Up to 2,000 people have signed a petition against proposals to transform a disused mine into a store for low-level hazardous waste.
The mines have been closed for 30 years
NPL Estates is to carry out tests at the former Anhydrite Mine in Billingham to determine if the site is suitable as a long-term disposal facility.
In the 1980s, residents successfully defeated plans to use the mine as a store for nuclear waste.
Now locals want assurances over what could be dumped at the site.
Simon Towers, managing director of NPL Estates, said there were no plans to resurrect the controversial scheme put forward by government agency Nirex.
He said: "I stress it is nothing to do with the previous proposals and we have given public commitments on that fact.
"If the mine is suitable (for low-level hazardous waste), we will consult with the public widely."
The firm believes the mine could be suitable for the disposal of a variety of materials, including building rubble and ash from local industrial facilities.
It has agreed conditional terms to take over responsibility of the mine from its owners ICI.
Fiona Hall, Liberal Democrat MEP for the North East, said testing at the site had raised anxiety in the local community.
She said: "There are a lot of questions to be answered about the nature of the tests and about exactly what waste substances the authorities are so keen to get rid of into the mines."
The petition, started by Billingham Labour Party, will be handed into the mayor of Stockton Borough Council on Wednesday.
Site investigations are expected to take a number of months and the findings will be presented to the council and a series of public exhibitions.
By the time of its closure in 1971 the mine's underground workings stretched two miles from north to south.
The mine, which produced anhydrite mineral for use in the chemical industry, was eventually decommissioned in 1978.