A plan by oil giant Shell to store 300,000 tonnes of carbon dioxide a year in a depleted gas reservoir beneath Barendrecht, in Holland, has drawn the ire of residents and local officials who have vowed to thwart it.

"We are going to do everything to oppose this project," declared Barendrecht deputy mayor Simon Zuubrier, who voiced fears for the safety of the city's 50,000 inhabitants.

"We are taking legal action to get it cancelled and we'll approve none of the required permits."

Anglo-Dutch Shell in November was authorised by the Dutch government to undertake a project to capture and store a portion of the five megatonnes of carbon dioxide emitted each year by the company's refinery in Pernis, Europe's largest. Pernis is located 15 kilometres from here.

Under the scheme, set to get under way in 2012, the CO2 will be carried by a pipeline and, after being compressed, will be injected into a depleted gas reservoir 1,800 metres under ground. The reservoir has a capacity of 800,000 tonnes. Shell has said that over time the CO2 will dissolve or form minerals.

With a positive evaluation of the initiative by government-mandated experts, the project will be extended in a few years to another nearby gas reservoir, with a nine- megatonne capacity and part of which lies under Barendrecht city centre.

"It's ridiculous to carry out such an experiment in a densely populated area," insisted Mr Zuubrier.

Klass Brantjes, a member of a residents' association, said that while "we have been given the illusion of security, all the risks are not known".

"The risks that CO2 will escape are real and are especially dangerous as the city is situated in a basin."