A controversial bungalow will only be built in an Ilkeston back garden if no former mine workings are found on the site.
A meeting of Erewash Borough Council heard that if, after a coal mining risk assessment, former mining works are found on the site in New Lawn Road, applicant James Fitch will have to pay to rectify them or abandon his plan.
Neighbours were also concerned.
Chris Jolly said there could be methane gas beneath the ground in mining works, which date back the 1800s.
“If this bungalow is built, what’s going to happen to this gas?” he asked.
Councillors voted eight to one in favour of the plan.