Remove dangerous substances from (13)
I believe the answer is:
decontaminate
'remove dangerous substances from' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for decontaminate that I've seen before include "Remove the bad" , "Purify; make safe" , "Remove pollution from" , "Remove dangerous substance from (something)" , "Remove dangerous substances from" .)