A major incident occurred on Wednesday after authorities reported that sodium cyanide had leaked into a canal in the West Midlands, posing a serious health risk to the public.
People are being advised to avoid a 12-mile stretch of canal and towpath in Walsall following the toxic spill, which is believed to have occurred on Monday.
The risk is for people and pets that have direct contact with the canal water. According to to the UK Health Security AgencySodium cyanide may cause headache, nausea, dizziness, nervousness, confusion, changes in heart rate, drowsiness, convulsions, vomiting, low blood pressure, and unconsciousness.
Sodium cyanide consists of “white crystalline solids with a slight almond odor.” It is used, the agency says, “in industry for metal cleaning, plating, metal extraction, and photography.”
Walsall Council said it was notified on August 12 of a spill in the canal at Pleck, which stretches for more than a mile from Spinks Bridge to Birchills Street Bridge. A major incident was declared the following day.
On Wednesday, dozens of dead fish were floating in the canal after the cyanide spill.
Garry Perry, leader of Walsall council, said the priority was the safety of local people. “I share their concerns and hope this incident is resolved as quickly as possible. We are working closely with our partners to bring this situation, which has been declared a major incident, under control. For your own safety, please avoid this section of the canal and towpaths,” he said.
Perry told the BBC it was “a very timely and ongoing investigation”. He added: “Anything that looks like this is serious – particularly because the potential risk to the health and safety of animals and people is always going to raise alarm.”
Walsall Borough Council said the source of the leak has been identified and sealed and an investigation into the cause is underway.
An expert said the leak was “concerning” and that it could take days to fix.
Jonathan Paul, senior lecturer in geosciences at Royal Holloway, University of London, said: “Uncontrolled discharges into waterways pose a major threat to the ecosystem. It also poses a risk to public water supplies if canal water enters leaking plumbing pipes. The biggest risk to people then is through exposure to the toxic canal water, for example through touching it.”
He said high concentrations of sodium cyanide would result in “classic symptoms of poisoning” of nausea, weakness, pain and possibly loss of consciousness. “But that is entirely dependent on how much is ingested and the concentration of the chemical.”
The council a card placed showing the canals that the public should avoid. It included waterways from Walsall Lock Flight to the lock flights at Rushall, Ryders Green and Perry Barr.
People who have come into contact with the canal water in the area and feel unwell are advised to seek health advice by calling 111. In an emergency, you can also call 999.
The council said anyone who caught fish from the canal should not eat it. Drinking water is not affected.
The spill is being treated as a major incident, involving police, fire services, ambulances, councils, the Environment Agency, the UK Health Security Agency (UKHSA), Severn Trent Water and the Canal and Rivers Trust.
The Environment Agency has launched a sampling and testing programme with the aim of reducing the affected area as quickly as possible, authorities said.