What Does the Prop 65 Warning Label Mean?


Ever wonder why you’re seeing Prop 65 warning labels that tell you the product contains ingredients known to cause cancer or birth defects… on everything from appliances to furniture, the entrance to Disneyland, and at one point even coffee?

They’re almost everywhere now, and the story behind them is an interesting one.

Proposition 65, or Prop65, is a California State law that – thanks to online retail – has now made itself known across the US and Canada.

But what does it really mean? And should you panic if you see it on a product you thought was safe – or hadn’t even considered there might be a concern?

I first started looking into this when I got a new fridge delivered several years ago – to my home in Canada – with the Prop 65 sticker staring me in the face. I looked into it then but didn’t learn about the full history.

Now, it’s time to dig in. Let’s figure out what the deal with the Prop 65 warning label is, and whether we as consumers can use it to choose healthier products.

Keep reading, or you can listen to this on Episode 55 of the Missing Pillar of Health Podcast on your favourite player, or through the player below.


What is Prop 65?

Proposition 65 became law in November 1986, known as the Safe Drinking Water and Toxic Enforcement Act of 1986.It started with the intention of cleaning up California’s notoriously polluted drinking water, with hopes that industry would be forced to stop dumping toxins into waterways. It prohibits the intentional discharge of significant amounts of listed chemicals into drinking water sources – but that’s rarely how it’s thought of today.

Under the law, the State of California must publish a list of chemicals known to cause cancer, birth defects or other reproductive harm, and keep it updated at least once a year.

When it was first published in 1987, it contained 235 chemicals. Today, it has almost 1000 chemicals in the list.

Proposition 65 also requires businesses with more than 10 employees to provide warnings on products, workplaces, rental housing, and businesses if they pose a significant exposure risk to chemicals that cause cancer, birth defects or other reproductive harm.

Because California holds significant market share, the ripple effect of product law in the state spreads across the US and even Canada. Manufacturers who sell in California put the label on the products destined outside the State too, which is why it was on my sold-in-Canada fridge.

What Chemicals Make the Prop 65 List

Examples of chemicals on the list include ingredients in pesticides, common household products, food, drugs, dyes, and solvents. The list includes not only intentionally-added chemicals, but also chemicals that may be used in the manufacturing or construction process, or that can be by-products of chemical processes.

The Prop 65 website states that a warning must be given for listed chemicals unless the exposure is low enough to pose no significant risk of cancer or is significantly below levels observed to cause birth defects or other reproductive harm.

It goes on to state that “Using its knowledge of its business operations and the chemicals it uses, a business can review the Proposition 65 list to determine whether its operations or products are likely to expose people in California to any listed chemicals.”

The agency that oversees Prop65 provides levels of exposure for about one third of the overall chemicals list that do not require a Proposition 65 warning, called the “safe harbour” list.

However, the process of determining exposure is complex and often requires separate expertise outside a regular business employee roster. What’s more, if a business uses a chemical not provided on the safe harbour list, they must provide a Prop65 warning or demonstrate that the expected exposure level will not pose a significant risk.

How is Prop 65 Enforced

  • Prop 65 warnings are required by law in California where exposures are deemed significant.
  • The exposure level is up to the businesses to determine, and not putting a label on a product that requires it can result in fines of $2500 per day of non-compliance for each violation.
  • The body that oversees the law acknowledges that this is a complex process, and says “a business is discouraged from providing a warning that is not necessary and instead should consider consulting a qualified professional if it believes an exposure to a listed chemical may not require a Proposition 65 warning.”

So what seems easier? Ignoring the merely “discouraged” behaviour of slapping a label on everything to avoid fines, or investing in experts and analysis to figure out if the label is required? (That’s a rhetorical question.)

Where It all Went Wrong

For the first 10 years or so, Prop65 seemed to actually do what it was intended to do, and companies did re-evaluate their use of toxins like lead.

However, by the late 90s, lawyers found an opportunity to gain financially from targeting small companies that were operating even just a little bit outside the Prop65 regulations. You see, Prop 65 also allows California residents to file legal action against companies who they believe are in violation of the law. And so, millions of dollars in legal fees have been earned in what’s essentially the toxins version of ambulance-chasing.

And so, to avoid being sued, companies have opted to put warning labels on everything – whether they pose a real and significant risk to the end user or not.

Some critics of the list emphasize that the warnings have thresholds that are unreasonably low. For example, according to one article, for birth defects, warnings are required at one-thousandth of the level at which a certain chemical is shown to cause birth defects.

California takes a much more conservative approach in their risk tolerances than any other North American – and in some cases even European – jurisdiction. Likely to take into account the thousands of different sources of exposure and accumulation of each.

The other factor that I talk about regularly is that we shouldn’t just be focused on the amount in the finished product. If toxins are in the finished product in any amount, it means that workers up the manufacturing chain have likely been exposed to higher levels and when the products are disposed, their cumulative impact on the environment can become a problem. So saying there’s low amounts in the finished product as an excuse for “safety” doesn’t cut it for me.

However, I will acknowledge that these low limits provide another barrier for companies to be willing to invest in analysis only to find that their products are above the limits and have to contain the Prop 65 label afterall.

How We Can Use Prop 65 Warning Labels as Consumers

While the law was created with the best of intentions, practically, it’s not overly helpful to us as end users. As a consumer, seeing the label on a handful of products might allow us to make more informed decisions about what we buy. Seeing it everywhere has made us tune it out – not to mention it’s sometimes impossible to find viable alternatives without the label.

That being said, I still firmly believe that we need to hold companies accountable for the ingredients they’re using in their products and to know what we’re being exposed to – to the best of our abilities.

If you see the sticker, don’t shy away from asking the manufacturer why it’s there. The Prop 65 website has a full listing of the chemicals on the list with a glossary that is a handy quick reference to help you determine if the risk from a particular product is high enough to reconsider alternatives.

But know that the sticker doesn’t automatically mean there are toxins – it could just be the company’s way of covering themselves legally without doing any of the investigative work to figure out what’s actually in the product.

I hope this helps you demystify the Prop65 warning labels so you can make more informed – and less fear-based – purchasing decisions for you and your family.


If you are overwhelmed at all the conflicting information and labels and want trusted advice to help you lower your exposure to toxins in your home, be sure to check out my product guides and mini-trainings like:

You’ll find these and others at greenathome.ca/learn.