Petroleos Mexicanos started to dismantle a damaged oil drilling rig off the Gulf coast because heat from near-constant fires have made the structure unstable.
Pemex said engineers successfully removed the rig's tower. The company hopes the action will help workers extinguish a raging fire as well as oil and gas leaks that have continued since the Oct. 23 accident that killed at least 21 workers.
The accident was caused by high waves that hit the rig, sending a boom crashing into an oil platform's valve assembly.
The rig is owned and operated by a Mexican subcontractor, Perforadora Central, and was built in 1982 by Bethlehem Steel at the Singapore shipyard, according to the Web site Rigzone.com.
More than 80 workers and rescue personnel were forced to abandon the platform, and most dove into small, enclosed fiberglass lifeboats, some of which broke apart and became swamped. Sixty-three workers were pulled from rough waters by passing ships, but 21 were found dead and one remains missing.
Pemex says the platform has been spilling an average of about 430 barrels of oil per day into the Gulf of Mexico - almost 13,000 barrels to date. Crews have been trying to recover the spilled oil.