Washington (CNN) -- A beef recall is under way in a half-dozen states involving possibly contaminated products from the Oklahoma company National Steak and Poultry, according to the firm and federal inspectors.

U.S. Agriculture Department officials said a cluster of illnesses involving the E. coli bacteria was reported in Colorado, Iowa, Kansas, Michigan, South Dakota and Washington state.

The cases then were linked with beef the Owasso, Oklahoma, company produced in October, prompting the government to direct a Class I recall, indicating the highest risk of illness if the products are consumed.

On Thursday, National Steak and Poultry began a voluntary recall of 248,000 pounds of beef products marketed under its name as well as under names that include Carino's Boneless Beef and Moe's Beef Steak.

A consumer hotline at the company carries a recorded message noting "this is the first recall in our company's nearly 30-year history."

National Steak and Poultry did not acknowledge any contamination in its beef processing or packaging facilities, but the recording said the firm "will err on the side of being cautious" with the recall.