Gov. John Carney has authorized the National Guard to assist residents of a southern Delaware town after high levels of toxic chemicals were discovered in municipal wells.

Authorities said Friday that the Guard has provided two 400-gallon portable water tanks and coordinated troops to ensure 24-hour water distribution operations to the residents of Blades. A 5,000-gallon water tanker is prepared for follow-up support, officials said.

State environmental and public health officials announced late Thursday that sampling requested by the Environmental Protection Agency found concentrations of perfluorinated compounds above the human health advisory level of 70 parts per trillion in all three of the town's drinking water wells.

Timothy Ratsep, a program administrator for the Department of Natural Resources and Environmental Control, said results from sampling done in late January showed PFC levels in the three wells ranging from 96 to 187.1 parts per trillion.

"We do not know the source or sources here, and we're continuing to evaluate the conditions," he said.

Water will be supplied to the town, which has a population of about 1,400, "out of an abundance of caution" until the extent of the contamination is determined, officials said.

State officials called the well water safe for bathing and laundry, but not for drinking or cooking.

Although PFCs are not regulated by the Safe Drinking Water Act, the EPA has said exposure to perfluorooctanoic acid, or PFOA, and perfluorooctane sulfonate, PFOS, over certain levels can have adverse health effects. Studies have shown those effects to include developmental effects to fetuses during pregnancy or to breastfed infants, cancer, liver damage, changes to the immune system and thyroid, and cholesterol changes, according to the EPA.

Members of Delaware's congressional delegation released a statement saying they are "extremely troubled" by the situation. Vikki Prettyman, town administrator for Blades, did not immediately return telephone messages Friday.

In an annual drinking water report released last year, the town said its water, drawn from a shallow aquifer, has a high susceptibility to petroleum hydrocarbons, pesticides, other organic compounds, metals and other inorganic compounds, and a moderate susceptibility to nutrients, pathogens, and PCBs.

Ratsep said Blades was selected for sampling a few months ago as part a statewide effort to identify areas where there may have been releases of perfluorinated compounds. Such chemicals are used in a broad range of industrial applications and consumer products, including textiles, food packaging, firefighting foams and metal plating.

Blades has been home to two metal plating businesses, one of which is still in operation.

"That's why Blades was selected using EPA funds to sample for these compounds," Ratsep said.

One of the companies, Peninsula Plating, abandoned operations in the 1990s. The other, Procino Plating, currently fabricates griddle tops and associated hard chrome plating, according to a 2016 consultant's report.

Procino Plating has been the subject of ongoing efforts to remediate groundwater contamination from chromium. The company has been cited several times for violations related to hazardous waste management and was the subject of a federal criminal investigation in 2010. The company's owner at the time was sentenced to a year of probation in 2014 and ordered to pay a $50,000 fine after pleading guilty to one count of illegal storage of hazardous waste without a permit. The company itself was sentenced to five years' probation for violating the Clean Water Act.