CORPUS CHRISTI, Texas – UPDATE (10:30 p.m.): Corpus Christi city officials on Thursday night said the problem with the drinking water was corrected in Zone 1, which includes Flour Bluff, Padre Island and Calallen.
People in Zone 1 can use the tap water for consumption, bathing, washing hands, dishes and clothes, brushing teeth and bathing.
Officials said the rest of the city continues to be under current restrictions.
For more information, click here to see the map of affected areas.
ORIGINAL STORY: More than 300,000 people in Corpus Christi are still awaiting word that the water is safe to drink.
At a new conference, the mayor said there was no update, but testing could return as early as 8 p.m.
Corpus Christi warned its residents not to use tap water after a chemical contaminated the water supply.
Corpus Christi officials said in a statement that a "back-flow incident" in an industrial area Wednesday may have led the chemical to seep into the water.
Thursday morning, the chemical was identified as Indulin AA-86, an asphalt emulsifying agent. City officials said that between three to 24 gallons of the chemical got into the water supply from an unnamed facility in that industrial district.
District 1 City Councilwoman Carolyn Vaughn said the company that Valero blamed for the incident was Ergon Asphalt.
Vaughn said residents are very frustrated over the situation.
"We've had some water boils in the past. For this to happen, and even if it wasn't our city employees who did it, we're still responsible for the water supply of this city to be safe," she said. "We're frustrated but we're trying to get all the answers we can rectify the situation."
Valero Refining blamed "third party operations" for the water situation in Corpus Christi.
"At this time, we believe this is a localized backflow issue from third party operations in the area of Valero’s asphalt terminal," Valero spokeswoman Lillian Riojas said in a statement. "We do not believe this issue is being caused by Valero’s Corpus Christi refineries. While the City continues to investigate this issue, we do not believe the City’s water has been impacted," the statement reads. "We believe this issue is isolated to a lateral industrial line. Valero is offering its resources to assist the City in isolating the issue and to help confirm this has not impacted the City’s water supply."
The warning prompted schools to close and a rush on water at grocery stores, where long lines formed with people pushing carts filled with packages of bottled water.
"H-E-B's top priority is making sure our stores are fully functional and supply is strong to support the needs of our customers," H-E-B spokeswoman Julie Bedingfield told KSAT 12 News. "We sent water overnight and will continue to do so as needed. Customers in Corpus may purchase up to three cases of bottled water or gallon water per customer."
Walmart spokeswoman Leslee Wright said the retailer is also working to provide ample supply of bottled water in stores.
"We're working with our suppliers and our network of stores and clubs to accelerate water deliveries and supplies," Wright said. "These deliveries will begin to hit shelves (Thursday) afternoon. We're engaged with state and local officials to assess where we can be of best help to the community."
Womack said 100,000 cases of bottled water was on its way to Corpus Christi.
"Donations are coming in left and right," Womack said.
Corpus Christi Independent School District spokeswoman Leanne Winkler Libby said the district is closely monitoring the situation.
Classes have been canceled for Friday.
Timeline of water problems in Corpus Christi: