The US Department of the Interior has issued a notice to offshore operators requiring them to permanently plug nearly 3,500 non-producing wells and dismantle about 650 oil and gas production platforms in the Gulf of Mexico.
The department said the risk of damage to unused oil wells and non-producing platforms increases substantially during the hurricane season.
Companies have been reluctant to seal wells permanently as they add value to leases and can potentially be used to support other active wells.
According to the notice, any well with a sub-surface safety valve that has not been used in five years must be sealed. Associated platforms and pipelines must also be dismantled if no longer involved in oil or gas exploration or production.
Oil and gas companies have 120 days to submit a company-wide plan for decommissioning the affected facilities and wells.
Secretary or the Interior Ken Salazar said that the regulations would help to improve safety and environmental protections on the outer continental shelf.