A Chinese customer walks past a poster for the reservation of the iPhone 4 in an Apple Store in Shanghai, China, 9 October 2010.. (Weng lei/WENG LEI - IMAGINECHINA)

Chinese officials are investigating an explosion last weekend at another factory in China that makes components for Apple products.

Apple supplier Pegatron Corp. said in a statement that the explosion at the Shanghai factory occurred in dust collection equipment, the Associated Press reported Tuesday. The wire service said local media reported that 61 people were hurt and more than 20 hospitalized but that none had life-threatening injuries.

The explosion rocked the Riteng Computer Accessory Co., a wholly owned subsidiary of Pegatron, in Shanghai’s Songjiang district. The early details of the blast appear to closely mirror a blast at another Apple supplier’s plant earlier this year.

In May, an explosion at a Chengdu plant run by Foxconn killed three workers. The accident was believed to be caused by combustible dust in an air duct. Buildup of aluminum dust had been flagged as a workplace hazard just months earlier by a labor advocacy group called Student and Scholars Against Corporate Misbehavior.

Apple has faced scrutiny from such groups in the past for the labor practices at companies — particularly Chinese companies — that produce components for its popular consumer technology gadgets. In its 2011 Supplier Responsibility 2011 Progress Report, Apple said that it asked for an independent suicide prevention review of the conditions at a Shenzhen plant and was investigating a report that workers at a different company had been exposed to unsafe chemicals.

Apple did not immediately respond to a request for comment on the Shanghai explosion. Company spokeswoman Carolyn Wu told the AP in China: “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.”

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