Gas pumped into a street all night after thieves stole copper piping from a plumbing business.
The piping taken from outside the premises of Plumbwise Wales in Skewen was actually used as a live supply gas line, and had been crudely snapped away.
It meant highly inflammable gas continued to leak from the premises on Siding Terrace for nine hours.
The piping was close to an outside smoking shelter at another unit on the street, with only the quick-thinking actions of engineers who discovered the theft in the early morning preventing potential disaster.
Plumbwise Wales director Shaun Hutchings said: "Whoever it was went behind the building and ripped away the gas pipe from the wall.
"We're looking at cameras and we think it was between 11.30pm and 12 on the night of Tuesday, June 22.
"They also tried to get at the main water pipe, but that was only plastic. But it would have been spilling gas for around nine hours - anything could have happened.
"There is a unit next to use that has a smoking shelter around the corner. It's pure luck that nothing more serious happened.
"Fortunately, staff came in early and realised what had happened, and as we are gas engineers we were able to repair it ourselves. It could have been so much more serious and if they sell it for scrap they would probably only get less than a tenner".
