Chancellor Dennis Walcott addresses P.S. 51 parents.

Admitting that they had responded too slowly to news of toxic chemicals at a Bronx elementary school, Department of Education officials said the city would accelerate environmental testing of leased school sites.

At a public meeting tonight for people who attended or worked at P.S. 51, which was shuttered two weeks ago over concerns about toxic chemicals detected there, Schools Chancellor Dennis Walcott announced that the city would complete reviews of 31 sites where leases are up for renewal by the beginning of September.

The announcement comes after mounting criticism of the way the department’s has dealt with toxic chemicals in schools, especially PCBs found in older light fixtures. A nonprofit law firm, New York Lawyers for the Public Interest, announced yesterday it planned to sue the DOE over the fixtures on behalf of New York Community for Change, a parent organization.

Hundreds of anxious P.S. 51 parents and students, past and present, came to the Bronx High School of Science tonight to learn more about safety concerns at the school.

Walcott also revealed where P.S. 51′s 225 current students would attend school next month. They will be bused two miles to a Catholic school building, St. Martin of Tours on East 182nd Street, where P.S. 51 will be the only school on site, he said.

Walcott also apologized repeatedly for the DOE’s slow response to the safety concern. The city detected unsafe levels of a toxic chemical at P.S. 51 six months ago, before Walcott became chancellor, but did not disclose that fact to families until this summer.

“I own this,” Walcott said. “I am the chancellor, and I will take full responsibility for this.”

Walcott said there might be a silver lining to the move: St. Martin’s has a gym and an auditorium, which P.S. 51′s building lacked.

But that information came as little consolation to parents who said their children have demonstrated symptoms of exposure to the chemical, trichloroethylene.

Cynthia Rodriguez said her daughter, Erin Arroyo, frequently complained of headaches, dizziness, and sinus problems while attending second grade at P.S. 51 last year.

“There are a lot of symptoms which almost all of our children have,” she said, eliciting applause and murmurs from the audience.

In large doses, the chemical has been linked to cancer and kidney failure. The United Federation of Teachers has asked the city to provide medical screenings for teachers who worked in the school, which had occupied the Jerome Avenue building for nearly two decades.

“They should have notified us in February,” Rodriguez said in an interview. “They’re saying they’re going to give all the information to us, but I didn’t even receive a letter about this meeting.”

She said news of the public meeting circulated by word of mouth among her parent friends.

Word of mouth brought Leona Johnson to the meeting. Her daughter, now 24, attended P.S. 51, she said, and she is concerned that her daughter’s ovarian cysts were caused by exposure to trichloroethlyene.

Johnson was one of several parents who said they were not satisfied with the Department of Health and Mental Hygiene’s answers to questions about how students might have been affected by exposure over the long term.

Nathan Graber, DOHMH’s director of environmental and occupational disease epidemiology, said city officials are concerned about trichloroethylene’s cancer-causing properties but have not yet determined the cancer risk at P.S. 51. He said the city intends to develop a registry of people who spent time in the building but said families and teachers should take concerns to their doctors for now.