WASHINGTON (AP) – None of the contaminated wheat gluten that led to the American recall of pet food went to manufacturers of food for humans, the ingredient’s importer said Tuesday.

The Chinese wheat gluten imported by ChemNutra Inc. all went to companies that make pet foods, Stephen Miller, chief executive officer of the Las Vegas company, told The Associated Press.

Mr. Miller declined to identify what companies ChemNutra supplied. Nearly 100 brands of cat and dog foods made with the ingredient, since found to be chemically contaminated, have been recalled.

The recalled pet food apparently has resulted in kidney failure in animals across the country. The Food and Drug Administration has confirmed 15 pet deaths, and anecdotal reports suggest hundreds of cats and dogs may have died.

FDA testing of the wheat gluten has revealed it was contaminated with melamine, a chemical with a variety of industrial uses, including the manufacture of plastic kitchenware. As late as Monday, FDA officials had said they were uncertain if the contaminated ingredient had been used in any foods destined for human consumption.

Last week, the FDA blocked wheat gluten imports from the Xuzhou Anying Biologic Technology Development Co. in Wangdien, China, saying it was the source of the contaminated product. The agency had refused to identify who had imported the ingredient, used as a protein source.

“Obviously, if this ingredient was responsible, it’s just very upsetting,” Miller told AP.