Shrek-themed glasses in a McDonald's promotion are being recalled because the designs contain cadmium. (U.S. Consumer Product Safety Commission/Associated Press)

Concerns over the toxic chemical cadmium have prompted McDonald's Canada to follow the lead of its U.S. parent and recall promotional Shrek Forever After glasses.

The four drinking glasses portraying characters from the Dreamworks hit movie have been sold at McDonald's outlets since May 21.

The U.S. Consumer Product Safety Commission issued a recall of the glasses in the U.S. early Friday morning after laboratory testing showed cadmium in paint on the glasses.

A Canadian recall was announced a few hours later. In a media notice issued Friday, McDonald's Canada stated its safety standards are among the highest in the world and the recall was "the appropriate course of action."

"It is important to note that the glassware was evaluated by an independent third-party laboratory and determined to be fully in compliance with all applicable Canadian requirements at the time of manufacture and distribution," said Louis Payette, national media relations manager for McDonald's Canada, in a release.

The glasses sold for about $2 each. McDonald's is asking consumers to stop using them and will be issuing instructions on how to return them for a refund.

ARC International of Millville, N.J., manufactured the glasses. According to McDonald's about 12 million were produced and seven million sold. It's unclear how many of those glasses were sold in Canada.

Recall prompted by U.S. politician

Cadmium was found in the glasses after an anonymous tip to U.S. Representative Jackie Speier, who has been leading a campaign to limit cadmium levels in jewelry.

Speier sent samples to the CPSC for further investigation, and levels of cadmium slightly above a protective level proposed by the agency were found.

Cadmium is a known carcinogen that can also cause respiratory and kidney problems. It's been used in paint pigments and as an anti-corrosive material in steel. It's also used in the production of batteries.

Recently high levels of cadmium in children's jewelry from China led to massive recalls.

The concern with cadmium on the McDonald's drinking glasses is that the chemical could leach onto the hands of children and be ingested if they put their hands in their mouths.