A new study by the U.S. Food and Drug Administration found lead in 400 shades of lipstick, including popular brands like L'Oreal and Cover Girl.

The lead levels were higher than what the FDA found in a smaller batch of lipsticks tested in 2007.

Lisa Muswagon, a model, was shocked to hear some of the lipstick brands she uses contain lead. "It's pretty scary, considering it's worn on our lips. We lick our lips and we eat," she said.

So what are the worst offenders?

Maybelline Color Sensational in Pink Petal contains 7.19 parts per million of lead, while L'Oreal's Color Riche in Volcanic isn't far behind with 7 parts per million. That's nearly seven times the average amount of lead normally found in lipsticks.

In addition, more than four parts per million of lead were found in 10 well-known brands, including Cover Girl, NARS and Revlon.

But Canadian officials say there's nothing to worry about; all of the tests showed lead levels well below the government-mandated limit. In Canada, the limit for lead in cosmetics is10 parts per million.

"A person would have to, for instance with lipstick, eat – and I mean consume – several tubes of lipstick a day to get anywhere near an exposure of concern," said James Van Loon of Health Canada.

But some environmental activists say any amount of lead is too much.

Maggie MacDonald of Environmental Defence, an environmental activist organization, warns of the dangers of even trace amounts of lead.

"We know it causes birth defects," MacDonald said. "Lead crosses the placental barrier quite easily. We know it's quite harmful for children."

Health Canada says it routinely checks cosmetics for heavy metals, including lead. It is illegal to intentionally add lead to lipstick, but lead is naturally found in some pigments. And Health Canada says it's virtually impossible to eliminate it.

As a mother of two, Muswagon said she'd like to see mandated warning labels on lipsticks in the future. "Probably more awareness needs to be created," she said.

Right now, Health Canada requires cosmetic companies to list ingredients on their packaging, and if a product were found to contain high levels of lead, it would be pulled from shelves.

If you're still concerned about lead in cosmetics Environmental Defence says to look for brands that are made with fruit-based pigments. These are less likely to contain the heavy metal.