The Department of Veterans Affairs regularly uses a “harmless error” defense to deny that serious problems with VA medical care ranging from unsanitary work practices to treatment delays could affect patients, according to a federal watchdog agency.

In a letter to President Obama and Congress on Monday, the Office of Special Counsel detailed 10 cases nationwide in which the VA and its Office of Medical Inspector acknowledged treatment issues but refused to acknowledge impacts on veterans.

The OSC, which investigates whistleblower complaints and protects federal employees from retaliation, substantiated a long list of problems, from high levels of Legionella bacteria at a Grand Junction, Colo. clinic to a psychiatric patient who waited eight years for his first evaluation after being admitted to a VA mental-health facility in Brockton, Mass.

OSC said it is reviewing more than 50 complaints from VA workers who allege that inappropriate practices harmed patient safety or health. The watchdog agency said it has referred 29 of those cases to the VA for further investigation.

“These cases are part of a troubling pattern of deficient patient care at VA facilities nationwide, and the continued resistance by the VA, and [Office of Medical Inspector] in most cases, to recognize and address the impact on the health and safety of veterans,” U.S. Special Counsel Carolyn Lerner said in the letter.

Lerner added that the harmless-error defense has “prevented the VA from acknowledging the severity of systemic problems and from taking the necessary steps to provide quality care to veterans.” She said that “veterans’ health and safety has been unnecessarily put at risk” because of the issue.

Monday’s letter follows recent revelations about systemic falsification of scheduling records to hide treatment delays at VA medical centers across the country.

The OSC substantiated claims of related scheduling schemes at VA clinics in Jackson, Miss. and Fort Collins, Colo. The watchdog said it is examining reports that two Fort Collins schedulers were removed from their positions for refusing to “zero out” wait times to cover up delays.

Much of the OSC letter focused on the Jackson hospital, where the agency substantiated claims of improper credentialing, unlawful narcotic prescriptions, noncompliant pharmacy equipment used for chemotherapy drugs and unsterile medical devices.

“Despite confirming the problems in each of these (and other) patient-care areas, the VA refused to acknowledge any impact on the health and safety of veterans seeking care,” Lerner said.

In response to the findings, VFW spokesman Joe Davis said: “There is no such thing as ‘harmless errors’ when you deal with people’s lives.”

Lerner recommend that the VA designate a high-level official to assess the watchdog agency’s conclusions, consider corrective and disciplinary actions and determine whether the substantiated claims indicate systemic problems.

Acting VA Secretary Sloan Gibson, who took over as head of the agency after the resignation of former VA chief Eric Shinseki last month, said he accepts the OSC recommendations and directed a comprehensive review of the Office of Medical Inspector’s operations, to be completed in two weeks.

“I am deeply disappointed not only in the substantiation of allegations raised by whistleblowers, but also in the failures within VA to take whistleblower complaints seriously,” Gibson said in a statement.

Gibson added that he reminded all VA employees that they must “protect whistleblowers and create workplace environments that enable full participation,” saying retaliation and intimidation of workers who expose problems is “absolutely unacceptable.”

House Veterans Affairs Committee Chairman Jeff Miller (R-Fla.) said in response to the OSC findings that the VA has inhabited a “fantasy land” with its stance toward patient-care concerns.

“It’s impossible to solve problems by whitewashing them or denying they exist,” Miller said in a statement. “This is a lesson the VA should have already learned as part of its delays-in-care crisis, but President Obama needs to help reiterate it to each and every VA employee to ensure the department’s focus is on pinpointing and solving problems, rather than downplaying them.”

Senate Veterans Affairs Committee Chairman Bernie Sanders (I-Vt.) said in a statement on Monday that “legitimate concerns must not be covered up or papered over by administrators” at the VA. He noted that lawmakers on Tuesday are scheduled to begin finalizing legislation to address some of the VA’s recent problems.

“A conference committee will meet tomorrow to try to iron out differences on legislation passed by the Senate and the House that I hope will significantly improve the quality and timeliness of care,” Sanders said.

The Senate this month approved a Sanders-sponsored bill that would allow the VA to address treatment delays by contracting more with private medical centers and shifting $500 million from its budget toward hiring medical staff. The measure would also give the VA secretary greater power to fire or demote senior executives for poor performance.

The House has passed stand-alone bills that would have similar effects, but the conference committee must come up with final legislation that combines the proposals and works out their differences.