An Avon Fire and Rescue Service spokesperson said that reducing the impact of contaminants in the local environment was “extremely important” to the service.
“We work closely with the Environment Agency, seeking and following their advice to ensure the most appropriate environmental protection measures are in place,” the spokesperson said.
“In line with their guidance, we took steps to prevent contaminants from spreading by blocking drains, containing runoff where possible, and limiting any potential impact on local waterways and surrounding areas.
“At the time we were aware of references to firefighting foam in nearby waterways.
“However, no firefighting foam was used during our response to this incident.”
The Environment Agency said firewater incidents were “complex” and often involved “multiple pollutants”.
The spokesperson added: “Our assessment indicates the eel deaths may have resulted from a combination of factors, including multiple chemicals acting together and the levels of pollution changing throughout the incident.”