Enforcement of California’s Proposition 65 toxic chemical labeling law has resulted in a significant decrease in the amount of lead found in certain candies and colorful purses, according to a new report.

Lead levels in tamarind and chili candies sold in California declined dramatically following 2004 litigation brought against several manufacturers of the treats, researchers at the Oakland-based Center for Environmental Health found. 

In 2004, almost half of the candies tested contained hazardous levels of lead. That dropped to just 3 percent five years later, following litigation brought against manufacturers by CEH and California’s Department of Justice, the report found.

Meanwhile, about a third of faux-leather purses, wallets and handbags sold in California and online were found to contain lead-tainted pigment in 2009, according to the study. But by 2016, after CEH had sued manufacturers of these items citing Proposition 65 rules, the proportion of lead-tainted purses and bags dropped to 8 percent.

“The key takeaway is that the prevalence of lead contamination in these two categories of products declined markedly after Prop 65 litigation,” said Caroline Cox, a senior scientist at CEH and lead author of the report. “We think it shows that Prop 65 and other similar state laws are an effective way of encouraging companies to make safer products.

Passed by voters in 1986, Proposition 65 requires businesses to place warnings on products that contains chemicals known to cause cancer, birth defects or other reproductive health problems. As part of the regulations, private individuals and organizations such as CEH can sue manufacturers they believe have violated the law.

Lead is one of many chemicals that require a Prop. 65 warning. Lead is highly toxic, especially to babies and young children because they are smaller than adults and still developing. Exposure to lead can cause irreversible brain and nervous system damage, including intellectual disabilities and behavioral problems. Lead can also poison unborn babies if a pregnant woman is exposed to the metal, such as by touching a lead-tainted purse.

According to the Centers for Disease Control and Prevention, poor children from immigrant and racial minority families are at especially high risk for lead exposure. Some of this exposure can happen through consumer products and foods. The tamarind and chili candies tested in the study, for example, are particularly popular among Mexican Americans.

Cox said the candies that tested positive for lead were likely contaminated by chilies dried next to roadways and dirty soil, and from packaging that contained lead pigments. An investigation by the Orange County Register in 2009 found dangerous levels of lead in candies imported from Mexico and sold to children in Southern California at that time. The latest study suggests manufacturers have now taken action to curb lead contamination.

“Nobody wants for their brand of candy to be known as the brand of candy that has a lot of lead in it,” said Cox. “I think companies, when given an incentive, were ready to make the change.”

Prop. 65 has come under fire from critics, who say the law is burdensome to businesses and also confuses and instills unnecessary fear among consumers. Cox said the new report shows that the law is in fact working to reduce people’s exposure to toxins.

Margaret Handley, a professor of epidemiology and biostatistics at the University of California San Francisco, said the study only focuses on two types of candies and doesn’t prove lead isn’t contaminating other candies, foods and consumer products.  Her own research showsthat after the state began regularly testing for lead in candy in 2006, the number of health alerts for lead contamination in these products went up.

Handley said lead has also been detected in candies and foods imported from countries other than Mexico, and from food that arrives from abroad through informal networks such as family and friends. She said the state and local health departments need to come up with a more coordinated way of identifying sources of lead poisoning in particular communities and effectively warn people about them.

“There should be a more intentional approach,” she said.