HOUSTON -- A shelter-in-place warning in the Cy Fair area in northwest Harris County was lifted early Sunday after a four-alarm fire that left several firefighters injured, KPRC Local 2 reported.

The blaze broke out at Ram Chemical and Supply Inc., 4949 Greenhouse Road, at about 2:45 p.m. Saturday.

Hazardous smoke continued to pour out of the swimming pool chemical factory for hours.

The fumes endangered those in nearby subdivisions, according to firefighters.

Larry Alsobrook said he was one of the first to see the fire and dialed 911.

"I mean orange flames blowing probably 100 feet in the air," he said. "I mean the whole back of the warehouse was going. I was like 'That's a chemical company? We're getting out of here.'"

A spokesman with the Cy-Fair Volunteer Fire Department said the fire spread from the front warehouse to the rear warehouse, eventually overtaking the building's office space and spawning several grass fires that were quickly contained.

Alsobrook said he was concerned that someone might be trapped inside.

"There was a blue truck sitting there with all of their big trucks," he said. "We thought somebody had an accident and they're still in the building."

Firefighters said no one was believed to have been inside during the fire.

Out of precaution, CFVFD called for a shelter in place, asking folks in the Meadow Woods subdivision to keep their houses closed up from toxic fumes.

"There's obviously a lot of chlorine a lot of acids in the warehouse," CFVFD spokesman Robert Rasa said. "We're just wanting people to have their windows and doors closed until the smoke clears. It's just precautionary at this time."

Doug Hanks said said he does business with one of the owners and said he could not believe what he was seeing.

"(It's) very sad," he said. "I'm in the pool business and we've known (the owner) for quite some time. We buy our stuff there on a regular basis."

A Cy-Fair spokesman said the shelter- in-place continued overnight. It was lifted early Sunday morning.

Fire officials said there were a total of five injuries. All of them were firefighters.

Most of the injuries were from smoke inhalation. One fire fighter had to be taken to the hospital. His condition was not released.