biohazard vs biological agent

biohazard and biological agent both are nouns.

Word	Noun	Adjective	Verb	Adverb
biohazard	Yes	No	No	No
biological agent	Yes	No	No	No

As nouns, biohazard and biological agent are synonyms defined as:

biohazard and biological agent: any bacterium or virus or toxin that could be used in biological warfare

biohazard (noun)	biological agent (noun)
any bacterium or virus or toxin that could be used in biological warfare	any bacterium or virus or toxin that could be used in biological warfare
hazard to humans or the environment resulting from biological agents or conditions