COLUMBIA -- An executive of Diamond Pet Foods, which announced a recall of two varieties of cat food, said Thursday that the tainted products were manufactured at the same Gaston plant that in 2005 produced a toxic dog food responsible for the deaths or illnesses of dozens of dogs around the nation.

"Yeah, it's out of Gaston," Diamond president Mike Kampeter said. Kampeter declined to answer further questions about the plant, which employs about 100 people.

The federal Food and Drug Administration, which has oversight of pet-food manufacturing, said an investigation is under way.

The probe could lead to enforcement actions aimed at getting the company to correct problems, a spokesman said. In July, Diamond announced a $3.8 million expansion of its Lexington County plant that would add 37 employees to its work force.

On Sept. 23, Diamond voluntarily recalled Premium Edge Finicky Adult Cat Food and Premium Edge Hairball Cat Food. The Meta, Mo.-based company said the recall was necessary because the products had "the potential to produce thiamin deficiency."

The FDA said there were reports of 21 cases of thiamine deficiency, which can cause neurological problems and loss of appetite in cats, but no deaths. Cases were confined to New York and Pennsylvania, and none has been reported since Oct. 19.

Bags of the tainted food were distributed at stores in 18 states, including South Carolina.

Four years ago, Diamond's Gaston plant was the source of dog food with a poisonous fungus called aflatoxin in it. The fungus came from the corn used in the food production.

The FDA reported 76 dogs had died after eating the food and an additional 21 became ill.

The latest recall includes food that was manufactured in Lexington County from May 28 to Aug. 30, the company said.

Kampeter said the company issued a voluntary recall Sept. 23, asking retailers to pull the two cat food products.

A spot check of some of the two dozen retail outlets in Lexington and Richland counties found the stores had been notified earlier and removed the product.

Diamond said it tested the product and determined there were no contaminants in the cat food. It also tracked the vitamin premix lot number and notified distributors and retailers.

Further testing on another lot of the Premium Edge brand was done and there was no thiamine deficiency, the company said.