Cleanup from a South Side refinery’s chemical spill into the San Antonio River is complete after authorities managed to contain and soak up the chemical, according to people involved in the spill response efforts.
On Thursday morning, approximately 50 gallons of naphtha reached the San Antonio River after leaking from a valve at the Calumet Specialty Products refinery at 7811 S. Presa St., according to a notice from the City’s Office of Emergency Management shared on Twitter by City Councilwoman Rebecca Viagran (D3).
The spill left a chemical sheen on the water’s surface and smelled like “really strong gasoline,” said Amanda Nasto, an environmental investigations specialist with the San Antonio River Authority who was involved in the cleanup.
“As soon as Calumet saw there was a sheen in the water, they contacted us because we do have spill containment kits at our facility,” Nasto said. “We were able to respond immediately.”
Naphtha is among the chemical and fuel products produced by Calumet’s San Antonio refinery, according to the company’s website. Media Oakes, Calumet communications manager, described it in an email as a “liquid hydrocarbon mixture used in fuels and solvents.”
Nasto said River Authority, Calumet, and San Antonio Fire Department crews laid a plastic boom across the river to help “corral” the naphtha. They also used adsorbent fiber booms and pads that could help pick up the chemical and remove it from the water.
“This product is lighter than water, as it sits at the surface,” Nasto said. “We put that on the surface and it just skims it off.”
Oakes said the crews left the booms in place across the river overnight Thursday “as a precautionary measure.”
“Calumet is investigating the cause of the incident,” Oakes said, adding that the company “remains committed to operations that prioritize health, safety, and environmental stewardship.”
Around 1 p.m. Friday, around 20 to 25 Calumet emergency response personnel were removing the boom. Nasto said cleanup efforts were finished by early Friday afternoon. One boom placed around a culvert leading from the refinery’s property is set to remain in place until Saturday, she said.
Investigators with the Texas Commission on Environmental Quality also responded to the spill. The TCEQ is still investigating the incident and will have a report available when complete, spokesperson Andrea Morrow said in an email.
Nasto said she did not observe any negative effects of Thursday’s spill on fish or wildlife in the river. Because the chemical cannot mix with water, she did not expect any ecological affects below the water’s surface.
“I spent the past two days walking up and down the river,” she said. “We didn’t find anything being impacted.”

The refinery has had other spills prior to Thursday’s, including a 2014 spill when hundreds of gallons of jet fuel reached the river. Nasto said Calumet staff train with River Authority and fire department crews to be prepared to respond to these incidents.
“We’ve had spills in the past, and it’s been way worse,” she said. “Because we’ve been training for this, we were able to respond quickly.”
