Two workers were killed and three injured by an ammonia leak Tuesday at a Malaysian chemical plant, the company said.

Two workers were killed and three injured by an ammonia leak Tuesday at a Malaysian chemical plant, the company said.

"Five contractors were affected. The company however regrets to inform that two fatalities have been reported," Petronas Chemicals Group said in a statement.

The firm is a unit of state energy group Petronas. The leak happened at its plant in the eastern state of Sabah.

Petronas Chemicals produces a range of petrochemical products including olefins, polymers and fertilizers.

The company said the leak had been contained and authorities are investigating the cause.

Petronas is Malaysia's only Fortune 500 firm and the single largest source of government revenue and of national export earnings.