New data show hazardous chemical substances stayed in the Houston Ship Channel for months after a fire broke out in March at the Intercontinental Terminals Company (ITC) petrochemical facility in Deer Park. The fire burned for days, sending a black plume of smoke over the area, and runoff from putting out the fire leaked into the ship channel, which flows into Galveston Bay.
In the aftermath of the fire, researchers from Texas A&M University and the Galveston Bay Foundation teamed up to conduct additional water testing, looking for the presence of per– and polyfluoroalkyl substances, or PFAS. PFAS are a group of man-made chemicals that have been linked to adverse health effects such as cancer and thyroid problems. They can be found in industrial items like nonstick cookware, as well as in firefighting foams, like the kind used to put out the ITC fire.
“These are often called forever chemicals because they are very resistant to breaking down in the environment,” said Weihsueh Chiu, a professor at Texas A&M University. “Many chemicals that are released in the environment eventually break down into other compounds that are not harmful, but in this case, these chemicals tend to be very persistent.”
During the ITC fire, more than 130,000 gallons of foam were used to put out the blaze. At one point, one of the containment walls surrounding the tank farm collapsed, sending water mixed with firefighting foam into the ship channel.
Nick Ellis, the Water Quality Programs Coordinator at the Galveston Bay Foundation, said they had started testing the water a few days after the fire started. “The containment berm collapsed while we were right there at Tucker Bayou, and that’s when all the firefighting foam started getting out there,” he said. “And then that’s when PFAS came onto our radar. That’s when it started really picking up steam.”
The EPA tested for PFAS immediately after the ITC incident, but because there hadn’t been monitoring prior to the fire there was no baseline data for comparison, according to the researchers.
“We wouldn’t be able to really distinguish as to whether what we were finding was actually caused by the foams that were being used running off into the ship channel, or whether there was a high background already from other sources,” said Chiu. “That’s why we continued to do sampling in April all the way through to August to see are the levels going down to some baseline level or are they just always elevated?”
The researchers took nearly 60 samples from March through August, in both the area right next to ITC and farther down the channel.
In the sites closest to ITC, the researchers found that PFAS levels peaked soon after the incident, while farther away from the site the levels peaked in April. Levels stayed elevated until about mid-June, after which they underwent a steep decline and stayed low through August.
“Just because the source of these contaminants is stopped, there isn’t an immediate reduction in the concentration. In this type of watershed it takes some time for the concentration to clear out and dilute, essentially, into the larger Galveston Bay,” said Chiu.
What are safe levels?
The levels of PFAS detected in the water were above regulatory limits for drinking water, but as the researchers pointed out nobody is drinking from the Houston Ship Channel.
“The levels that we found were certainly above drinking water levels, but this isn’t going to be used for directly drinking that water,” Chiu said.
He said they did an additional calculation for recreational use for one of the compounds, taking into account accidental ingestion while swimming.
“All the samples that we took would be below those recreational equivalent levels, so it would be safe for people under this lamp post of looking at this one particular perfluorinated compound and that recreational scenario,” Chiu said.
But the researchers said more study on the impacts of PFAS is needed to fully understand the health and ecological impacts.
“We’re essentially documenting the presence of the PFAS, but our research stops there,” said Bob Stokes, President of the Galveston Bay Foundation. “We’re not in a position to say what it means from a health standpoint, from a marine safety standpoint, there’s still more work to be done there.”