Brazilian labor prosecutors are suing Chinese electric vehicle maker BYD and two contractors over allegations of slave labor and human trafficking at the construction site of a manufacturing plant.

The lawsuit describes "degrading” conditions at facilities in Bahia maintained by BYD, China Jinjiang Construction Brazil and Tonghe Equipamentos Inteligentes do Brasil Co. — currently named Tecmonta Equipamentos Inteligentes Brasil Co. It also alleges irregularities with the visas used to bring the workers into Brazil and the confiscation of their passports.

Prosecutors said that in December, 220 Chinese workers were found in conditions "analogous to slavery” and described them as victims of international human trafficking. They filed the lawsuit seeking more than 257 million reais ($46 million) in damages after the companies refused to sign a conduct-adjustment agreement, they said.