SHANGHAI (AP) -- Authorities are investigating the cause of an explosion over the weekend that injured dozens of people at the Shanghai factory of a supplier to Apple Inc.
The government formed an investigation group and ordered safety checks at the Riteng Computer Accessory Co. factory, a wholly owned subsidiary of Apple supplier Pegatron Corp., said Gan Shanjun, an official in the information office in Shanghai's Songjiang district.
Critics have taken Cupertino, California-based Apple to task for alleged violations of labor and environmental standards by its China-based suppliers, and the company has said it is working to resolve such problems.
Local media reported that 61 people were hurt by the blast and more than 20 of them hospitalized, but none suffered life-threatening injuries.
"Our hearts go out to the people who were hurt in Songjiang. We are working closely with Pegatron to understand the cause of this accident," said Carolyn Wu, a spokeswoman for Apple in China.
She would not comment further. Apple provides little if any information about its suppliers in China.
Pegatron, in a statement, said the blast occurred in dust collection equipment. Its staff also said they would not make further comment.
The New York-based group China Labor watch said the explosion occurred when aluminum dust from polishing cases for iPads caught fire.
A similar explosion occurred in May at a factory of electronics maker Foxconn Technology Group. Three people died and 15 were hurt due to what Foxconn said was "an explosion of combustible dust in a duct" at the plant in the southwestern city of Chengdu.
Aluminum dust is highly combustible, according to the U.S. Occupational Health & Safety Administration, and some experts have stressed the need to take special precautions in making Apple's trademark shiny metallic cases.
Researcher Fu Ting contributed to this story.