NYTimes: Fumes from a waterproofing spray ignited and set off an explosion in the basement of a Brooklyn home yesterday morning, killing a 27-year-old workman and severely burning two others, one of whom staggered out into the backyard in flames.

The blast ripped through the kitchen floor of the three-story home on East 31st Street in Flatlands just seconds after a resident, Tzipora Friedman, walked out of the kitchen into the living room to look at fabric samples with a decorator who had come to the house, according to a cousin who spoke to Ms. Friedman yesterday. Her husband, Joseph Friedman, and their six children were not home.

Fire Department officials said that the man who was killed, Antonio Tapia of Burlington, N.J., and the other two workers were in the basement building a mikvah, or small pool, to be used for ritual baths that Orthodox Jewish women take after their menstrual cycle, before their wedding and after giving birth.

The area was poorly ventilated, officials said, allowing fumes from the spray to build up, although it was not clear yesterday what caused them to ignite. The blast buckled and cracked one side of the house, blew out several of its windows and was strong enough to crack or shatter windows, glass doors and skylights in several other homes. “I heard a big explosion,” said one neighbor, Emmanuel Chevalier, 51. “I felt vibrations, and I heard screaming. I saw a man naked with fire all over his body.” Mr. Chevalier rushed to help put out the fire, pushing the worker to the ground and telling him to roll over, while he grabbed a hose and doused the man with water. “He was bleeding all over � but not from cuts,” Mr. Chevalier said. “His skin was on fire. It was terrible.”

The police said that one of the surviving victims, a 30-year-old man, was taken to Jacobi Medical Center, while the other, 26, was taken to Staten Island University Hospital. Both had severe burns covering large parts of their bodies, and were listed in serious condition late last night.

“It was a powerful blast,” said Robert Byrnes, an acting assistant fire marshal. The department was investigating whether a water heater, power tools or even a light switch might have ignited the vapors. Fire officials said that the spray compound was stored and heated in a truck parked outside the house, and was then run through a hose into the basement, where it was being used to waterproof the bath.

A Fire Department spokesman, James Long, said yesterday that the workers’ employer, J. M. Pereira & Sons, a Langhorne, Pa.-based contractor, had been issued two summonses for storing more than five gallons of flammable liquid without a permit.

Carl Pereira, the owner of the company, arrived at the scene of the explosion yesterday afternoon and said that the workers had been employed by the company for two to five years. “Our prayers are with them and their families,” he added. “It was a tragic work accident, but we don’t know what happened.”

Ilyse Fink, a spokesman for the city’s Department of Buildings, said that the house’s owner, Mr. Friedman, had not obtained a permit for the construction work. The department issued a stop work order on construction at the house.

One of the Friedmans’ children, Menachem, 13, told reporters, “I was at school when someone told me my house exploded,” and he ran home to see what had happened. He told reporters that his mother was unhurt, and that his five siblings � ranging from 5 to 21 � had not been home.

Will Pang, 33, an advertising art director who lives two doors from the Friedmans, said that the blast woke him up.

“It was like a tremor, like a mini-earthquake,” Mr. Pang said. “It knocked down my CD rack in the room. It just shook.” When he walked outside, he said, he saw no flames � only smoke, and smelled a stench like gas. The glass windows on his car were blown out, and the blast dented the door of a garage nearby, he said.

A woman named Devora, 36, who refused to give her last name but said she was a cousin and neighbor of the Friedmans, said that it was “a miracle” that Ms. Friedman had left the kitchen when she did. “God was watching over her,” she said.