Chen Yuan-Cheng (4th from left), Chairman of Formosa Ha Tinh Steel Corp., and officials of the company bow in apology to an environment disaster in central Vietnam. Still image captured from a video clip released by the Vietnamese government at a press conference in Hanoi on June 30, 2016

Formosa Ha Tinh Steel Corp. (FHS) has apologized for causing an environment disaster in central Vietnam and promised to pay US$500 million in compensation, the Vietnamese government said Thursday afternoon.

FHS, a subsidiary of Taiwan's Formosa Plastics, has been in hot water over the past two months after hundred of tons of fish washed ashore in April in four central Vietnamese provinces Ha Tinh, Quang Binh, Quang Tri and Thua Thien-Hue. The steel mill is in its final stage of construction in Ha Tinh's Vung Ang Industrial Zone.

More than 100 scientists, including foreign experts, joined an investigation into the mass fish deaths, Minister Mai Tien Dung, Chairman of the Office of the Government, said at a long-awaited press conference in Hanoi Thursday afternoon.

They found out that industrial waste containing phenol, cyanide and iron hydroxides in the water killed the fish. The source of the waste was traced back to FHS, according to Minister Dung.

FHS on June 28 took responsibility for the "serious environmental incident," after multiple meetings between Vietnam's environment ministry and related agencies and FHS as well as Formosa Plastics, Dung said.

The company committed to apologize to the Vietnamese people and government for the disaster and pay VND11.5 trillion (US$500 million) in compensating local people's economic losses, supporting them to find news jobs and treating polluted sea environment, he said.

It also promised to repair its waste treatment system and cooperate with responsible government agencies to monitor sea environment.

FHS would suffer legal punishments if it repeated violations of Vietnam's environment protection regulations, Dung said.

In a letter made public hours before the press conference, Chuan Yuan-Cheng, chairman of FHS, said that the investigation had found that subcontractors' faults during the trial phase of operation had killed the fish.

"We respect the government's investigation results and are cooperating with the authorities to handle and mitigate the consequences," he said in the letter written in Vietnamese.