Biohazard was one of the first bands to regularly incorporate elements of both hip-hop and hardcore metal into their sound; since their lyrical fare dealt with the harshness of urban life and the resulting anger and frustration, which both genres of music have been known to address, the connection only made sense, especially in light of Anthrax's highly effective collaboration with Public Enemy on 1991's "Bring the Noise." When Biohazard formed in 1988 in Brooklyn, NY, their sound was much closer to the former band than the latter; their original lineup consisted of guitarist/vocalist Billy Graziadei, bassist/vocalist Evan Seinfeld, guitarist Bobby Hambel, and drummer Danny Schuler. They began opening for local hardcore and thrash bands and gradually built a large following through their outraged sense of injustice, political awareness, and constant touring. A self-titled debut was released in 1990 on the Maze label, but by 1992, Biohazard's fan base was strong enough to secure a deal with Roadrunner Records.

Their subsequent breakthrough album, Urban Discipline, built on the groundwork laid by "Bring the Noise," laying rhythmically shouted vocals over heavy, hip-hop-influenced beats and guitar riffs recalling both hardcore and thrash. The hardcore rap group Onyx recorded an alternate version of their hit single "Slam" with Biohazard backing them, and the two groups worked together again on the Judgment Night soundtrack, contributing the title song. 1994's State of the World Address solidified both their reputation for intensity and their musical hybrid, but Hambel then left the band, reducing them to a trio for 1996's Mata Leao, which some found the group's most seamless rap/metal fusion yet. Hambel was eventually replaced by ex-Helmet guitarist Rob Echevarria, and in 1997, Biohazard released the live album No Holds Barred, which showcased the in-concert ferocity for which the group had become revered.

Biohazard next signed to Mercury Records and released New World Disorder in 1999. The guys left the label following its merger with Universal and harkened back to their D.I.Y. days with a tour of Europe and Japan without label or managerial support. The rarities collection Tales from the B-Side followed in 2001, along with their next full-length, Uncivilization. Guitarist Leo Curley exited the group following the album's release. Kill or Be Killed appeared two years later and featured new axeman Carmine Vincent (ex-Nucleus), who had previously roadied for the band. Means to an End, Biohazard's eighth and final album, was issued in August 2005 on SPV. Graziadei went on to form Suicide City with ex-members of Groovenics and Kittie. Meanwhile, Seinfeld appeared on the 2006 VH1 reality show Supergroup with Ted Nugent, Sebastian Bach, Scott Ian, and Jason Bonham. In December of 2007, a live double-disc CD and accompanying DVD titled Live in San Francisco was released, documenting, what was said to be, one of their last shows together as a band.
However, unexpectedly Biohazard re-unites in the beginning of 2008. Bobby Hambel who has been in conflict with the rest of the original members for over 10 years has rejoined the band.
Biohazard immediately hit the road doing single shows in USA, a mini-tour with Chimaira, Korn and Throwdown (Australia, New Zealand, South America) and some festivals in Europe (including With Full Force 2008).
During fall and winter of 2008 Biohazard performed a complete "20th Anniversary" European tour giving around 40 shows. The year 2008 ends with single shows in Japan and USA (with Harley's War and Life of Agony). Rumors about new Biohazard album are becoming more and more possible.

In 2012 Biohazard released their highly anticipated original line up album Reborn In Defiance (produced by Toby Wright). This release marks the end of the original Biohazard line up as Evan decides to leave the band just before finishing the album. He's replaced by Scott Roberts who joins for the Reborn In Defiance world tour. In early 2012 Biohazard hits East Coast of the US (with Madball and Sworn Enemy) and western Europe with Persistence Tour (with Suicidal Tendencies, Terror and Walls of Jericho). Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.