A prudent person would certainly hope the people responsible for procuring this "MHS" actually knew the difference between "contaminates" and "contaminants."
con·tam·i·nate
[v. kuhn-tam-uh-neyt; n., adj. kuhn-tam-uh-nit, -neyt]
noun
3.
something that contaminates or carries contamination; contaminant.
One could argue that maintainers of online dictionaries rush to canonize common grammatical errors, I suppose.
So does the open drop-seat trousers of the LGBTwhateverwhatever
It is possible he said contaminants and the reporter typing it in later didn’t know the difference so misspelled it.