Staff on Friday was still working on the problem that caused water to end up in the regular gas tanks and pumps at the duty free gas bar on the U.S. side of the Ambassador Bridge.

A stop work order, issued by the Michigan Department of Agriculture and Rural Development, remained in effect Friday afternoon and premium gas is still being sold there at regular price, until the problem is fixed.

Water in gas sold at the Duty Free plaza on the American side of the Ambassador Bridge is being blamed for four cars breaking down on their way to Canada, CBC News has learned.

Phil McKay said his mechanic told him there was water in the gas tank of his Hyundai. It broke down just after he filled up at the Duty Free gas bar Wednesday evening.

Jennifer Holton, from the Michigan Department of Agriculture and Rural Development, told CBC News it appears there was water in the pump's gas line. 

"We identified water in the gasoline [taken from the gas station]," Holton said. "It's still in process, the [bridge company] is currently pumping water out of their underground storage tank. There was approximately 135 gallons (511 litres) of water in their underground storage tank."

The department of agriculture is responsible for monitoring gas pumps in the state.

Holton said the bridge company is co-operating, through a stop sale order has been issued until all the problems are resolved. She said she is unsure of how water got into the tank, or how it ended up in the vehicles.

"They're doing everything they should be to get back in business," Holton said.  

Four cars had to be towed off the Ambassador Bridge Wednesday when they broke down heading into Canada.

Stan Korosec, the director of security and Canadian government relations for the bridge company, said all four drivers had reported filling up with regular gas at the Duty Free gas bar.     

The bridge company then closed the regular gas pumps and began selling premium gas at regular prices.

"Apparently, it was some sort of technical issue with the way the pumps were functioning," Korosec said. "During that brief time, we had about 750 fill-ups that day but it seems these four particular customers were affected by whatever this technical glitch was."

According to Korosec, it is common for some water to sit at the bottom of a gas tank. The shut-off system that normally keeps water out of the pump appears to have stopped functioning, he said.

Korosec said the gas pumps were expected to be working Thursday evening but said Friday staff was still working on the problem and premium gas was still being sold at regular price.

He promised to reimburse the affected motorists for the "technical glitch" that caused the issue.  

Customers who bought fuel at the gas bar Wednesday and are having problems with their vehicle are encouraged to call the Ambassador Bridge to provide details of what happened, Korosec said.  

That number is 313-989-0136.