Four workers died including one from Mexican oil services provider Cotemar SA and 16 others were injured Wednesday morning after a fire on an oil platform in the Gulf of Mexico, Pemex said.

Two of the injured workers at the Abkatun Permanente platform are in serious condition, the state-owned oil producer said in a statement. The injured workers are from Cotemar and Pemex, as the Mexico City-based company is known, according to the statement. Three hundred employees were evacuated, it said.

Pemex didn’t provide a reason for the fire, which isn’t yet controlled.

The platform is part of the Abkatun-Pol-Chuc complex, which produced 251,000 barrels of crude and 405 million cubic feet of gas a day from March 1 to March 29, according to weekly production reports from Pemex’s Exploration and Production unit. The complex is between the states of Campeche and Tabasco, about 132 kilometers (82 miles) northeast of the port of Dos Bocas.

Cotemar was installing thermal insulating equipment on the platform, according to a person familiar with the situation, who asked not to be named because of company policy. The platform wasn’t involved in crude production because it is part of a processing center, the person said.