(CNN) - A specialty firefighting team from Louisiana has been brought in to battle a fire that has consumed additional tanks at a petrochemical facility in suburban Houston and sent towering black clouds into the air.
The blaze began Sunday afternoon at the Intercontinental Terminals Company, a storage facility in Deer Park. Officials hoped it might be out by Wednesday, but it appears now that the timeline may go longer.
"If it was up to me, we would just end it today and we'd put the fire out. But it's not that simple," Deer Park Mayor Jerry Mouton Jr. told reporters Tuesday. "It's an evolving situation that is very volatile, that changes from one moment to the next."
Seven tanks at the facility are on fire as firefighters fight the blaze with foam and water, ITC officials said. Eight tanks were not burning.
"Our specialty firefighting team from Louisiana has arrived this morning and they are up and running," ITC spokeswoman Alice Richardson said. "We will not hesitate to bring in additional resources as needed."
The fire had intensified overnight because of a temporary dip in water pressure and resources, owners said. But Richardson said officials no longer believe a fire pump failed and are still investigating the cause of the lower water pressure.
There appeared to be some progress.
The battle has now moved from a defensive mode to an offensive one, according to Ray Russell, a spokesman with Channel Industries Mutual Aid, a nonprofit that handles firefighting, rescue and hazardous material in the local refining and petrochemical industry.
He said they believe the fire will not spread from the area that contains 15 tanks.
The tanks on fire contain chemicals that go into making gasoline, including xylene, naptha and pyrolysis gasoline, known as Pygas.
ITC said that air monitoring near the facility has shown readings "well below hazardous levels," and no injuries have been reported. Area schools and businesses reopened Tuesday, even as some health officials worried about the fire's possible effects on air quality in and around Deer Park.
Ryan Sitton, a commissioner with the Railroad Commission of Texas who visited the site, said several teams, including those with the chemical facility and the Environmental Protection Agency, are monitoring the air quality.
"There is a plethora of air quality monitoring that is going on constantly, and it makes me confident that the people of the area are not at elevated risk right now," he said.
The cause of the blaze is under investigation.
A map of the smoke plume footprint from the fire shows a high concentration over Houston and stretching west from the Deer Park facility, according to the National Weather Service.
There's still potential for impacts on health
The Deer Park Independent School District, which reopened schools on Tuesday, said it made the decision to reopen, in part, because air quality monitoring has been "consistently favorable."
Some health officials have expressed ongoing concern about the health impacts of the fire. "I worry when officials say no health effects are expected," Winifred Hamilton, environmental health science director at the Baylor College of Medicine, told CNN affiliate KPRC-TV.
"They're really talking about acute, immediate health effects, and we may still see some of those."
Two neighboring Texas cities said they have canceled outdoor activities where children might be present.
Jacinto City said it has canceled out outdoor activities until further notice, according to city manager Lon D. Squyres.
"We didn't want kids playing on ball fields while this was going on," he told CNN in an interview.
The Galena Park Independent School District in Galena Park canceled all after-school activities, including athletic events.
Some residents told KPRC on Monday they went outside and felt like they were dying, while others said they were getting headaches or that their lungs hurt. A cloud of black smoke continues to emanate from the fire.
Corey Williams, policy and research director for the nonprofit organization Air Alliance Houston, told CNN affiliate KTRK-TV that people could tell "this is not fine" by looking at the smoke cloud.
"The only thing preventing this from being a major catastrophe is favorable weather conditions," he said.
The Deer Park school district is restricting outside activities and calling for home sports events to be moved to other locations or different dates until the fire is over.
The fire began in a single tank on Sunday afternoon and quickly spread to a second tank, ITC said. Authorities reopened Highway 225 early Monday and lifted an order that residents of Deer Park stay inside with their windows closed and central cooling or heating units turned off.
Firefighters hope that once the fire is contained, they can close the tank valves and the fire will put itself out.
Xylene is a solvent that occurs naturally in petroleum, ITC said. Swallowing or breathing the substance can cause death, while nonlethal exposure can cause eye, nose, throat and skin irritation, among other maladies, according to the National Library of Medicine.
Naphtha is a petroleum product resulting from the distillation of natural gas or crude oil, the library says. It can be an eye and nasal irritant.
One tank that caught fire contains toluene, which is used in the production of nail polish remover, glue and paint thinner, ITC said.
Toluene occurs naturally in crude oil and is used as a gasoline additive, "and damage to the central nervous system is the main concern following exposure to toluene in the air," the library says.
According to ITC, the Deer Park terminal opened in 1972 and has capacity for 2.2 million cubic meters -- more than a half billion gallons -- of storage for "all kinds of petrochemical liquids and gases, as well as fuel oil, bunker oil and distillates." The facility has ship and barge docks, rail and truck access and pipeline connections.
Richardson became emotional earlier Tuesday when a reporter asked if the company wanted to apologize to the residents of Deer Park.
"This isn't an event we wanted or planned," she said.
She said about 30% of ITC's employees live Deer Park and the neighboring city of La Porte, and they are concerned.
"Of course, ITC would apologize to any of them," Richardson said.
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