The blast occurred shortly after 10pm at a British Gas plant in the Old Town area of Runcorn, near the famous Runcorn bridge across the Mersey.
A nearby residential street was evacuated and police and social services were trying to find alternative accommodation for more than 100 displaced residents. One resident said that at midnight the skies above the town were still "on fire", with huge orange flames.
Cheshire police said a total of nine people were taken to hospital. More than 60 firefighters were still fighting the blaze at midnight but had managed to bring it under control. Firefighters were also monitoring the site of the gas leak to ensure no further leaks occurred.