Developers planning to build 650 homes on a former asbestos factory site have been told to carry out many more tests.
Developers want to build a housing estate on the site
Plans for the former Turner and Newall site at Spodden Valley have angered local residents who fear health risks.
But an independent report, which cost Rochdale Council £80,000, has outlined the work that must be done if the plan is to go ahead.
Asbestos-contaminated rubble has already been removed following a campaign by residents.
Developers MMC Estates and Countryside Properties has welcomed the report and said it would help them decide what further tests are necessary and what work needed to be done to make the site safe.
But campaigners have also welcomed publication of the report claiming it "vindicated" their opposition to further development.
Ken Smith, from Rochdale Council, said the authority wanted further information.
This included the impact of traffic from any new development and the development mix on the site.
Mr Smith added: "It is important to re-emphasise that it will only be when, and if, we are completely satisfied that all contamination and other issues have been properly addressed, and that the proposals are acceptable in planning terms, would we make a recommendation to the Planning Sub-committee."