VANCOUVER - Police in B.C. are reluctant to tell the public what unique markings are on ecstasy pills suspected to contain a lethal additive linked to five deaths in the province .

That's because they don't want users thinking they're sanctioning the rest of the pills.

Toxicology reviews of 18 deaths related to the party drug since the start of 2011 found the additive PMMA present in the systems of three men and two women.

The drug is also linked to five recent deaths in Calgary.

B.C.'s chief coroner says police agencies have decided against putting photos of the drug online.

Lisa Lapointe says authorities want people to know that at any ecstasy tablet can be contaminated with anything.

PMMA is considered several times more toxic than ecstasy's usual ingredient and can heat up the body to the point of severe brain and organ damage or death.

The drug has also been linked to five recent deaths in Calgary.