(CNN) -- One person was killed and another injured in a chemical plant explosion late Thursday near Charleston, West Virginia.

Sterling Lewis Jr., West Virginia's fire marshal, told reporters Friday morning that a helicopter took the injured person to a burn unit in Pittsburgh, Pennsylvania.

Several thousand people were ordered to stay indoors for safety early Friday after the 10:30 p.m. Thursday blast at the Bayer CropScience plant raised fears about air quality. The plant produces crop-protection chemicals in Institute, an unincorporated community in Kanawha County, West Virginia.

Jeannie Young, 38, turned off air conditioners, closed vents and taped windows shut at her St. Albans home after the nearby explosion.

"My daughter and I have headaches," Young said.

She said she smelled something unusual and noticed something odd after taking her three dogs out around 11 p.m. Thursday.

"They acted really funny," she said. "They wanted to come right back in the house." Watch how the plant blast puts a scare into West Virginians »

Young endured a few hours of anxiety with her 15-year-old daughter, Brittney, as authorities closed parts of Interstate 64 and fought a blaze at the plant.

"It was, like, really scary at first," Brittney said.

Emergency officials in Kanawha County ordered people to stay inside in the cities of South Charleston, Cross Lane, Dunbar and St. Albans, where the Youngs live about four miles from the plant. iReport.com: Where you there? Share your story

Authorities lifted the order about 2:15 a.m. after the Bayer CropScience plant told the county that the explosion did not send contaminants into the air, said Carolyn Charnoch, director of the 911 system in Kanawha County.

The blast sent flames leaping into the night sky, casting an orange glow on industrial towers, but firefighters had extinguished the blaze by about 2 a.m., she said.

A few people complained of a foul odor, she said, but authorities had not heard from anyone complaining of health problems related to air quality, Charnoch said.

Mike Dorsey of the West Virginia Department of Environmental Protection sought to reassure people that the air was safe to breath. The plant contains potentially dangerous chemicals, he said, but the explosion did not release them into the air.

"People should not be concerned about coming outside," he said.

CNN's Greg Morrison, Lateef Mungin and Mark Bixler contributed to this report.

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