DC 33 President Pete Matthews said Nutter was not asked to address the group. He said members, who have been without a contract since July 2009, are frustrated.
"A leader leads," Matthews said. "The mayor dictates and that's his problem. They're totally frustrated with him ... The last two budgets have been balanced off the backs of city workers."
Nutter's campaign spokeswoman, Sheila Simmons, called DC 33's decision embarrassing to the union.
"It's irresponsible of the DC 33 leadership to encourage its members to support a candidate who owes the city $388,000 in taxes right now instead of encouraging them to support a candidate through whose leadership the city has been able to close a $2.5 billion deficit without any major layoffs and without any major cuts in services," she said.
The city's chief union negotiator, attorney Shannon Farmer of the Ballard Spahr law firm, said Nutter was not trying to dictate contract terms to the unions.
"The city has come to the table and been very clear about its financial situation and that it needs to achieve overall savings in pension and health care and get a contract that we can afford," Farmer said. "Obviously we would like there to be a contract as well."
Gault described as "colorful history" the recent events in Street's life - declaring bankruptcy in 2005, serving 26 months in federal custody for not paying taxes and still owing $1.1 million in back taxes to the federal government, New Jersey and Philadelphia.
Gault's comments focused more on Nutter than on Street, complaining again about the closure of five engine companies and two ladder companies, the "brownouts" of some stations taken out of service temporarily and disputes on contract matters.
Nutter yesterday reacted by saying he has "the utmost respect" for city firefighters. "That's the wonderful thing about America: It's a free country and folks can endorse anyone they want," he said. "I am a tremendous admirer and supporter of firefighters in the city of Philadelphia."
Street vowed that if elected he'd seek federal grants to immediately hire 100 firefighters. Gault said he believed Street could make it happen.
"He has the ability," Gault said. "He'll find the money."
Street is running an unconventional campaign, raising little money to pay for advertising, relying instead on sheer footwork.
Street rejected suggestions that the firefighters were using him to target Nutter.
"They understand that I am a conceptualizer, that I can come up with solutions," he said.
Gault said the endorsement was the source of "lots of debate" among union members at a meeting last week, with some seeking to back a Republican while others didn't want to back anyone. Gault said the endorsement would at least get people thinking again about the union's complaints.
District Council 47, the city's white-collar union and also without a contract, has also been critical of Nutter for not engaging in contract talks. DC 47 will hold a delegate assembly on April 26 to consider endorsements; both candidates are invited to speak.
The local Fraternal Order of Police chapter has chosen not to make an endorsement. And although the lack of union backing speaks to labor's overall lukewarm feelings for Nutter, FOP President John McNesby noted this isn't expected to be much of a race.
"There's really not a race and there's not going to be," he said. "Nutter's in a championship fight with a sparring partner."