Editor's note: This story has been updated with a comment from state Rep. Briscoe Cain, R-Deer Park.
Tens of thousands of people east of Houston were told to stay indoors for hours Thursday after benzene and other volatile organic compounds were found in the air within the city limits of Deer Park.
The order came one day after a fire that broke out at a petrochemical storage facility there was extinguished. Residents in Deer Park and neighboring Galena Park were told to close their windows, turn off their air conditioning and stay off certain roads. But by noon, the shelter-in-place order had been lifted for Deer Park after air quality monitors reported "sustained period of improved readings." It remained in place for Galena Park.
The Texas Commission on Environmental Quality, the state's environmental regulatory agency, said in a news release Thursday morning that some areas of the city had benzene concentrations high enough to cause health concerns. TCEQ said that at the maximum levels detected, the benzene levels could cause headaches and nausea, but no long-term effects.
“Because the fires are no longer burning, vapor from remaining exposed chemicals can escape. The remaining product is being removed, and vapor suppression activities are continuing,” the release said.
State Rep. Briscoe Cain, R-Deer Park, called for a joint hearing with the House Committees on Homeland Security and Public Safety and Environmental Regulation to evaluate the city’s response to the incident and investigate the fire’s effects.
“The nation has been captivated by dramatic images of flames and smoke plumes, but our community has had to deal with the very real questions about air and water quality while waiting for information from ITC,” Cain said in a press release. “Our community deserves transparency and accountability as we recover from this incident.”
The federal Chemical Safety Board, an independent agency that investigates serious chemical accidents, also announced Thursday that it was opening an inquiry into the spill.
"CSB investigators will start interviews next week and plan to be on site for several days to document the scene and collect evidence," the board said in a statement.
The city issued the shelter-in-place warning early Thursday morning, and officials advised residents to close any sources of outdoor air, according to a city emergency alert. The warning also advised residents to turn off air conditioning and heating systems and close fireplaces to keep chemicals from entering homes.
Deer Park has a population of over 33,000, according to the U.S. Census Bureau. Galena Park has a population over over 11,000.
Some school districts in the area cancelled school Thursday, including Galena Park Independent School District, according to a city emergency alert. Deer Park and two other school districts canceled Friday classes, the Houston Chronicle reported late Thursday.
On Sunday morning, a fire broke out at a facility owned by Intercontinental Terminals Company. The fire spread through tanks that contained chemicals used in gasoline, and blazed for three days before being extinguished. The blaze caused a tall black plume to hang over Houston, the nation's fourth-largest city, for days. But government officials insisted during the fire that the air remained safe to breathe.
No shelter order had been issued in Houston Thursday morning, and Houston ISD schools remained open. School officials emphasized that no benzene had been detected outside the shelter-in-place zone, though the district hired contractors to test air conditions at schools on the east side of the city "out of an abundance of caution."
TCEQ said its staff would be extensively monitoring the air quality, and asked for additional air monitoring equipment from the Environmental Protection Agency, which will arrive and begin operations Thursday, according to the release.
The ITC facility where the fire occurred has been open since 1972. The TCEQ fined the company at least 10 times since 2002 for various pollution incidents.