Herts Police have issued a warning to users as they investigate a “hazardous batch of heroin” circulating in Watford.

The force believes that criminals are supplying synthetic opioids under the guise of heroin. These are often far more potent and could lead to overdose, cardiac arrest, or death.

Several people have apparently suffered medical episodes after taking suspected synthetic opioids in the town.

While police are “working hard” to minimise the substances’ availability they issued an urgent safety warning to make people aware of their circulation today (March 12).

Watford Chief Inspector Andy Wiseman said: “We would never condone the use of illegal substances, we are realistic and understand that people do suffer with addictions, so it is our duty to warn them that there could be a dangerous substance in the drugs they are taking.

“Keeping people in Hertfordshire safe from harm is paramount to our role as the police.

"This means issuing this warning so people are able to make an informed choice and exercise caution.”

The force has already recovered some of the dangerous substances and has made three arrests as part of its ongoing Class A drug supply investigation in Watford.

However, it noted that the three arrests are not being treated as linked to the reported medical episodes at this stage.

The county’s community safety unit offered the following advice:

  • Go low and slow - Be extra cautious about the sources from which you get your drugs, and about the drugs you are taking; maybe starting with just a quarter hit of a new supply.
  • Do not use alone: make sure that someone you trust is present and equipped with a couple of naloxone kits.
  • If using with others, it’s best if only one person uses the drug first and uses less as a test dose.
  • Don't mix drugs: Using more than one drug increases your risks of overdose, including mixing with alcohol.
  • Naloxone won’t work on non-opiate drugs but it’s always worth having kits available anyway. If in doubt you can use naloxone in any overdose situation. There have been reports of increased doses of Naloxone needed when drugs contain synthetic opioids.
  • Look after your friends: look out for the signs of an overdose, e.g. loss of consciousness, shallow or absent breathing, ‘snoring’ or loud ‘rasping’, and/or blue lips or fingertips.
  • Be prepared to call immediately for an ambulance if you suspect someone has overdosed.