Fire services were called to a gas leak from a 1,000 litre tank on farmland near Chorley yesterday (5 January).
The leak happened in the vicinity of a static caravan on Bolton Road in Withnell at around 11.30am, say fire services.
Fire crews isolated a valve on the LPG tank to stop further leakage.
A spokesperson for the Lancashire Fire and Rescue said: "This was a potentially serious incident as there was a risk of explosion if the gas had found an ignition source.
"Fortunately, we were able to isolate the valve to stop the leak.
"If you suspect a gas leak in your own property, you should ventilate as best you can, avoid ignition sources, remove yourself from the property and call the fire service for assistance."
A woman who had inhaled some of the gas was given a precautionary check-up by paramedics.