Fifty-four Myanmar migrant workers died, suffocating in the sealed container of a truck that was illegally transporting them to Thailand, where they were supposed to work as illegal laborers.

Thai police said on Thursday that they discovered 121 people had been compressed inside a sealed seafood container. Because the air conditioning failed, 54 of them, including 37 women and 17 men, suffocated and collapsed. The other 67 were rescued and more than 20 of them were taken to a hospital.

The workers declared they got very scared when they realized they did not have enough air, so they started to shout and bang on the sides of the container, but the truck driver had no reaction.

“No matter how many times we hit the container, the driver did not pay any attention,” a survivor complained on Thai television.

The survivors said they had realized from the beginning that the container was very hot and had asked the driver to turn on the air conditioning, but he said it was broken.

When the truck driver realized the problem had gotten serious and some of the workers had died, he parked by the side of the road, unlocked the container and ran off. Police are currently searching for him.

When questioned by the police, the truck owner said he did not know his truck was used in illegal purposes, so he was not arrested. But the survivors of the incident were all held by the police.

More than one million Myanmar workers are estimated to work illegally in Thailand. Last year, 11 Myanmar workers died on their way to Thailand, when the truck transporting them crashed near the Thai border.

Several accidents happen each year, leading to the death of many migrant workers, but that does not discourage them from trying to obtain a better life.

Illegal laborers are usually badly treated and exploited by their employers, being paid a minimum wage.