Richie Jones, Wales & West Utilities Gas Emergency Service Manager for South Wales said:
“We have received more than 700 calls reporting a smell of gas along the A470 corridor from Cardiff to Merthyr Tydfil. Our engineers are visiting affected areas, but there are no readings of gas in the air and this smell has not been caused by a leak from our gas network.
"However, if anyone smells gas, thinks they have a gas leak, or suspects carbon monoxide poisoning, they should call us on 0800 111 999. Trained colleagues will take their call, give them advice, and our engineers will be there to help, day or night."