WASHINGTON — The Department of Veterans Affairs says investigators have found no proof that delays in care caused any deaths at a VA hospital in Phoenix, deflating an explosive allegation that helped expose a troubled health care system in which veterans waited months for appointments while employees falsified records to cover up the delays.

Revelations that as many as 40 veterans died while awaiting care at the Phoenix VA hospital rocked the agency last spring, bringing to light scheduling problems and allegations of misconduct at other hospitals as well. The scandal led to the resignation of former VA Secretary Eric Shinseki. In July, Congress approved spending an additional $16 billion to help shore up the system.

The VA’s Office of Inspector General has been investigating the delays for months and shared a draft report of its findings with VA officials.

In a written memorandum about the report, VA Secretary Robert A. McDonald said: “It is important to note that while OIG’s case reviews in the report document substantial delays in care, and quality-of-care concerns, OIG was unable to conclusively assert that the absence of timely quality care caused the death of these veterans.”

The inspector general’s final report has not yet been issued. Deputy VA Secretary Sloan Gibson confirmed the findings in an interview with The Associated Press. Gibson, however, stressed that veterans are still waiting too long for care, an issue the agency is working to fix.

“They looked to see if there was any causal relationship associated with the delay in care and the death of these veterans and they were unable to find one. But from my perspective, that don’t make it OK,” Gibson said. “Veterans were waiting too long for care and there were things being done, there were scheduling improprieties happening at Phoenix and frankly at other locations as well. Those are unacceptable.”

In April, Dr. Samuel Foote, who had worked for the Phoenix VA for more than 20 years before retiring in December, brought the allegations to Congress.

Foote accused Arizona VA leaders of collecting bonuses for reducing patient wait times. But, he said, the purported successes resulted from data manipulation rather than improved service. He said up to 40 patients died while awaiting care.