California’s Proposition 65, from 1986, is the basis for many of these product recalls because it forces companies to prove their products are safe or warn consumers about the potential harm. Few companies want to admit their product may cause cancer. Prop. 65 settlements have been responsible for retooling thousands of products over the past 25 years, and most of the time, manufacturers do so voluntarily for their entire product lines across the country.

Down by law: It's unusual that Prop. 65 must be enforced by lawsuit. No regulator is responsible for forcing compliance, so consumer and health advocacy groups often must threaten lawsuits before they affect change.

Get the lead out: For years environmental groups targeted lead in products, and now they are moving on to other heavy metals. Expect to see more products tested for a wider variety of toxics.

Multiple U.S. agencies consider cadmium toxic. According to the Center for Disease Control, breathing high levels of cadmium can cause severe lung damage; eating high levels can cause serious gastrointestinal problems; long-term exposure to lower levels can lead to kidney disease, lung damage, and fragile bones. The U.S. Department of Health and Human Services considers cadmium and cadmium compounds to be human carcinogens. Prenatal cadmium exposure in animals has caused behavioral, developmental, and neurological defects. So ideally, you don't want cadmium anyplace it could be touched by a child, but you'd also want to make sure the people making these products or dealing with their disposal are not exposed.

Why cadmium? Cadmium is really useful for jewelry making. It's a soft metal that can be used either as a solder or as a filler. It has been used for ages so people know how to work with it. And it's plentiful and relatively inexpensive. From a regulatory perspective, until recently, cadmium has taken a backseat to other heavy metals, such as lead and mercury.

What now? Now that California is among the states with cadmium restrictions, joining so many international restrictions on cadmium use, manufacturers will likely keep it out of accessible parts and surfaces and coatings. But given the complex and often convoluted nature of supply chains, testing will have to be vigilant to make sure these restrictions are actually followed.