The Environment Agency are sampling the tributaries of the River Plym after a fire broke out last night.
About 13 properties in Wotter were evacuated after the fire started in a barn on Higher Bughill Farm filled with tonnes of ammonium nitrate-based fertiliser.
The police set-up an 800m (2,625ft) exclusion zone around the site last night.
The fire service tackled the fire from a distance because of the risk of explosion. The barn has partly collapsed.
Environment Agency officers are monitoring water quality downstream of the incident within the River Plym catchment. This is for ammonia levels which can be poisonous to fish in high concentrations.
The water sampling results suggest that only low concentrations have been found in the firewater and the fire has caused no environmental impact to local watercourses.
‘Initial results from sampling suggest that the environmental impact will be minimal. We had initially advised people to limit recreational water use in the River Plym as a precautionary measure but it is now unlikely that the water quality has been affected,’ said Jon Snowden for the Environment Agency.
The Environment Agency will continue to work with the other partner emergency services to evaluate the impact of the fire.
(from a press release)