Growth and development on the city’s South Side could have exacerbated an oil spill last week that made its way onto the property of Mission San Juan and into the San Antonio River, a San Antonio River Authority environmental investigator said Wednesday.
National Park Service officials and Texas environmental regulators are actively investigating the oil spill, which took place April 21. The spill from the San Antonio Refinery was the result of heavy rains last week and a power outage, which together caused oily water from the water treatment plant at the refinery to spill over, The San Antonio Refinery said in a statement. The refinery is owned by Allegiance Refining LLC.
While a statement from the refinery said “there was no impact to the community from this incident,” an environmental investigations specialist for the San Antonio River Authority said officials estimated that between 9 and 12 gallons of oily water spilled into the mission’s historical acequia, which reached the river.
Cleanup efforts were complete as of Wednesday, said Ronnie Hernandez, an environmental investigations specialist for the river authority.
“There’s been a lot of development in the Brooks area,” Hernandez said. “A lot of impervious cover [is being built over there]. They’re going to start experiencing a lot of rain flow over there because of that, and I think [the refinery was] just overwhelmed and surprised that much water came into their facility.”
In a followup statement sent to the San Antonio Report, refinery spokeswoman Angie Dasbach said officials “plan on contacting the appropriate parties at the City of San Antonio to discuss stormwater management to see if there are improvements that can be made.”
The San Antonio Refinery is an independent refiner processing crude oil and condensate with a permitted capacity of 21,000 barrels per day, according to the website for Allegiance Refining, which has owned the facility since December 2020. It’s located near both Mission San Juan, one of the Spanish colonial missions designated a UNESCO World Heritage site, and Brooks, the former military base that is being redeveloped with new housing, manufacturing plants, lodging and retail.
While Hernandez said the spill was “relatively small,” he added that larger amounts of oil can harm wildlife.
“A little bit of oil goes a long way when it hits water,” Hernandez said. “We’ve seen waterfowl die having come in contact with jet fuel and oil in the river. We normally don’t get fish kills; there’s so much water volume in the river — but if it were a small creek with a very healthy fish community, then you might see a much bigger impact to the aquatic community.”
In this instance, wildlife doesn’t appear to have been negatively affected by the oil spill, he said, but federal parks officials, environmental regulators and refinery officials plan to monitor the area and possibly test soil samples to be sure, Hernandez said.
Parks officials became aware of the incident shortly after it occurred, the National Park Service said in a statement.
San Antonio Missions National Historical Park is working to assess and mitigate damage and conduct all required documentation investigations, NPS said.
The refinery took swift action to ensure the oil was cleaned up, Hernandez said, adding he was impressed by the lengths to which refinery workers went to assure minimal impacts.
“This is the first incident that we’ve seen in four to five years; the previous owners did a lot of retrofitting of containment systems,” he said. “The refinery did a massive, very aggressive response on their end.”
The response included calling in contractors to lay down booms and absorbent pads along the impacted area as soon as possible, Hernandez said. The San Antonio River Authority acted as a secondary containment effort.
