ROADS were closed for several hours after sodium cyanide leaked from a tanker.

About 40 firefighters worked for more than four hours to clear up the chemical, which leaked from the tanker in three locations near Portrack Lane interchange, on the A19.

Traffic had to be diverted from roads in the Haverton Hill area of Stockton, including the A19 sliproads, from 8.20pm on Sunday.

The caustic substance leaked for about 25 metres along Haverton Hill Road, at its junction with New Road, Port Clarence.

There was a 50-metre long spillage on to the Portrack roundabout and a small spillage on the A19 sliproad from the roundabout.

Stockton fire station manager Peter Dicks said that as soon as the sodium cyanide hit the road surface, it crystalised, making it less dangerous than in liquid form.

However, he said, firefighters still needed to liaise with the Environment Agency and the Department for the Environment, Food and Rural Affairs to make sure it was washed away safely.

He said: "It appears the tanker had a leak of sodium cyanide at two main sites after it left the Lucite International site, on New Road, in Port Clarence, where the chemical is produced. We do not know exactly how it came to leak.

"The tanker had either been over-filled, or some chemical had maybe just leaked out, but we had to make sure the tanker was sealed tight again once we had cleaned up the surface.

"This chemical can be dangerous, but in this crystalised form it is not so bad as it is not gassing off, and it was easy for us to spot.

"The biggest problem was cleaning it up and preventing people from going through it.

"It was just a case of closing all the roads and using copious amounts of water to wash it away."

He said there was no danger to people or the environment, and the roads were re-opened at about midnight.

A police spokeswoman said: "A number of roads were closed off for several hours while the fire brigade removed the spillage, and we would like to thank drivers and residents for their patience and understanding."

No one from Lucite International was available for comment.