A friend pounded on the door of the second-floor apartment of the Guilford Avenue rowhouse, waiting for the family matriarch to emerge for their daily walk. It was 7:30 Tuesday morning, and when there was no answer, the friend gave up and went on her way.
Hours later, police and firefighters responding to a call for people sick on the second and third floors of the three-story red brick house in the 1700 block of Guilford Ave. found two adults dead and three others, including a child, unconscious, apparently the Baltimore area's latest victims of carbon monoxide poisoning.
Fire officials said all five are related. The survivors were rushed to the hyperbaric chamber at Maryland Shock Trauma Center, where authorities said they were in serious condition. Authorities had not released their names or ages Tuesday evening.
Autopsies scheduled for Wednesday should reveal an official cause of death. If carbon monoxide poisoning is found to be responsible, they would be the latest in a recent run of casualties to the odorless, colorless gas that that can be found in combustion fumes, as produced by automobiles or faulty heating systems.
State officials have counted at least 13 accidental deaths from carbon monoxide this year. Confirmation of the suspected poisonings of two men in Pikesville earlier this month and the two victims on Guilford Avenue on Tuesday would bring the total to 17, the most in the state since 2003, when officials counted 21 accidental deaths.
As rescue workers converged on the home shortly after 11 a.m. Tuesday, relatives and friends huddled and cried together outside a church across the street.
"They were a loving family," said friend Collin Knight. He said he last saw them at a Christmas party at a relative's home, and said the mother volunteered at various children's centers.
"Unbelievable," was almost all Melissa Briscoe could utter. She lives across the street and saw the family often, though she didn't know them well.
"I saw her friend come over this morning, as she always did, and look for the lady," Briscoe said. "She knocked and knocked on the door, but when no one came, she left."
Police and other investigators had not found the source of the gas leak by Tuesday evening, though a fire department spokesman said Baltimore Gas and Electric crews were examining virtually any appliance that could produce the gas, including gas driers and water heaters.
Baltimore police homicide detectives conducted the initial investigation, which is routine for unexplained deaths. A police spokesman said that authorities determined by evening that a police investigation was not needed, and the case was turned over to fire officials.
Fire Department spokesman Kevin Cartwright could not say whether the house had carbon monoxide detectors, which is required by law. He said firefighters detected between 300 and 500 parts per million of the gas, lethal amounts. Firefighters are required to wear breathing apparatus when exposed to 35 parts per million;100 parts per million requires immediate evacuation.
Tuesday's deaths came shortly after three adults and three children perished in a wind-swept fire that consumed an East Baltimore rowhouse on Dec. 14, which was two days after two construction workers died from apparent carbon monoxide poisoning in a house in Pikesville.
On Dec. 10, three dozen children and several adults were evacuated from an East Baltimore child care center that filled with carbon monoxide fumes. Five people were hospitalized; officials later blamed the leak on three holes found in a rooftop heating unit.
There have been 86 accidental deaths in Maryland from carbon monoxide poisoning in the last decade. Many more carbon monoxide-related deaths have been ruled a suicide, and one was called a homicide.
In Florida on Monday, five teenagers who had been celebrating a birthday at a motel near Miami died after exposure from carbon monoxide from a car they had left running in a garage under their room.
On Guilford Avenue, close relatives of the victims were too distraught Tuesday to talk. They gathered in clumps, sobbing into cell phones and into one another's shoulders. One woman knelt in the vestibule of a vacant building, crying on her knees. Others shouted, desperate for any shred of information.
They were angry with fire officials and police who didn't tell them much, even the gender of the victims, whose bodies were still in the house two hours after they had been found, and they appeared angry with one another.
At one point, a man in a hooded sweatshirt cried, "That's my mom!" as relatives tried to both restrain and console him. Two police officers pushed him across the street and into a wall as family members rushed after him. Finally, after several minutes, a friend's grip replaced the hold of an officer's, and both men collapsed against a church wall in tears.
A minister of the New Second Missionary Baptist Church across the street from the house opened the warm rectory to grieving relatives. Police later took them to Shock Trauma to be with the survivors.
The rowhouse, assessed at $55,000, is owned by Greater Baltimore AHC Inc. of Arlington, Va., which owns more than 1,000 apartments in Baltimore.
A spokeswoman for the company said she did not know how carbon monoxide would have entered the apartment, or whether it had a carbon monoxide detector.
Baltimore Sun reporter Meredith Cohn contributed to this article.