According to Sierra Club Canada, studies have found toxins and heavy metals like lead in some face paint.
"If you pick up a package of makeup and it doesn't list all the ingredients, put it back down," advised John Bennett, the organization's executive director.
"Studies have found that cadmium, chromium, lead, other heavy metals, other toxic chemicals — that can get into a child's body by putting these creams on their faces."
Under the federal Food and Drugs Act, it is illegal to import or sell face paints or Halloween costume paints that have lead, cadmium, chromium or other heavy metals in as an ingredient.
But trace amounts can work their way into cosmetics because they're sometimes found in other ingredients.
Bennett said without widespread testing, it's up to consumers to be aware.
"Health Canada doesn't test these products as they come into the country. None of this is actually manufactured in Canada."
'Let the kids have fun'
If toxic levels are present in the body, heavy metals can cause damage to the nervous system and kidneys, among other things, and in children can lead to problems with brain development.
Toronto dermatologist Sandy Skotnicki said there's little cause for worry, however, from using face paint once for Halloween.
"Is that one application of that going to cause any harm? No. And it actually really bothers us as physicians when you get all that fear-mongering. Let the kids have fun," she said.
"There's not going to an issue with one application of Halloween makeup… I think it's good to worry about it for long-term use but not for a night of Halloween."
She said any cosmetic when used for the first time can cause a reaction on someone's skin, especially on the sensitive skin of children, and that might include itching, burning or redness. But "it's not the end of the world," Skotnicki said.Suggest a correction