When flames broke out at a Deer Park chemical storage terminal last spring, sending a plume of smoke into the air that was visible for miles, firefighters spent days spraying foam over the smoldering tanks to put out the blaze. Then a dike wall failed, releasing tens of thousands of gallons of water mixed with foam into the Houston Ship Channel.

Now researchers are focusing on the lingering presence of these “forever chemicals” in local waterways and their potential health effects.

Months after the incident, researchers still found traces of the perfluoroalkyl and polyfluoroalkyl substances, known as PFAs, in the area, although little is known about their long-term impacts on humans and aquatic life.

“Unlike air pollution, where after the fire is out and the smoke is gone air pollution levels return back to normal (within a week or two) after the incident, in this case it took a month or two for the ship channel and surrounding waterways to really go back to ‘normal’ levels of these compounds,” said Weihsueh Chiu, professor at Texas A&M.

Researchers presented their findings and talked about the environmental impacts of the ITC fire Monday in Seabrook.

The Galveston Bay Foundation and Texas A&M Superfund Research Center have spent the last several months collecting and analyzing water samples along the ship channel and beyond to determine potential water quality impacts of the March 17 Intercontinental Terminals Co. fire, where a tank holding the toxic chemical naphtha caught fire about 20 miles southeast of downtown. By the time the blaze was extinguished, 11 of the 15 tanks, with a capacity to hold up to 80,000 barrels each, had burned for 64 hours. While no injuries were reported, there were several calls for residents to shelter in place.

Then on March 22, the containment wall breach sent an unknown amount of chemicals mixed with water and fire-suppressing foam into the ship channel, the busy waterway used by ships to go between Houston-area terminals and the Gulf of Mexico. By the end of April, more than 9.4 million gallons of oily water had been recovered from nearby waterways. Another 11.7 million gallons of product mixed with water and firefighting foam had been collected from the tank farm, government and company officials reported.

Even before the breach, the Galveston Bay Foundation was concerned about PFAs given the size of the fire and the amount of firefighting foam being used to put it out, said Bob Stokes, director of the foundation.

These chemicals have been in use since the 1940s and can be found in many products including food wrappers, fabrics and firefighting foam. Some of the PFA compounds have been linked to illnesses, including cancer, although the extent of their harmful effects remains widely unknown. They are water soluble, are persistent in the environment and accumulate in both the water column and wildlife.

“The short-term exposure pathways were likely very limited — no one is drinking the water out of the Houston Ship Channel, no one is likely swimming in the Houston Ship Channel,” Stokes said.

But researchers don’t know what it could mean to fish or shellfish or to people fishing in the area months later.

“The area where the fire was is tidal, so the tides flow upstream and downstream a couple of times a day. So basically this stuff just sloshed around for a while before it could flush into the system into Galveston Bay proper and ultimately … be flushed down into the Gulf of Mexico as well,” Stokes said.

A concern, he said, is that “this stuff doesn’t really degrade.”

“So even though it’s not in the upper ship channel anymore and it is not likely in Galveston Bay, it’s somewhere and that’s probably in the Gulf of Mexico at much, much lower levels,” he said. “But it hasn’t disappeared because this stuff stays around forever.”

From the beginning of the environmental disaster through August, researchers took more than 50 samples from nearly a dozen locations around ITC, as far away as Morgan’s Point to the southeast and Santa Anna Marker to the west.

They wanted to complement the work of the Environmental Protection Agency and the Texas Commission on Environmental Quality, Chiu said, as well as track trends.

The group found high concentrations of some of the compounds in the early days and weeks after the fire, especially in areas closest to the ITC complex.

By April, “it seems it was starting to flow away from the initial sources,” Chiu said, and from June through August, the levels remained “quite low.”

The challenges with interpreting the data, Chiu said, is that most of the regulatory standards are based on drinking water because that has always been the main concern. But these standards didn’t apply to the ship channel.

Instead, the researchers modified those standards for one of the compounds for which data was available and calculated the risk of swallowing water by accident when swimming, for instance.

“For that specific use of swimming and accidental ingestion and for only that specific compound, we determined it wouldn’t be a public health concern for that specific scenario,” Chiu said.

He added, “That being said, there’s a lot that is unknown in terms of environmental impacts … and for the vast majority of these compounds, there aren’t any regulatory limits at all and very little data on toxicity to use as a benchmark to compare whether or not levels we found are or are not of concern.”

The next steps include further analyzing samples taken in the aftermath of the fire for additional PFAs, as well as developing maps that can be published online with their results, Chui said.

The Centers for Disease Control and Prevention agreed that the human health effects of exposure to low levels of PFAS are “uncertain,” though some studies have showed negative effects on lab animals given large amounts of certain types.

While this research is only a first step, Stokes said, “it has done a really good job documenting the presence of PFAs that we feel like is conclusively tied to the impacts from the ITC fire. What it doesn’t do, and what we think there needs to be more research on, is what it really means, what health impacts might be caused because of this.”

It’s been only more recently that the federal government and research community have started to focus on this group of chemicals, but there are thousands, with the vast majority lacking data, researchers said.

This case study, though, has prepared them for future incidents, they said, and could be a starting point to have conversations about this group of chemicals in Texas.

“There are several states looking at PFAs potentially for water quality standards, and Texas is not at this point. From a public policy standpoint, should Texas be doing more on this?” Stokes said. “I don’t have the answer, but I think we have to have these conversations and figure out if this should be a priority for the state of Texas.”

perla.trevizo@chron.com