This year’s campaign for New York City mayor was expected to turn on police tactics, education policy and economic development.
On Thursday, six of the leading candidates in the race found themselves discussing something different: mold.
The hazardous fungus, and its proliferation in homes and neighborhoods damaged by Hurricane Sandy, took center stage at a Brooklyn church during a forum on housing policy, an early clash in a race whose candidates are still looking for ways to stand out.
When a Brooklyn homeowner raised concerns about toxic mold buildup, Bill de Blasio, the public advocate, used the opportunity to compare Mayor Michael R. Bloomberg’s storm response to President George W. Bush’s raising a “Mission Accomplished” banner during the war in Iraq.
“The city likes to say the crisis is over,” said Mr. de Blasio, a Democrat. “We will treat this as a public health crisis, because it is a public health crisis.”
Tom Allon, a Republican hopeful who is rarely invited to appear alongside his better-known Democratic rivals, criticized the health department for “chasing after people who are drinking 32-ounce soft drinks” instead of looking at health problems related to the hurricane.
But John C. Liu, a Democrat who is city comptroller, earned the loudest laughter of the night with his reply: “It’s quite possible that Mayor Bloomberg doesn’t know what mold is.”
The forum, sponsored by The Daily News and the Metro Industrial Areas Foundation, a community activist group, touched on troubles with public housing and the plight of working-class New Yorkers facing higher housing costs.
But in a race in which the ideological spectrum is notably narrow — even one of the Republicans supports legalizing marijuana — the stylistic differences among the candidates stood out, as each turned to personal histories and community ties as selling points for the predominantly black crowd.
William C. Thompson Jr., a former city comptroller, made sure to mention that his mother once led a Brooklyn agency for the aging. Another Democrat, Christine C. Quinn, the City Council speaker, emphasized her experience with housing and described her immigrant grandfather, a firefighter, eking out a living with the help of a rent-controlled apartment in Upper Manhattan.
The event was the first time that Joseph J. Lhota, former head of the Metropolitan Transportation Authority, appeared publicly with the other mayoral candidates since he entered the race as a Republican this month.
Despite his reputation for bluntness, Mr. Lhota was relatively subdued in his remarks, discussing the minutiae of New York’s housing bureaucracy and appearing every bit the budget director that he was in the Giuliani administration.
Mr. Lhota’s most surprising moment came toward the end, when he suggested that the city help pay for housing improvements by creating retail spaces for delis and dry cleaners in public housing complexes. That idea drew a tepid response.
The audience seemed more impressed by Mr. Thompson’s proposal to throw out the current Housing Authority board and replace it with a system allowing more direct accountability to the mayor.
Mr. Allon came prepared with zingers, criticizing John B. Rhea, the public housing chief. His praise for former Mayor Edward I. Koch, a divisive figure for many black residents, however, drew a cooler response.
The stormiest words came from Mr. de Blasio, who has made “tale of two cities” a rallying cry of his campaign events. On Thursday, he worked to channel the frustration of New Yorkers who find it “hard to make ends meet,” and he suggested that biases among House Republicans had led to less federal money for urban housing programs.
Ms. Quinn cited several programs she had put in place as speaker to improve housing options in the city. And she directed some light criticism toward her usual political ally, Mr. Bloomberg, poking fun at his idea to build micro-unit apartments for young professionals, calling it “a contest to build itty-bitty housing on the East Side of Manhattan.”