We have been made aware from Merseyside Police of reports that a contaminated form of Heroin, described as “Black Tar”, is currently in circulation.

What has been reported?

Merseyside Police have informed us that a contaminated form of heroin, known as “Black Tar”, is currently in circulation across Merseyside. There are also reports of particularly potent strains of synthetic cannabinoids (spice), known locally as “Fish” and “Black Mamba”, circulating in the area. We are also aware of reports that ketamine may be being mixed with other substances.

At least one death has been linked to these substances. We share this with care, and our thoughts are with everyone affected.

When did this happen?

This information was shared with us by Merseyside Police on Friday 27 March 2026.

Where did this occur?

Reports cover the whole of Merseyside, including the Wirral.

What we know

“Black Tar” is a form of heroin that is believed to be contaminated with fentanyl, a synthetic opioid that is many times stronger than heroin. Even a very small amount of fentanyl can cause a fatal overdose, and it is impossible to tell from the appearance of a drug whether fentanyl is present.

There are also reports that ketamine is being mixed with other substances, which may increase dependency risks for people who use it.

“Fish” and “Black Mamba” are street names for potent strains of spice (synthetic cannabinoids). These can cause severe and unpredictable reactions including unconsciousness, seizures, and breathing difficulties.

Why is this concerning?

Fentanyl-contaminated heroin carries an extremely high risk of overdose. People may not know their supply has been contaminated. A dose that would normally be manageable can become fatal. Potent spice variants can also cause sudden and severe reactions, with little warning. The mixing of substances makes it very difficult to predict how a drug will affect someone.

Harm Reduction Advice

Drug supplies change, best test first

What you buy is not always what it’s sold as, and strength varies a lot.
Start with a small test dose first.

Naloxone: get it, carry it, use it

Naloxone does not work on ketamine or cocaine, but it does work if opioids are also involved.
As the drug supply is unpredictable, it is still vital to carry it.
If someone collapses, give naloxone and call an ambulance.

Do not use alone

Always try to use with people you trust. If something goes wrong, someone needs to spot the signs and call for help.

Recovery position saves lives

While waiting for help:

Check they are breathing
Clear their airway
Put them in the recovery position

Look out for your mates

Signs of overdose include:

Loss of consciousness
Snoring, gurgling, or raspy breathing
Very slow, shallow, or stopped breathing
Blue or pale lips or fingertips

If in doubt, call 999 immediately.

Consider drug support

Being in treatment reduces the risk of overdose and gives you access to ongoing health support.

Drug checking and testing strips

Wirral Ways offers free drug checking resources, including:

Medetomidine and xylazine testing strips
These detect powerful sedatives increasingly found in the drug supply. They can cause profound sedation, slowed breathing, and loss of consciousness, particularly when mixed with other substances.
Nitazene testing strips
Nitazenes are extremely strong synthetic opioids. Even very small amounts can significantly increase the risk of overdose and may be present without a person’s knowledge.

Testing strips cannot make drug use safe, but they can support informed decision-making and harm reduction.

For professionals, partners and people supporting those who use drugs

Please be alert to:

Any client, patient or service user presenting with an unusually severe or sudden reaction after drug use, particularly opioid overdose symptoms
Any reports of unusually potent or strange-looking heroin, spice or ketamine in your area
Any concerns about increased overdose risk among the people you support
Individuals who may not be aware their supply could be contaminated

If you become aware of these substances circulating and have information about locations, please submit this via the Merseyside Police Partner Services portal.

For people who use drugs

To try and reduce your risk of an overdose and related harms:

If you use heroin, use less than usual. Start with a much smaller amount than you normally would. You cannot tell from looking at it whether it contains fentanyl.
Do not use alone. If something goes wrong, you need someone there who can call for help.
Call 999 immediately if someone loses consciousness or stops breathing normally. You will not get in trouble for doing this.
If you use spice, be aware that the strength can vary significantly between batches. What feels normal one time may be much stronger the next.
Avoid mixing drugs, including alcohol. Mixing increases the risk of a serious reaction.

Key Reminders

Naloxone reverses opioid overdose and can save a life. If you use opioids, or you are around people who do, please carry it. You can get a free naloxone kit from any of our hubs — no appointment needed. Find out more about naloxone and our hub opening times here.

Always call 999 in an emergency. Naloxone buys time — it is not a substitute for medical help.

If you hear of contaminated drugs, bad reactions, or positive test strip results

Please report this to Wirral Ways as soon as possible so we can help keep people safe.

Make an anonymous report

Over 18s Support

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Under 18s Support