Biohazard's Urban Discipline introduced the band's one-of-a-kind, Brooklyn thrash-rap sound to hardcore fans outside the five boroughs. It's an authentic mix of inner-city vocal rhythms with metal's take-no-prisoners attitude, one that granted them international credibility. Urban Discipline is an original hardcore metal-rap album, debuting a half-decade prior to the rap-rock explosion of the late '90s. It is defiant and distinctive -- in some senses a precursor of bands such as Korn, Limp Bizkit, and the Deftones, and in other ways in a class all its own. It's not the self-indulgent, "I-gotta-get-mine" rap-rock of the late '90s, as it's loaded with social criticism. It's a blue-collar metal record made by rough-shod, tattooed, fighting men. The album's highlight is "Punishment," a hard-charging anthem with a surprisingly melodic chorus. This hook was strong enough to earn them moderate playtime on MTV, even though nothing else sounded like them at the time.Though intended merely as simple music for slam dancing, Biohazard does well to mix things up within those parameters. The group successfully rearranged their typical song structure with divergent bass, drum, and guitar parts in "Shades of Grey." They're technically competent enough to implement light crescendos and decrescendos, tempo variation, and a diffuse focus of the instruments within the band. It's not Mozart, but it is one of the most authentic combinations of thrash and rap ever made.
AllMusic Review by Kieran McCarthy