Walsall Council declare major incident over sodium cyanide spill

A major environmental incident occurred in August 2024 when a significant sodium cyanide spill was detected in a canal stretching across Walsall to Birmingham in the West Midlands, UK. The spill, originating from an industrial site, has raised serious concerns due to the toxicological and ecological ramifications associated with cyanide, particularly its lethal effects on aquatic life and potential risks to human health. 

Sodium cyanide (NaCN) is an inorganic compound used extensively in industrial processes such as metal extraction, electroplating, and chemical synthesis. When dissolved in water, sodium cyanide produces cyanide ions, which are highly toxic. Cyanide ions interfere with the electron transport chain in mitochondria by inhibiting cytochrome c oxidase, leading to cellular hypoxia and death. Even at low concentrations, cyanide can be lethal to aquatic organisms, as observed in the recent spill. 

The UK Health Security Agency (UKHSA) notes that exposure to cyanide salts can lead to symptoms including headaches, dizziness, nausea, and severe outcomes like seizures, respiratory failure, and cardiac arrest in humans. Due to its rapid action, sodium cyanide is considered one of the most hazardous chemicals in industrial use. 

The cyanide spill led to the immediate death of a significant number of fish within a 12-mile stretch of the canal, with over 90 kg of dead fish being removed from the affected area. Sodium cyanide's solubility in water allows it to disperse quickly, resulting in widespread ecological damage. The spill was compounded by the presence of zinc cyanide, further increasing the toxicity of the water. 

The toxic effects of cyanide extend beyond fish, threatening other wildlife such as otters and water voles that inhabit the canal and its surroundings. The long-term ecological impact remains uncertain, as the extent of the spill's penetration into the ecosystem is still under investigation. 

Upon discovering the spill, Walsall Council and multiple partner agencies, including the Environment Agency and West Midlands Police, declared a major incident. An exclusion zone spanning 1 km was established, with temporary dams installed to contain the spill within the most contaminated section of the canal. 

Water testing was initiated to monitor cyanide levels and determine the safety of the surrounding areas. Sodium hypochlorite (NaOCl) was considered for neutralizing cyanide in the water, converting it into cyanate, a less harmful compound that further degrades into carbon dioxide and nitrogen. However, full-scale remediation efforts are still being developed, depending on the ongoing assessment of the spill's impact. 

Public health officials have urged local residents and visitors to avoid the contaminated canal and its towpaths. Direct contact with the water poses serious health risks, particularly for children, pets, and individuals with pre-existing health conditions. Symptoms of cyanide exposure should be addressed immediately by seeking medical attention, with NHS 111 and emergency services on alert for potential cases of poisoning. 

Residents were also warned against consuming any fish caught from the canal, given the risk of bioaccumulation of cyanide in aquatic organisms. The council and health agencies are maintaining a cautious approach, with public safety being the highest priority.