OTTAWA – The federal government is looking to stave off the threat of a powerful new street drug its users have christened “grey death.”

Health Canada is seeking stakeholder comments on a proposal to add a deadly new compound, known formally as U-47700, to the Controlled Drugs and Substances Act.

A posting in the Canada Gazette says U-47700 is being used by drug manufacturers in counterfeit prescription medications, as well as in other illicit drug mixtures such as cocaine and heroin.

“Grey death” — named for its resemblance to concrete powder — is a combination of U-47700 and opioids like heroin, fentanyl and carfentanil, an elephant sedative.

The government says U-47700 was detected in at least 254 law enforcement seizures identified by Health Canada in 2016.

This March, the United Nations Commission on Narcotic Drugs voted in favour of controlling it under the Single Convention on Narcotic Drugs.

As a signatory to the 1961 treaty, Canada is required to adopt controls over the substance.

U-47700 was initially developed as a potential pharmaceutical ingredient in the late 1970s. It was never developed for use as a medicinal drug, and has no known legitimate use apart from scientific research, the Gazette posting says.

The government also says more than 130 Internet user reports and more than 40 reports of fatal and non-fatal overdoses indicate U-47700 is being used as a recreational drug in Canada and around the world.

From April to June 2016, three non-fatal overdoses reportedly associated with U-47700 occurred in Canada.