Protesters today bearing a petition of 250,000 signatures prepared to march on Apple retail stores in pursuit of a commitment by the iPhone maker to "clean up its supply chain."

Taren Stinebrickner-Kauffman, executive director of SumOfUs, reached by phone was at Apple's Washington, D.C., Georgetown retail location this morning, preparing to deliver the petition to that store. She said the signatures were collected from all around the world by social change organizations and

"What we're asking for is for Apple to clean up its supply chain and improve worker conditions in time to make the iPhone 5 its first ethically produced product," Stinebrickner-Kauffman said, citing reports that the next iPhone will be released sometime later this year.

She said notable Apple supplier Foxconn, which has been dogged by reports of worker suicides and poor factory conditions, is a big part of the problem, but she added that the company is not alone in its shortcomings.

Concern over Apple's manufacturing relationships was stoked by an in-depth Jan. 25 article published in The New York Times that detailed the reality of working in one of Apple's partner Chinese manufacturing facilities.

Apple CEO Tim Cook went so far as to send a widely printed email to employees following the release of The Times article.

"Unfortunately, some people are questioning Apple's values today, and I'd like to address this with you directly," Cook wrote. "We care about every worker in our worldwide supply chain. Any accident is deeply troubling, and any issue with working conditions is cause for concern. Any suggestion that we don't care is patently false and offensive to us."

The Times piece also talked to some former Apple executives who described an unresolved tension within the company between improving conditions within factories and maintaining profits related to delivering products in a timely and cost-effective manner.

Stinebrickner-Kauffman said that the petition's demands are not unreasonable.

"Apple is one of the most competent and creative companies in the world, and it's got the slogan 'Think Different,' and it's time to think different about their supply chain," she said, adding that the delivery of petitions is just the first step in a long-term campaign aimed at prompting Apple to clean up its act.

Volunteers of and will be delivering copies of the petition to Apple retail stores around the globe, including an Apple headquarters in India.

"This is not rocket science to treat your workers with dignity and let them have safe working conditions and pay them a living wage," Stinebrickner-Kauffman said. "It will take some work on Apple's part, but we know they can do it if they put their minds to it."

Apple could not be reached for comment prior to press time.