Extremely destructive drug found in storage facility (5)
I believe the answer is:
depot
'storage facility' is the definition.
'extremely destructive drug' is the wordplay.
'extremely' means to remove the middle letters.
'drug' becomes 'pot' (slang term for cannabis).
'destructive' with its middle taken out is 'de'.
'de'+'pot'='DEPOT'
'found in' acts as a link.
(Other definitions for depot that I've seen before include "Place where buses and trains are kept" , "Wherein bus drivers" , "Terminus for transport vehicles" , "Storehouse or warehouse" , "Storehouse as for supplies" .)