By Lauren Kirchner

Live in America, and shop for stuff here long enough, and you’ll eventually see it: A label with the somewhat alarming message that the thing you’re holding in your hands can expose you to a chemical “known to the state of California to cause cancer.” Or one that warns that using the product can expose you to a toxic ingredient that might cause birth defects or other reproductive harm.

How much should you worry when you see such a warning? Here’s a little primer on how the labels came to be and what they might mean for you.

A ‘Right to Know’ Law That Came From Voters

The warnings are a result of California’s Proposition 65—technically called the Safe Drinking Water and Toxic Enforcement Act—a ballot initiative passed by voters of that state in 1986. The idea was to protect Californians from toxic chemicals that cause cancer, birth defects, or reproductive harm—both in their drinking water as well as in everyday products.

The law bars businesses from knowingly dumping significant amounts of dangerous chemicals into water. It also requires them to prove that products containing the chemicals won’t expose a person to more than a maximum exposure limit of that chemical. If they reach or exceed the limit, then the businesses either have to remove the chemical in question from that product, or warn people about it ahead of time. Hence, the warning stickers.

California’s Office of Environmental Health Hazard Assessment (OEHHA) maintains the list of Prop 65 chemicals that it considers harmful, and it updates the list at least once a year. At latest count, the Prop 65 list contained over 900 chemicals.

Added most recently, just in the past year, were three different per- and poly-fluoralkyl substances (PFAS) —a few of the many so-called forever chemicals that break down extremely slowly, and can build up in the human body over time.

These warnings show up on sometimes surprising things: from furniture and appliances, to shoes and cars. California businesses—including bars, dental offices, and theme parks—have to post them, too, if potential chemical exposures lurk within. As commerce moves increasingly online, California products are showing up everywhere now, and the warning labels along with them.

Good Intentions Gone Overboard?

To say there’s been some backlash is an understatement.

On Reddit’s “Ask an American” page, a “mildly concerned Scandinavian” wondered last year if they should be worried about the Prop 65 warning label on a newly purchased computer part. Dozens of people chimed in, nearly all categorically dismissing the concern. “California slaps that sticker on literally everything,” wrote one poster. “It’s a total and complete joke at this point,” wrote another. “The intention was good but really all it actually did was cause prop 65 labels to appear on EVERYTHING,” yet another wrote. “As long as you’re not eating that dvd reader you’re probably fine.”

So how did Prop 65 go from public health idealism to punchline? Experts say that while the policy was originally meant to nudge businesses to reformulate their products to make them safer, most businesses find it is cheaper simply to proactively label products instead. That’s led to the current reality of the California marketplace, where consumers are bombarded by so many warnings that they’ve learned to ignore them.

A 2016 paper from Harvard Kennedy School argues that the current government warning system, including Prop 65, “fails miserably at distinguishing between large and small risks; that is to say between wolves and puppies.” When warnings about small harms (puppies) are too plentiful, people become conditioned to ignore them. This can be dangerous when real dangers (wolves) arrive, but no one’s heeding the warnings anymore. Prop 65 labels indicate that a toxic chemical is present in a given product, but not how high the level of exposure is, and not how relatively dangerous the chemical is, compared with others. For these reasons, the authors write, “Proposition 65 warnings flunk the test of providing accurate or useful information to consumers.”

Aside from the punchline aspect of Prop 65’s ubiquitous warnings, some critics also say that it’s become a bit of a racket. When companies get sued for non-compliance, they often settle them quietly to make them go away, critics say—and this has the effect of enriching lawyers, but not making the marketplace any safer. “Attorney fees account for nearly three-quarters of the more than $300 million that has been paid out in Proposition 65 settlements since 2000,” according to a Los Angeles Times analysis of state data.

The American Chemistry Council, an industry group representing manufacturers of many of the chemicals on the Prop 65 list, did not respond to multiple requests for comment.

Still Better Than Nothing?

There have been some successes, however. An early one came in 1989, when a Prop 65 legal settlement led the manufacturer of Liquid Paper to agree to remove trichloroethylene, a carcinogen, from its original formula. OEHHA’s website touts other wins, like reducing arsenic in bottled water and removing toluene from many nail care products. These are not small victories; prolonged exposure to arsenic can contribute to some cancers and may even lower IQ scores in children, and toluene is a neurotoxin. However, reformulations often fly under the radar.

“Because our intention is the removal [of toxic chemicals], warnings are better than nothing, but they’re not as good as there just not being the need for a warning,” says Kaya Allan Sugerman, director of the illegal toxic threats program at the California-based Center for Environmental Health. “We’d like to see the products not contain these chemicals.”

Sugerman’s organization is very active in bringing legal action against companies for Prop 65 non-compliance, the goals of which, she says, are safer products, not just payouts. She says CEH’s legal actions contributed to the removal of lead from children’s jewelry and imported candy, for instance.

“Prop 65 is kind of like an iceberg…but the warnings are what’s only visible above the waterline,” Sugerman says. “The real impact of the statute is really under the ocean; it’s really the companies that have been compelled, through years and years of new chemicals being added to this list, to reformulate their products.”

This year, Consumer Reports cosponsored a bill in the California legislature that aimed to make those reformulations more visible. The “Public Right to Know Act” would have prohibited secretive settlement agreements that hid information about dangerous products or environmental conditions from the public. The bill passed California’s Senate but failed to pass in the Assembly.

Another important aspect of Prop 65 is the standards themselves—the thresholds set by scientists at California’s OEHHA for what are considered the maximum levels of exposure for each chemical on the list. Several state committees of scientists and the public all weigh in on the addition of new chemicals to the list. These exposure-level standards have proven useful in other contexts. For instance, CR uses those same thresholds to test some foods for safety—like measuring the prevalence of heavy metals in protein powdersjuices, and baby food.

“When we evaluate whether we consider something to be safe or unsafe, we’ve often referred to Prop 65,” says Michael Hansen, PhD, senior staff scientist at CR with an expertise in food safety. “From the consumer viewpoint, you want to be conservative on health, you want to err on the side of safety.”

Read the full article here.