About 700 people sought treatment for nausea, headaches and other symptoms in the chemical disaster zone east of Houston, with 15 of the most severe cases loaded onto ambulances and hauled to hospital emergency rooms.

The wave of sickness sweeping the industrial suburb of Deer Park and neighboring communities near Intercontinental Terminals Co.’s chemical storage complex was evident at an ad-hoc clinic set up after the March 17 fire and subsequent benzene releases. The 15 hospitalized patients were suffering serious respiratory difficulties, said Umair Shah, executive director of Harris County Public Health.

That tally only included people who sought help at the clinic in Deer Park, which is about 20 miles east of downtown Houston. No firm numbers were available from local authorities on how many more across the metropolitan area took themselves to hospitals or were rescued at home by paramedics.

On Friday afternoon, the disaster site temporarily reignited, with multiple sections of the complex belching smoke and flames, and sending a new black plume over the fourth-largest U.S. city.

Mercy Reyna, 50, and her 18-year-old daughter Rebecca were suffering from headaches, eye discomfort and chest tightness, and had been waiting for 2 1/2 hours at the pop-up medical center when the new fire erupted. They left without being seen because they didn’t want to get marooned there if the city ordered everyone to stay indoors.

“I was filling out the paperwork inside, and my eyes were running and running with tears,” Mercy Reyna said. “It was just that desperation of wanting to get your eyes out and just rub them and rinse them and put them back. It’s just that burning sensation.”

The latest blaze erupted just hours after a wall holding back almost a million gallons of toxic, flammable liquids collapsed, and just two days after the original conflagration was suppressed. Intercontinental, a unit of Japan’s Mitsui & Co., said three tanks and a drainage ditch were alight before firefighters suppressed the flames after more than an hour.

AG FILES LAWSUIT

One of the tanks involved in the new blaze contained xylene, a toxic byproduct of the oil-refining process, while the other two held gasoline components.

The breach in the containment wall had been plugged as of Saturday morning but efforts to drain toxic fluids still held in one of the damaged tanks are on hold until the wall can be fortified, according to ITC.

Although the company said Friday that there were about 2.52 million gallons of hazardous chemicals still held in the damaged section of its complex, by Saturday morning it no longer knew how much remained. Meanwhile, Texas Attorney General Ken Paxton filed a lawsuit accusing ITC of violating clean-air laws.

“There’s more tanks in there. Is it going to reignite? It’s very uncertain,” Reyna said. “The trust is not there. We feel like we’re not being told the truth of what’s going on.”

People at nearby industrial sites and a state war memorial had already been warned to take cover when the key containment wall failed, prompting the Coast Guard to shut part of the Houston Ship Channel, which abuts ITC’s complex. The channel is one of the busiest commercial shipping facilities in North America, connecting Houston’s manufacturing and oil-refining nexus to Galveston Bay and the Gulf of Mexico. It remained closed Saturday.

Although the ship channel is a key maritime thoroughfare, it’s not a source of drinking water for Houston or its suburbs. After the wall failed, officials issued take-shelter warnings to neighboring companies and visitors to the San Jacinto battlefield, site of the 1836 fight that won Texas independence from Mexico.

The U.S. Environmental Protection Agency has been testing water samples from the so-called containment area surrounding the tanks that burned.

The U.S. Chemical Safety Board announced late Thursday it will investigate the blaze. The Texas National Guard dispatched troops to assist local authorities with air monitoring after cancer-causing benzene wafted across the area.