A new study finds unsafe levels of lead and cadmium in some popular candy.

(Photo: François Lenoir/Reuters)
 That shiny Valentine’s Day box of chocolates might come with a toxic dose of heavy metals, according to consumer group As You Sow, which on Wednesday accused some of the country’s top chocolatiers of violating California’s Proposition 65 toxic warning law.

Using an independent lab, which conducted three rounds of tests, As You Sow foundthat 26 of 42 chocolate varieties evaluated contained levels of lead or cadmium high enough to be considered unsafe by state standards. Serving-size samples contained lead levels as high as 5.9 percent above the safe limit and cadmium levels as much as 8.2 times above the limit.

This is the second salvo in As You Sow’s chocolate war. On Wednesday, the watchdog filed notice against Hershey’s, Mars, and See’s Candies. The move follows a filing last summer that named 13 other chocolate makers, including Godiva, Lindt, and Ghirardelli, and documented toxic levels of cadmium and lead in some of their sweets.

Prop. 65, a ballot initiative approved by California voters in 1986, requires companies to disclose the presence of chemicals in their products that are known to cause cancer, birth defects, or reproductive problems.

“We want consumers to be aware there are toxic heavy metals in chocolate so they can make better choices,” said Eleanne van Vliet, As You Sow’s toxic chemical research director. “Even tiny amounts can be dangerous because they accumulate in the body over time.”

It’s not just the big, conventional candy companies that are accused of making heavy metal–tainted chocolates: Whole Foods, Earth Circle Organics, and Trader Joe’s also made As You Sow’s list.

How the metals are getting into the cacao is complicated, said van Vliet. Possible culprits include industrial pollution, mining, and the manufacturing process.

In response to As You Sow’s report, the National Confectioners’ Association, an industry trade group, said that because lead and cadmium are elements that occur naturally in the Earth’s crust, traces of the heavy metals are unavoidable in many foods. While cocoa beans, like many other plants, may contain small amounts of heavy metals, chocolate and cocoa are safe to eat, the organization said.

Lead is a neurotoxin, posing extreme risk to children’s brain development, among other things. Experts consider lead so dangerous that there is no safe limit for children. According to the Centers for Disease Control and Prevention, even very low lead levels have been shown to decrease IQ and increase the risk of ADHD and learning problems.

The health dangers of cadmium haven’t received as much attention, but recently this heavy metal hit the headlines as well; it was implicated in research showing that it appears to accelerate cell aging.

Read More: takepart.com – Is Your Valentine’s Day Chocolate Contaminated With Toxic Metal?