Three people exposed to an unknown hazardous chemical brought inside a walk-in clinic north of Covington Wednesday afternoon were decontaminated and treated at a local hospital, a Mandeville district fire chief said.

“They came in contact with the substance but seem to be OK,” Greg Kernan, district chief with Fire Protection District 4, said. “It was more precautionary than anything.”

Donning oxygen masks, green gloves and yellow moon suits, two officials from District 4’s hazmat unit entered United Med Care Walk-In Clinic at 73015 Louisiana Highway 25 about 2:30 p.m. Four hours later, they emerged with the substance later sent to a private company for testing, Kernan said. Analysis should be complete in a week or two, he said.

Capt. Bryan Beaujeaux and officer Zachery Spaph, of Mandeville Fire Protection District 4'€™s hazmat unit, walk toward the door of United Med Care Walk-In Clinic north of Covington to investigate a unidentified chemical brought inside by a patient Wednesday. Three people went to a hospital for minor treatment to the exposed substance.

“We have no idea what it is, but the thing to do is not take any chances,” said Dexter Accardo, St. Tammany Parish’s chief of emergency preparedness. The spill forced authorities to evacuate the clinic and cordon off about a dozen customers and staff, roped off in yellow police tap in the rear of the building.

Some scratched their necks, others wiped sweat from their brow. Many others complained of headaches or skin irritation, Assistant Covington Fire Chief Steve Michell said.

The chemical was brought into the clinic by Mike Valentine, a superintendent of Champion Construction LLC of Covington, who unearthed the substance July 31 at a work site in the 44 block of Tchoupitoulas Street in New Orleans.

Valentine was supervising a crew building a lift station for New Orleans Public Belt Railroad, when, at about 16 feet deep, he struck what appeared to be part of an industrial waste site full of oil filters, oil drums, paint, steal and other debris, he said.

“We were the ones who got to find the goldmine with all the (stuff) down there,” he said.

Railroad officials told him it was diesel, he said.

“It wasn’t,” he said. “It burnt the crap out of me. I’ve been around diesel all my life, and diesel doesn’t do that to you.”

Valentine lifted his jeans. Several horizontal burn marks tapered his legs above the ankle. A pipe layer’s arms were also burnt so bad he had to be rushed to a hospital, Valentine said. Valentine’s wife, Paula, also exposed, vomited. When headaches and skin irritation persisted, the couple went to the clinic for an examination Tuesday.

The doctor on duty told the couple to return the next day with the substance to better determine its origins. On Wednesday, Valentine took in the work boots he wore at the site, now wrapped in a plastic garbage bag for days, and a soil sample in a soda bottle.

“Liquid mushy stuff” fell off his boots and onto the counter, sending fumes wafting through the building that forced people out of the clinic, Valentine said. On Wednesday, the fumes could be smelled outside the clinic. No other businesses, however, were affected.

Railroad officials could not be reached for comment by deadline Thursday.

However, the Louisiana Department of Environmental Quality backed the railroads claims that diesel engine filters made up the majority of the debris found at the construction site, said Rodney Mallett, spokesman for DEQ.

“It’s not unusual to find this kind of material at an old industrial or railroad site,” Mallett said.

An anonymous call Aug. 4 tipped DEQ to the project that also served as an excavation for a water treatment plant for lift station operators, Mallett said.

Railroad authorities will be required to test the hazardous materials under DEQ’s oversight, Mallett said.

On Thursday, it was undetermined if any citations will be issued to the railroad or contractors, he said.

“There was some contamination, but we don’t know the extent right now,” he said.

Chief Engineer Tony Marinello is handling the case for the railroad, but wasn’t available for comment before deadline, a railroad employee said Thursday morning.

The Department of Environmental Quality is investigating the area but did not release any more information before deadline.