Over the years, Apple has built a loyal following because of its ingenuity and willingness to buck norms. Its customer base tends to be highly educated, concerned about conditions in foreign countries and affluent enough to afford the latest, cool new Apple product – such as an iPad or iPhone.

Yet many of Apple's most devoted customers are angry at the moment, and rightfully so. Last week, the New York Times published a searing expose of worker conditions at Apple subcontractor plants in China, where iPads and other Apple devices are assembled.

Many Americans are oblivious about factory conditions in China, partly because that country makes it hard for workers to report abuses and for outside groups to monitor them. But the Times was able to document an appalling pattern of worker mistreatment by Apple subcontractors at several factories, including ones owned by Foxconn Technology, one of Apple's biggest partners worldwide.

The list of abuses includes workers exposed to poisonous chemicals; workers forced to work excessive overtime seven days a week; workers stuffed into overcrowded dorms and laboring at risk of deadly explosions. Within seven months last year, the Times reports, four people were killed and 77 injured in two explosions, including one at a site where employees polish thousands of iPad cases each day.

As the Times noted, others have documented grim working conditions at factories affiliated with Dell, Hewlett-Packard, IBM, Sony and other tech firms. Apple put itself ahead of many companies by adopting a code of conduct in 2005 that has led the company to audit subcontractors, report problems and reveal plans for preventing violations.

In its latest report, Apple reports: "We have a zero-tolerance policy for underage labor, and we believe our system is the toughest in the electronics industry. In 2011, we broadened our age verification program and saw dramatic improvements in hiring practices by our suppliers."

All that is good, but if you comb through Apple's reports from previous years, you'll find numerous vague references to unnamed suppliers who committed violations. That kind of obfuscation makes it hard for outside groups to verify the company's findings, particularly its claims of improved conditions at certain plants.

Even more troubling is Apple CEO Tim Cook's response to the New York Times story. In an email to employees, Cook didn't dispute any factual findings in the report, but he sounded personally insulted that anyone would question Apple's commitment to worker safety in its supply chain.

"Any suggestion that we don't care is patently false and offensive to us," Cook wrote. "As you know better than anyone, accusations like these are contrary to our values."

What should be really offensive to Cook and Apple is not accusations but reality. All too often, Apple's products are built on the backs of overseas workers who are mistreated, overworked and exposed to dangerous work environments.

Yes, Apple is ahead of many companies in monitoring and correcting problems. But it is also the fastest growing of any tech company. The sheer volume of products it assembles and sells – especially in a country as sprawling and closeted as China – posits questions about whether Apple can track abuses in real time.

On the other hand, Apple is known for achieving the unimaginable and holding itself to higher standards. Any company that can create something as innovative as the iPad should be able to ensure its supply chain protects the environment and human dignity.

There ought to be an app for that.

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