New Delhi, Sept. 17: A plan by Indian scientists to build an underground laboratory to study subatomic particles called neutrinos appears to have encountered a fresh hurdle — objections by Kerala’s veteran communist leader V.S. Achuthanandan.

The leader today demanded that the Centre should stop work aimed at setting up the Indian Neutrino Observatory (INO), a laboratory to be built about 1.2km beneath the Bodi West Hills 110km from Madurai, Tamil Nadu.

“The Centre should come out with details of the project ... and discuss environmental and other issues connected with people and scientists before going ahead,” Achuthanandan said in Thiruvananthapuram today.

Speaking to reporters along with Kerala-based environment researcher V.T. Padmanabhan, the CPM veteran said the INO is to be located in Tamil Nadu’s Theni district, which is next to Kerala’s Idukki district.

Padmanabhan claimed that the area is geologically fragile and the digging of a tunnel would require excavation of some 800 tonnes of granite and other soils. “We don’t know whether a geotechnical study has been done to examine the implications of this digging,” he said.

The laboratory, Padmanabhan claimed, would receive beams of neutrinos from the US, which would bring a radiation hazard to the environment and to dams around the laboratory.

Senior scientists associated with the INO project have described such concerns as absurd.

“Hold your hand in the sun and some 400 million neutrinos will pass through it every second — trillions of them pass through us and through everything else on earth day and night,” said D. Indumathi, a physicist at the Institute of Mathematical Sciences, Chennai.

The INO is intended to study the properties of neutrinos produced by cosmic rays in the earth’s atmosphere. There are several types of neutrinos, and one key objective of the INO is to determine their relative masses.

Indian scientists fear that the objections from Kerala might further delay their project conceived about 10 years ago, while China’s own homegrown neutrino studies laboratory was completed within eight years and has been up and running for several months.

The INO project was earlier delayed for nearly two years by objections from the Union environment and forests ministry which had rejected an earlier proposed site which was close to the core area of a tiger reserve.

The Bodi West Hills is an alternative site that has already been approved by the environment ministry.

Padmanabhan has questioned the geotechnical implications of digging a tunnel at the new INO site around which, he claimed, there are several dams within a 40km distance.

But project scientists said the digging would not affect any dams.

“The tunnelling procedures are routine engineering — the vibrations won’t travel more than a few hundred metres. It’s just like building a road tunnel. Tunnels are drilled in our cities for metros — it’s the same engineering,” a scientist said.

Scientists say the INO laboratory, jointly funded by the departments of atomic energy and science and technology, is expected to cost Rs 1,500 crore and will take five to seven years to be built.