A four-year clean-up operation at the former Avenue Coking Works site in Wingerworth is due to start in August, following confirmation from the Treasury that the £172.3m needed for the project has been approved.

But environmental campaigner John Gower, who lives opposite the 98-hectare site on Derby Road, has raised concerns about the clean-up because of the possible effects that chemicals found on the site could have on residents' health when they are disturbed.

For years he has campaigned for better health protection measures through his group, Communities Opposed to Environmental Pollution, and he wants to see increased filtering of tiny chemical particles because there are around 20 chemicals known to be dangerous to health present at the site.

"The end result is that there's going to be a number of people who will get affected by it, there's no doubt about it," he said.

He added: "I'm not against the clean up — I just want them to do it as safely as they possibly can."

Mike Fenton a project director from East Midlands Development Agency (emda) — which owns the site — said all emissions from the site would be regularly monitored during the clean-up.

"We take the treatment of the contamination on the Avenue site very seriously indeed and are committed to safeguarding the environment and the health of the local population," he said.

The long-term plan for the Avenue is to create a mixed-use housing and commercial property development with a nature reserve and recreational facilities, as well as a flood relief scheme to help protect Chesterfield from the risk of flooding from the River Rother.

Betty Hill, spokesperson for the Avenue's Community Liaison Group, said residents had a real interest in seeing the site change for the better.

"I'm sure I speak on their behalf in saying how pleased I am to hear that this important milestone has been reached," she said.