Products must state if they contain chemicals tied to cancer or other risks. As a result, manufacturers have pulled back from using the chemicals, researchers found.

The warnings, on thousands of products sold in California, are stark.

“Use of the following products,” one label says, “will expose you to chemicals known to the State of California to cause cancer, birth defects or other reproductive harm.”

Now, new research shows the warnings may be working.

A study published Wednesday in the journal Environmental Science & Technology found that California’s right-to-know law, which requires companies to warn people about harmful chemicals in their products, has swayed many companies to stop using those chemicals altogether.

As it turns out, companies don’t want to sell a product that carries a big cancer warning label, said Dr. Megan Schwarzman, a physician and environmental-health scientist at the University of California, Berkeley School of Public Health and an author of the study.

Keep reading this article on The New York Times Energy & Environment.