on account of Ebola. Hopefully they won't.