TORONTO - Ontario Provincial Police are joining the fight to educate the public about the dangers of fentanyl, which has been linked to more than 500 deaths in the province over the past five years.

The force is releasing public service announcements and says it will post or link content to its Facebook and Twitter accounts in an effort to make the public aware of the threats posed by fentanyl and similar opioids.

Fentanyl is legal when prescribed by a doctor for chronic pain management, and is roughly 100 times more potent than morphine and about 40 times stronger than heroin.

A lethal dose of pure fentanyl is as little as two milligrams -- the weight of 32 grains of table salt or seven poppy seeds -- and police say many people are ingesting it unknowingly.

Police say drug dealers are adding illegally obtained fentanyl to other drugs they sell -- like cocaine and counterfeit oxycodone tablets -- to increase their profits and this is increasing the number of overdoses and deaths.

An online awareness campaign supported by the Ontario Association of Chiefs of Police offers information about short-term fentanyl antidotes at www.facethefentanyl.ca.