A video released May 25 by Hong Kong NGO Students & Scholars Against Corporate Misbehavior (SACOM) shows staff at Foxconn's Chengdu plant working amid potentially flammable aluminum dust. An explosion at the plant on May 20 killed three workers and injured fifteen.

Don't Miss: 2 dead, 16 injured in Foxconn plant explosion

The two-minute video, filmed in March, shows six or seven workers responsible for polishing computer cases with aluminum dust on their hair, faces, hands and clothes. The workers said that even wearing two pairs of gloves provides no protection from the dust.

SACOM says the video proves that Foxconn did not provide a safe, well-ventilated environment for its workers.

A report released by SACOM on May 6, two weeks before the explosion, said that workers at the Chengdu plant had already complained to management about the dusty environment.

It is well-known that fine airborne aluminum dust creates a risk of fire and explosion.

The report also mentions a cutting fluid used in the assembly process for which Foxconn had provided no details regarding either its chemical composition or potential health impact.

Foxconn dismissed the May 6 report, saying that it "always guarantees workers have health and safety protections of the highest standard." In hindsight, this may turn out to have been a costly mistake.

A SACOM press release claims that after the explosion last Friday, Foxconn made sure the injured workers were sent to a local hospital and kept victims' relatives under surveillance to prevent information leaking out to the press.

According to Hong Kong China News Agency, a twenty-year-old Foxconn worker, whose surname was Hou, plunged to his death from a dormitory building in Chengdu yesterday.