Two of the most dangerous street gangs of East L.A., Il Grande Hazard and MC Forceros, called a truce to allow director Edward James Olmos to shoot the movie on their turfs.
According to 60 Minutes (1968), three people who acted as consultants on this film were later murdered because of the depiction of a homosexual rape scene that reportedly deeply offended the Mexican Mafia's machismo. The victims were: Charles Manriquez (known as Charlie Brown), a Mexican Mafia member and unofficial consultant to the film, killed on early 1992; actress Ana Lizarraga, a community youth counselor and official consultant to the director who was shot in her driveway in front of her son and her boyfriend; and Manuel Luna (known as Rocky), a former gang member who also worked as consultant, killed a year after the film's release.
William Forsythe had a big gap in middle of his teeth, Steve Wilcox who plays the young JD had to put on prosthetic teeth so he could look exactly like Forsythe's teeth.
Most of the extras who were dressed as prisoners quit after the first day of filming. They were kept in a gated area next to an open sewer and had to ask guards to use the bathroom. Guards are used to ignoring prisoners, so they mostly ignored extras dressed as prisoners. They weren't given enough water and lunch wasn't served until late in the day. Conditions slightly improved on the second day, but on the third and final day of filming at Folsom Prison there were about 25 of the 200 that showed up on the first day.
Danny Trejo said Olmos lied about getting permission to make the movie. Trejo had a phone conversation with the real-life JD (Joe "Pegleg" Morgan) and he asked him if Olmos ever got permission to make the movie and Morgan replied saying "No, I didn't give him permission to make the movie."