A Hong Kong advocacy group says last week's explosion at a Chinese factory that makes Apple electronics was due to management negligence, and not a simple accident. 

Last week, an explosion at a factory owned by Foxconn in Chengdu killed three workers and injured 15. Students and Scholars Against Corporate Misbehaviour, which pushes for better working conditions in China, pointed the finger at Foxconn. The group had published a report in early May about the factory and its lack of safety procedures which foreshadowed the accident. Foxconn manufactures many popular electronic devices, including products  such as Apple's popular iPad.

The tragedy happened in the polishing department of Foxconn and involved an explosion of ultra-light dust. Workers complained to SACOM that the ventilation of department is poor. Workers polish the iPad cases to make them shiny. In the process, there is lots of aluminum dust floating in the air. Workers always breathe in aluminum dust even though they put on mask. When workers take off their cotton gloves, their hands are covered with aluminum dust. Regardless the explosion, this is detrimental to the health of workers, SACOM said in a recent blog post. Aluminum dust is flammable under certain conditions and can explode at sufficiently high concentrations.

The advocacy group said the Chengdu factory was built too fast, and the ongoing construction has been hazardous to employees. According to SACOM, construction and production take place side by side, leaving the workers exposed to numerous hazards including dust residue and dangerous materials.

Other than confirming a third death and the cause of the accident from combustible dust, Foxconn has said little about the accident. The company did say it is cooperating fully with all relevant government bodies to carry out a full investigation into the cause.

Meanwhile, Terry Gou, chairman of Foxconn parent Hon Hai, told suppliers the disaster would not delay production of the iPad 2. He also said it would not delay any new products related to the iPad or iPhone set for rollout in the third quarter.

Analysts also said they thought the explosion would do little to affect iPad 2 production. RBC analyst Mike Abramsky, in a note, said Foxconn should be fine if the factory in Shenzhen could handle production of the iPad or the Chengdu factory could be restored quickly.

However, the restoring of the Chengdu factory quickly is unlikely. Hon Hai has already said workshops that handle polishing for electronic parts and products in China, which is where the accident occurred, are closed for inspection.

Foxconn was in the news last year because a number of employees committed suicide, due to the tough working conditions at the plant. The suicides forced the Apple supplier to change its employee relations.

Apple has only made a brief statement on the explosion, expressing its sorrow and saying it is working with Foxconn to understand what happened.

Foxconn did not respond to a request for comment.