NEW YORK (CBSNewYork/AP) -- Firefighters were still battling a massive warehouse fire Sunday morning in Williamsburg, Brooklyn.

The seven-alarm blaze started Saturday morning. More than 24 hours later, thick smoke could still be seen pouring out of the building.

A fireboat was also trying to help from the water.

It could take at least a week to put the fire out, CBS2's Ilana Gold reported. In the meantime, neighbors are concerned about their safety, worried the fire is going to spread as well as the effects of the smothering smoke and floating ash on their health.

Some people were covering their faces to avoid breathing it in.

"We were concerned why it hasn't been constrained," said Britany Gray, of Williamsburg. "I mean, it's taken so many hours for them to put out the fire."

The city Health Department is advising anyone who lives near the fire or downwind of it to stay inside and keep windows closed.

Health officials say air quality has been affected, and people with respiratory ailments may have difficulty breathing.

Firefighters initially responded to a small fire in the storage facility at 4:30 a.m. Saturday, extinguished the blaze and then left.

But then they got called back an hour and a half later, and the building was engulfed in flames.

The industrial building near the East River was stacked floor to ceiling with boxes of records. According to The New York Times, the state court system, the city Health and Hospitals Corp., and member hospitals of the Greater New York Hospital Association all had records stored at the warehouse.

The paper inside the building has fueled the inferno.

"Tremendous amount of flammables," said James Leonard, FDNY chief of department. "This type of building, too, once that paper starts burning, it's very difficult. It burrows in."

The weather has only made matters worse for the nearly 300 firefighters battling the blaze. The fierce wind has also carried the flames. And from the uniforms to hoses and hydrants, everything keeps freezing up, making the situation even more dangerous.

"Especially the firefighters in the tower ladders are extremely, extremely exposed," Leonard said.

"I can't believe they're out here doing this right now," one woman said. "It's freezing."

Firefighters say they're hoping to get a good handle on the flames later Sunday, now that the wind has died down.

No serious injuries have been reported. One person was treated for smoke inhalation.

The cause of the blaze is still under investigation.

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