CARACAS, Venezuela — A natural-gas platform sank off Venezuela on Thursday after workers escaped in lifeboats and the last few leaped into the Caribbean Sea. The oil minister said there was no threat to the environment and all 95 workers were safely evacuated.

Oil Minister Rafael Ramirez told state television that workers disconnected a tube leading from the gas fields to the Aban Pearl platform, preventing any leak or harm to marine life. He said alarms went off three hours before the sinking, giving the crew time to evacuate.

Many stepped into lifeboats and drifted free, said Abraham Natera, the rig’s superintendent. Ramirez said the Indian captain and two assistants, including an American, stayed behind until the platform was badly tilting and about to collapse, and then hurled themselves into the water.

The navy picked up the evacuees using a frigate and boats.

The Singapore-flagged platform, built in 1977, has a capacity of 98 people and is owned by a subsidiary of the Indian company Aban Offshore.