To understand the breakdowns that led to one of the most tumultuous medical device recalls in generations, the Pittsburgh Post-Gazette and ProPublica spent a year probing what happened inside Philips Respironics after the company first learned that contaminants were turning up in breathing machines designed to save lives.

The news organizations also tracked what has happened since the recall as the company claimed that the devices — including ventilators and continuous positive airway pressure or CPAP machines — were safe despite multiple test reports showing that foam embedded in the devices to reduce noise was breaking down and potentially sending dangerous particles and chemicals into the masks of patients.

Reporters for the two news outlets collaborated with NRC Media in Amsterdam, where Philips’ parent company, Royal Philips, is headquartered, as well as with student journalists from Northwestern University’s Medill Investigative Lab.

Reporters obtained newly unsealed court documents, internal emails, text messages and public records in the United States and other countries to track Philips’ and its parent company’s response to the problem. Those documents included records from four tests conducted by independent labs brought on by Philips that describe the chemicals released by the foam.

The reporting team also drew on thousands of complaint reports spanning 13 years that were submitted to a national repository known as the Manufacturer and User Facility Device Experience database. The records are maintained by the Food and Drug Administration and describe reports of patient deaths and injuries as well as device malfunctions.

To better sort and examine the reports from MAUDE, the team used a proprietary system called Device Events, a search engine developed by former FDA analyst Madris Kinard.

Over the course of months, reporters pulled every report about the recalled machines. More than 100,000 had been filed with Philips or the government since 2010 by patients, doctors and others. (It is possible that some reports were submitted more than once.)

Because the records include the date the company received each complaint, reporters were able to determine how long it took Philips to submit them to the FDA. Under federal law, medical device makers must file a report with the government within five days for the most serious complaints and 30 days for all others.

The reports described thousands of cases of cancer, liver and kidney conditions, respiratory infections and other illnesses among device users. Some users or their family members directly tied those illnesses to the use of recalled machines. Others simply reported illnesses without elaborating.

Philips has said new tests on its DreamStation CPAP show that the machines are “unlikely to result in an appreciable harm to health in patients” and that testing on ventilators is ongoing. The company has also said that it properly responded to complaints about the foam and launched a recall when the problem became clear.

Testing to determine the level of health risk posed by the foam could take years. The FDA has classified the recall as its most serious: one for device defects capable of causing severe injury or death.

The reporting team interviewed more than 200 people in the United States and a dozen other countries, including former Philips employees who described lapses inside the company that allowed problems to go unaddressed for years. Reporters traveled the country to interview doctors, researchers, patients and the family members of those who died, and consulted public health researchers and physicians on risks posed by the devices. Dr. Ronald Chervin, director of the University of Michigan Sleep Disorders Centers, provided guidance on the science behind sleep apnea and CPAPs.

The news organizations have requested dozens of additional documents from the FDA. In April, ProPublica and the Post-Gazette sued the FDA in federal court in New York over the agency’s refusal to expeditiously release the records, which include company test results from the years before the recall. The case is ongoing.