WAXAHACHIE, Texas (AP) -- A fire sparked as workers mixed chemicals at a plant south of Dallas shot massive plumes of black smoke and bright orange flames into the sky Monday, forcing schoolchildren and residents to evacuate or take cover indoors to avoid possible exposure to dangerous gases.
Flames engulfed a large complex at a Magnablend Inc. facility in Waxahachie. The fast-moving blaze overwhelmed a sprinkler system and consumed a fire truck, but no injuries were reported from the fire or resulting smoke.
Waxahachie Fire Chief David Hudgins said it wasn't immediately clear what chemicals were involved in sparking the fire.
About 1,000 residents who had been evacuated were allowed to return to their homes early Monday evening, said Waxahachie Fire Department spokeswoman Amy Hollywood. Waxahachie, 30 miles south of Dallas, has about 25,000 residents.
The blaze was 95 percent under control by early Monday evening, Hollywood said.
In a statement, the U.S. Environmental Protection Agency said it has monitored air quality both on the ground and through a specially equipped airplane that made several passes through the smoke plume caused by the blaze and officials have not found elevated levels of toxic chemicals. The EPA said it "will continue to conduct ground level air monitoring."
Magnablend spokesman Donald Golden told WFAA-TV that 25 to 30 employees who were inside the plant's 100,000-square-foot warehouse evacuated safely when the fire broke out before 11 a.m. Golden said the company manufactures about 200 products, including some that are hazardous when ignited.
Authorities had ordered residents closest to the plant to evacuate, while others were advised to stay inside with doors and windows shut.
Jessenia Colin, an assistant general manager at a nearby Hampton Inn and Suites, said hotel staff members turned off air vents so smoke and chemicals didn't enter the rooms. As they waited for news and watched the smoke billow, staff covered their mouths to protect against the heavy chemical smell that hung in the air.
"It smells like a whole bunch of chemicals, like wrappers burning," Colin said. "It's making everyone's heads hurt."
Stephanie Otto said she was preparing her new restaurant for a Tuesday opening about a quarter-mile from the plant when she heard sirens and walked outside to see a "huge plume." She said she could hear what sounded like gun shots for about 15 minutes, and there was a strong smell of ammonia.
"It was huge," Otto said. "It looked like an atomic bomb went off."
Ellis County emergency management officials had issued a mandatory evacuation order for an apartment complex, an elementary school and a junior college. Sheriff's officials had urged residents not to drive toward the area of the fire.
Magnablend Inc. manufactures, blends and packages chemicals. Much of its business revolves around energy production, including chemicals used to stimulate oil and gas wells and hydraulic fracturing. The company was launched in Waxahachie in 1979 and now employs about 250 people, with operations in Pennsylvania, Wyoming and North Dakota as well as Texas.
Texas Commission on Environmental Quality spokeswoman Lisa Wheeler said Magnablend has been in compliance with its state permits. A search of public documents revealed no significant violations for the company.
Associated Press writers Schuyler Dixon and Danny Robbins in Dallas, Ramit Plushnick-Masti in Houston, Juan Carlos Llorca in El Paso and Jennifer Garske at the Broadcast News Center in Washington contributed to this report.