As McDonald’s begins to offer refunds for Shrek glasses, consumers grow increasingly aware — and concerned — about Cadmium.

Starting today, McDonald’s is offering $3 refunds to customers who bought Shrek drinking glasses recalled because they were tainted with Cadmium. At this point, whether China is to blame for the issue is “very unclear,” says L.A. Times business columnist David Lazarus. According to McDonald’s, the suspect paint used in the product came from France.

Congresswoman Jackie Spear, who first received the anonymous tip about the Shrek cups, doubts Europe is the Cadmium culprit due to its strict manufacturing rules. Spear suspects either a subcontractor or ingredient provider in China; China is one of the leading Cadmium producers in the world.

Lazarus notes that Cadmium has probably stayed off the radar for so long because people weren’t widely aware of its use. The focus has primarily been on the danger of lead products, and lead product replacements weren’t a primary concern. Chinese manufacturers began using Cadmium insted of lead to get the same vivid pigments in product colors.

Spear says she has legislation in the works that would expand the Cadmium ban in U.S., specifying removing its use in any product for children. The Consumer Product Safety Commission plans to have new rules in place — at least for public scrutiny — by the end of summer.