BATON ROUGE — Some motorists who took advantage of Circle K's 40-cents-off promotion last month received an unwanted extra: Water in their gas tank.

The company acknowledged Monday that it was responsible for accidentally delivering watered-down gasoline on the day it ran a major promotion ahead of the Memorial Day holiday. Many drivers had gone on social media to complain about what happened to their vehicles.

"The car troubles experienced by some customers who purchased fuel at our store on Highland Road at Lee Drive on May 23 resulted from water that seeped into an underground storage tank following recent heavy rains in the Baton Rouge area," the company said in a statement.

"At Circle K, we guarantee and stand by the quality of our fuels. However, issues sometimes do arise, and we ask for customers to report them to us as soon as possible so that our claims team can review them," it said.

Stacie Nola said her 2-year-old car started acting up the day after she refueled.

"My car started hesitating and then on Saturday morning the 'Check Engine' light came on," Nola said. Her mechanic diagnosed bad gas. It cost around $400 to address the problem, she said.

The Louisiana Department of Agriculture and Forestry, whose standards division regulates gas pumps, did not immediately have a tally on how many people had filed complaints with the agency. Circle K, meanwhile, said it wanted to hear from customers impacted at (800) 308-2570.