About 30 firefighters have tackled a large fire at a caravan park in east London.
Emergency services were called to the blaze on Front Lane in Upminster at about 0815 BST and crews spent several hours fighting the flames.
An ambulance service spokeswoman said two women were treated at the scene for shock. No-one was taken to hospital.
The A127 has been closed in both directions between junction 29 and Front Lane.
'Canons going off'
One local resident, Derek Fawbert, 60, a retired teacher, said: "I heard what sounded like guns or canons going off, seven or eight times.
"It might have been an explosion.
"I looked out the back and there was a plume of black smoke."
London Fire Brigade said there were gas cylinders at the single-storey workshop but could not say whether any had exploded.
A spokesman said: "It's a significant incident but it's not near any houses. It could be protracted because of the cylinders involved."
The cause of the fire is not yet known.