There is speculation that the explosion that killed two workers and injured at least 16 others at a Chengdu Foxconn plant last Friday may have been triggered by the ignition of highly flammable dust.

While the cause of the blast is still under investigation, local media have suggested that airborne dust, including magnesium?may have ignited inside a polishing workshop. According to earlier investigations by the Hong Kong-based NGO SACOM, workers had complained of poor ventilation and described the workshop as "hazy" with very high levels of dust in the air. They said that despite wearing protective clothing, their hands and faces were covered with the dust.

Police who were called to the scene after the explosion also said initially it seemed to have been caused by materials within the factory. According to the China Central Television, their preliminary investigation has ruled out sabotage.

The plant where the blast occurred is, according to some reports, a major production base for Apple's IPAD 2, with a capacity of 1.2 million units per month. The plant is said to have been built in just 76 days at a cost of US$2 billion. Another Foxconn plant is still under construction in Chengdu.

Apple was battling hard to keep pace with consumer demand for the IPAD 2 before the explosion. On April 20 Apple's chief operating officer Tim Cook described the shortfall as the "mother of all backlogs." On Friday, industry analyst Mike Abramsky of RBC Capital said the explosion could cost Apple 36 percent of its planned third quarter production.

Some further details have emerged about the blast and its aftermath.

The explosion happened in block A5 of the campus. A worker who was taking an examination in nearby block A7 described how the blast shook the building he was in "just like an earthquake." When workers returned to the plant the following day they were told it was closed until further notice. One worker described the evacuation after the explosion as chaotic.

A nurse said that four injured survivors are being treated on the sixth floor of the Sichuan People's Hospital in Chengdu. Witnesses described scenes of weeping relatives, but attempts to speak to them were blocked by officials from the local government and a number of police, who briefly detained one person. Some Foxconn staff were also present, accompanying the relatives.

Foxconn CEO Terry Gou flew to Chengdu the night of the explosion. Apple spokesman Steve Dowling said the company "is deeply saddened by the tragedy" and "is working closely with Foxconn to understand what caused this terrible event."