biological agent vs biohazard

biological agent and biohazard both are nouns.

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

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

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

biological agent (noun)	biohazard (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