In 1990, following years of mostly uneventful parties, the police presence was removed. The Mifflin Street Co-op hired four off-duty police officers, and the event went off peacefully.
However, in 1991 the city cracked down on alcohol concessions at block parties, requiring the Co-op to limit alcohol to an enclosed beer garden. The co-op decided not to organize the block party that year, fearing it would lose money. Houses hosted parties anyway with bands performing on porches, though police prohibited open alcohol on public sidewalks and streets.
In subsequent years, the block party continued to be a collection of house parties with no permits or notice given to city officials.
The party became more structured in 1994 and 1995, with bands being booked by promoters including Black-n-Tan Productions, Paramount Nightclub owner Gary Taylor and Phil Meier. The 1994 event, the 25th anniversary, drew 25,000 people. That year, two people died nearby in alcohol-related crashes and a woman was sexually assaulted.
On May 4, 1996, the party devolved into chaos after revelers set bonfires in the street and threw bottles and rocks at firefighters who tried to douse the flames. Twenty-two people were injured, including 11 police officers and a firefighter. Thirty-three police officers were at the scene when the bonfires started. Eight people were arrested.
The police presence was much higher for the rest of the decade and the party was once again not sanctioned by the city. There was no repeat of 1996's violence, but police continued to cite partygoers for alcohol and drug-related crimes.