>> i thought it was important to cover china because apple has all of its products made there. it's caught up in another country's industrial revolution, and a lot of that is out of apple's control. >> four workers died and 77 wounded in explosions at two apple supplier factories caused by careless safety procedures. the solvent used to sparkle apple's touch screens were powerful, but dangerous, causing nerve damage that led to weakness and loss of touch in workers. they complained about low wages and pressure to meet apple's deadlines. in the chinese factories of many tech companies, copper, chromium and others heavy metals saturate the waterways.