The US House of Representatives Energy Committee has voted through the scheme to build a high level waste repository in Yucca Mountain, Nevada, 144 km north of Las Vegas, in spite of a rejection of the scheme by the Nevada state government. The decision must now be put to a vote in both the House of Representatives and the US Senate to win approval.

Under US regulations the decision by Nevada to veto the plan can be overturned if both houses of the US legislature vote to approve the scheme. There is broad support in the House of Representatives but the fight is much closer in the Senate. If the scheme is approved it will provide the USA with a central repository for nuclear waste – essentially spent reactor fuel – able to accommodate 70 000t of radioactive material.

The US Energy Secretary has said he is convinced by scientific studies to date that the waste, which will be active for 10 000 years, will be safely stored. However critics claim that many questions remain unanswered, including the frequency of volcanic events and thermal, mechanical and chemical interactions that could affect the surrounding rock. The design for the repository has yet to be decided, making it difficult to evaluate fairly.

Others have expressed concern about the safety of transporting nuclear materials over great distances. The counter argument is that there have already been thousands of shipments across the USA without accidents involving nuclear release.