NPR met last week with 25 workers who had been hurt during the incident, which took place at a Pegatron subsidiary's metal casing factory last December. According to Apple, a total of 61 people were hurt as a result of the blast.
Ignition of aluminum dust was found to be the cause of the explosion. The factory had not yet begun operations and was in the midst of trial production when the accident took place.
A worker at the factory, Zhang Qing, said that, on the day of the incident, the plant's managers had told employees to clean up dust because Apple's inspectors were coming through. According to Liu Hengchao, another worker who was injured in the explosion, the inspectors wore white gloves to check for dust.
Workers were not warned not to talk to them, Liu said. They reportedly spent 10 minutes in the area.
He Wenwen told the publication that he was calibrating a machine used for polishing aluminum backings for the iPad 2 later that day when he saw a "fireball" coming toward him.
"I lost consciousness for a few seconds," he said. "Later, when I opened my eyes, I saw dense smoke and fire everywhere. I felt scared, really scared. I could hear people crying and screaming."
The upper half of He's face was burnt by the fireball. Report author Frank Langfitt wrote he looks as if he's "wearing a bright, red mask."
According to He, dust was a problem at the factory despite the fact that each polishing machine had an exhaust. Workers at the plant wore "very thick" face masks, but their nostrils filled with dust when they removed them. "The air in the factory looked a bit like fog," he said.
He said the factory's vacuuming system wasn't very effective and the facility's windows were sealed shut, while Zhang said employees weren't told that the dust could explode. The workers make a base wage of $200 a month and up to $450 with overtime.
Those who had been injured in the blast told Langfitt at the beginning of last week that they had yet to be contacted by Apple about the incident.
"Later â after NPR contacted Apple â other workers said they finally started receiving calls from the company, checking on their injuries and making sure they'd received compensation, which came to about $800 each," the report read.
The Shanghai explosion was preceded by a similar incident at a Foxconn factory in Chengdu, China that resulted in four deaths and 18 injuries.
Foxconn workers file down the Apple logo on an iPad component. | Credit: Almin Karamehmedovic/ABC News
Apple wrote in its 2012 Supplier Responsibility Report that it was "deeply saddened" by both of the accidents. The company said it reached out to the "foremost experts in process safety" immediately after they occurred to understand what happened. Though the causes of both incidents were found to be different, Apple did confirm that combustible dust was involved in both of the explosions.
The iPad maker says it audited all of its suppliers handling aluminum dust and put "stronger precautionary measures" in place before resuming production. New requirements for work places coming in contact with dust include: ventilation requirements with regular testing; comprehensive inspections of ductwork to identify aluminum dust deposits; a ban on high-pressure compressed air for cleaning; a requirement that all vacuums be rated explosive proof and ensuring that type-D fire extinguishers are on hand to deal with metal fires.
Even as Apple has come under fire from mainstream media outlets and non-profit organizations for worker conditions at its suppliers, the company has taken steps to address concerns. Apple announced in January that it had joined the Fair Labor Association. The FLA began inspections of Foxconn last month. However, one non-governmental organization claims to have spoken with factory workers who said that the manufacturer was ready for the inspections and had preemptively covered up any violations.
FLA President Auret van Heerden said after his first visits to Foxconn's facilities that the operation was "first class" and conditions are "way, way above the average of the norm." He did, however, also say that there are still "tons of issues" that need to be addressed.