A lorry fire that shut a motorway for 16 hours after it melted the road is believed to be responsible for killing more than 100 fish in nearby rivers, the Environment Agency has said.



Tests are being carried out by environmental officers, with the agency saying the fire caused chemicals to seep into the watercourses. Around 150 fish were found dead at the river Penk near Stafford, while there were further reports of dead fish at the river Sow.



The M6 was closed southbound from junction 13 for Stafford south from about 1.30am on Saturday while the road surface was repaired. Fire covered the carriageway and burned so hot it melted more than 600 square metres of tarmac before the blaze was extinguished at about 3am.



Drivers were stuck in queues up to five and a half miles long, with many of those caught in the delays families going on holiday after schools broke up for the summer. Nobody was hurt in the incident.

The Environment Agency tweeted: “Chemicals and oil has entered the river Penk [at] Stafford after earlier lorry fire.”

A spokeswoman said the agency was unsure what the exact pollutant was, but that fast-tracked test samples were expected back within the next few days. The river Penk is thought to be home to a variety of fish, including trout, chub, perch and pike.

The agency’s officers said they had counted approximately 150 fish deaths and urged people to stay out of the river Penk pending their investigation. They also urged people to stay out of the nearby river Sow, where further dead fish were reported.

In a statement, the agency said: “We’ve been responding to reports of dead fish in the river Penk and river Sow near Stafford. We’ve identified that the pollution which has caused this is the runoff from a lorry fire on the M6 on Saturday.

“Environment Agency officers are working with partners from the Canal & River Trust and Staffordshire police to identify the pollutant and to minimise the impacts on the river. We’re advising members of the public to stay out of both rivers until our investigations are complete.”