A tenant of one of the two New York apartment buildings flattened by a massive explosion said residents had complained repeatedly in recent weeks about "unbearable" gas smells.
The blast in Harlem on Wednesday morning killed at least seven people and injured more than 60. Five people remained missing, New York police detective Martin Speechley said.
Rescuers working amid billowing smoke pulled four additional bodies yesterday from the rubble, with searchers still trying to locate others a day later.
Heavy equipment, including backhoes and a bulldozer, arrived to clear the mountain of debris where the two five-storey East Harlem buildings had stood. Thermal imaging cameras were at the ready to identify heat spots - bodies or pockets of fire.
The recovery effort was hampered by bad weather, with rain and temperatures below freezing. Some parts of the debris pile were inaccessible because of a sinkhole caused by a subsurface water-main break.
Tenant Ruben Borrero said residents had complained to the landlord about smelling gas as recently as Tuesday.
A few weeks ago, Borrero said, city fire officials were called about the odour, which he said was so bad that a tenant on the top floor broke open the door to the roof for ventilation.
"It was unbearable," said Borrero, who lived in a second-floor apartment with his mother and sister, who were away at the time of the explosion. "You walk in the front door and you want to turn around and walk directly out."
The fiery blast, in Park Avenue at 116th Street, not far from the edge of Central Park, erupted at about 9.30am.
The explosion shattered windows a block away, rained debris onto elevated commuter railway tracks close by, cast a plume of smoke over the skyline and sent people running into the streets.
"It felt like an earthquake had rattled my whole building," said Waldemar Infante, a porter who was working in a basement nearby. "There were glass shards everywhere on the ground, and all the stores had their windows blown out."
The fire department said a check of its records found no instances in the past month in which tenants of the two buildings reported gas odours or leaks.