When you go from six active cases of underage labor to 74 in one year, you know something's wrong. That's what Apple discovered after conducting its 2011 audits as part of its annual Supplier Responsibility Report, which was released late Thursday. In the report, Apple once again detailed its audit process and spelled out its findings, conducting a new high of 339 audits across its manufacturing partners. But the huge jump in underage labor wasn't across the board—it was concentrated in a single circuit board manufacturer, which Apple says was willfully conspiring with families to forge age-verification documents.

According to Apple's new report, the company didn't find any cases of underage workers at its final assembly suppliers in 2012, but it plans to continue going deeper into the supply chain to ferret out violators. These suppliers have apparently told Apple that it's the only company performing such audits.

That much is clear when you get to the part of the report where Apple slams Guangdong Real Faith Pingzhou Electronics Co. (also known as "PZ"). The company produces circuit board components "used by many other companies in many industries" and was found to have 74 cases of underage workers as of January 2012. Apple discovered that PZ was working with one of the area's largest labor agencies to actively recruit and work with underage workers to fake the appropriate documents to make them appear older than they actually were.

As a result, Apple terminated its relationship with PZ and reported the labor agency (Shemzen Quanshun Human Resources) to the provincial governments of Shenzen and Henan. "The agency had its business license suspended and was fined. The children were returned to their families, and PZ was required to pay expenses to facilitate their successful return," wrote Apple. "In addition, the company that subcontracted its work to PZ was prompted by our findings to audit its other subcontractors for underage labor violations—proving that one discovery can have far-reaching impact."

Last year, Apple reported that it found only six active and 13 historical cases of underage labor among its suppliers in 2011—down from 91 total cases found in 2010. Because of these discoveries in recent years, Apple has ramped up its education efforts, helping suppliers identify fake IDs and giving suppliers the names of labor agents that "have been associated with the recruitment of underage workers."

When new violations are found, Apple requires its suppliers to return the workers back to a school chosen by the family and finance their education. "In addition, the children must continue to receive income matching what they received when they were employed. We also follow up regularly to ensure that the children remain in school and that the suppliers continue to uphold their financial commitment," wrote Apple in its latest report.

Apple has come under fire in recent years for its suppliers' labor and safety practices after the publication of a 2006 report highlighting poor conditions, followed by another in the New York Times in early 2012. The latter prompted Apple to become the first technology company to join the Fair Labor Association (FLA) in order to check its own reports against independent audits. The FLA's audits began in February of 2012, followed a month later by a report that revealed more than 50 violations of FLA standards and Chinese law, largely related to the way overtime was handled among employees. But as of August, the FLA reported back to say that Apple and Foxconn (in particular) were indeed improving factory conditions and were actually ahead of schedule in implementing the recommendations from the FLA.

"Our verification shows that the necessary changes, including immediate health and safety measures, have been made," FLA CEO Auret van Heerden said in August. "We are satisfied that Apple has done its due diligence thus far to hold Foxconn accountable for complying with the action plan, including the commitment to reform its internship program."

In addition to the underage labor violations at PZ, Apple's report highlighted its efforts to source conflict-free materials for its products, improve worker safety, and increase training to identify safety hazards. Apple also says it interviewed and surveyed 70,000 workers across its four final assembly facilities in order to see what the workers wanted improved the most—the results showed "opportunities for improvement" in social support, quality of sleep and dining, work-supervisor relationships, and counseling services.

"As a result of our worker surveys at all of the facilities in this pilot, suppliers have taken specific actions, such as changing food vendors, tracking cafeteria food purchases to provide feedback to food vendors, evaluating the impact of room-darkening window shades in dormitories, assigning workers to dormitory rooms based on shift times, and changing security providers for increased coverage," wrote Apple.