Thieves are putting lives at risk by stealing copper gas pipes.
Two homes in Loughton have been targeted in the last week.
The piping was stolen from a house in Hanson Drive overnight on Thursday or Friday.
Thieves also struck at a home in Hillyfields yesterday morning between 8.30am and 10.30am.
There were no reports of injuries.
A police spokesman said: “The theft of gas pipes is extremely dangerous and any gas leak could have serious consequences.
“Anyone with information should contact police on 101.”
“Anyone who sees unauthorised people removing gas pipes should call 999 immediately.”