Published Sunday, Dec. 18, 2016 | 11:44 a.m.
Updated Sunday, Dec. 18, 2016 | 1 p.m.
A nearly four-day ban on drinking the water in Corpus Christi, Texas, was lifted on Sunday after test results showed no contamination due to a chemical leak, the city's mayor announced.
Mayor Dan McQueen said residents could resume using the city's water supply for drinking, bathing and cooking.
"It is all full use but we are going to continue to monitor as we go on," McQueen said.
None of the 28 drinking water samples the Environmental Protection Agency reviewed tested positive for Indulin AA-86, an asphalt-emulsifying agent that's corrosive, the federal agency said Sunday in a statement. Indulin can burn the eyes, skin and respiratory tract if a person comes into contact with concentrated amounts.
The water ban had been issued late Wednesday out of concern that a chemical leak at an asphalt plant leased to Ergon Asphalt and Emulsions by oil refiner Valero could have contaminated the city's water supply.
The EPA said there have been seven "unconfirmed" reports of symptoms possibly related to prohibited water use. The federal agency, along with the Texas Commission on Environmental Quality, will continue collecting and testing water samples over the next few days.
McQueen said officials will continue investigating the leak at the asphalt plant and seek possible damages from those responsible.
EPA spokesman David Gray said Saturday night the federal agency would begin an in-depth investigation of the leak "and take appropriate action" as soon as it finished with the water testing.
On Saturday, city officials had said that there had been three reports of dirty water before the ban had been issued.
There has been some confusion over when city officials were notified of the serious water problems at the plant site that ultimately led to the water ban.
There had been two reports earlier this month of dirty water at the plant site that resulted in city workers flushing out pipes. City officials have said such dirty-water reports are common.
Valero said in a statement Saturday that it then notified the city of "milky, sudsy water" at the plant on Dec. 7, a week before the water use ban was announced. Ergon had said in a statement that it uses a soap solution comprised of about 98 percent water and 2 percent Indulin and hydrochloric acid in its asphalt operations.
Assistant City Manager Mark Van Vleck had told The Associated Press on Saturday that city technicians responding to dirty water complaints at the plant were not alerted to white, sudsy water until Dec. 12.
But on Sunday, Van Vleck said he believes Valero's version of events is probably accurate.
"When I read it I said, 'That's a little different from what I've been told,'" said Van Vleck, who added that he was going on what people in the public works department had told him.
Ergon has acknowledged the "soap solution" had backflowed into a pipe through which it receives water at the plant. It said that pipe isn't directly connected to the city water main but rather is interconnected.
On Sunday, Ergon said it was pleased the water ban had been lifted and would continue to cooperate with officials.
Officials in Corpus Christi began on Sunday to dismantle distribution centers that had been set up to give water to residents, said City Manager Margie Rose.
The mayor cautioned residents to be conservative in their water use to avoid overtaxing the system after water tanks were flushed in parts of the city, which has about 300,000 residents and is located along the Texas Gulf Coast.
"This certainly isn't something the city wanted to do," he said. "My heart goes out to everybody in our city right now. And I apologize. I apologize personally."
This was the latest in a string of water scares for the city. In May, the city issued its third boil-water advisory in a year as a precaution after nitrogen-rich runoff from rain flowed into the water system, resulting in low chlorine disinfectant levels in the water supply.
Associated Press writer Frank Bajak in Houston contributed to this report.