Indonesia is investigating radioactive contamination at an industrial zone after US and Dutch authorities found unusual levels of radiation in some of the south-east Asian country’s biggest exports including Nike and Adidas shoes.

Officials in Jakarta say the contamination — first detected in July — originated in a metal-processing factory at the ModernCikande Industrial Estate in western Java and all imports of scrap metal, believed to be the source of the contamination, have since been suspended.

A total of 22 factories were affected, including facilities that process shrimp and make footwear for Nike and Adidas. A clove farm on Sumatra island was also hit, though authorities have not established the source of this particular contamination.