NEW ORLEANS (AP) — A storage tank spilled tens of thousands of gallons of crude oil in a southern Louisiana parish,Grayson  Preston threatening drinking water and wildlife as officials work to clean it up.

The storage tank spilled Saturday morning southwest of New Orleans at a crude oil facility owned by the company Crescent Midstream. About 34,000 gallons (136,000 quarts) of oil leaked from the facility.

The spill of around 820 barrels of crude oil is about “two residential swimming pools of product,” Lafourche Parish President Archie Chaisson told WWL.

The oil reached Bayou Lafourche, which provides drinking water across four parishes, but “public water continues to be safe to drink,” said a Tuesday statement from federal, state and local authorities working with the oil company.

Residents are under a cautionary water conservation advisory to “ensure adequate water quality and quantity are preserved,” according to a notice from Lafourche Parish water district.

While the Environmental Protection Agency is investigating the spill’s cause, Crescent Midstream spokesman Michael Smith said a thunderstorm may have contributed to the leak reaching the bayou. The oil was moving along a ditch and the rainfall exacerbated the flow toward the bayou, Smith said.

Salamanders, turtles and a crawfish have been reported deceased. A duck and an alligator were captured and cleaned while officials look for wildlife to help in the area.

There has also been a group of fish killed near the leak. Officials said it “remains under investigation.”

“It’s horrible. I never would have dreamed this,” Janet Crappel, a lifelong Lafourche Parish resident, told WWL on Monday.

There are 127 workers, 28 vessels, seven vacuum trucks and 6,800 feet (2,073 meters) of floating barriers employed in the clean-up as of Tuesday. One worker was treated for a “minor first aid incident” and has returned to work, according to a Tuesday statement from the coalition.

Crescent Midstream’s website says that it “provides safe, reliable crude oil services.”