Federal investigators are examining claims that the Department of Veterans Affairs retaliated against 37 whistleblowers, including workers who tried to report actions relating to the agency’s recent scheduling scandal.

The complaints include allegations that managers demoted, suspended and lowered the performance ratings of employees who tried to expose inappropriate record-keeping practices at VA hospitals, according to the Office of Special Counsel, a federal investigative and prosecutorial agency that protects federal employees from reprisals.

Claims of retaliation against whistleblowers have arisen at 28 VA locations in 18 states and Puerto Rico, OSC said.

“The frequency with which VA employees are filing these complaints is one of the highest levels in the federal government,” said OSC spokesman Nick Schwellenbach.

The complaints involve VA facilities in Arizona, Arkansas, California, Colorado, Delaware, Florida, Georgia, Iowa, Kentucky, Michigan, North Carolina, New York, Pennsylvania, Puerto Rico, South Carolina, Tennessee, Texas, Utah and Wyoming, the OSC said.

VA has agreed to put disciplinary actions against three of the employees on hold while the OSC investigates their claims. The department said in a statement Thursday that it is “committed to whistleblower protection and creating an environment in which employees feel free to voice their concerns without fear of reprisal.”

The American Federation of Government Employees, which represents VA workers, said the OSC announcement underscores concerns that the union has raised for years through congressional testimonies and labor-management forums.

“Employees should not fear for their jobs, their pay or their performance evaluations when it comes to speaking up for the rights of VA patients,” said Alma Lee, president of the AFGE national VA Council. “They are . . . best equipped to recognize when policies, procedures and initiatives are not carried out at the highest level.”

An inspector general’s interim report last week said VA health centers manipulated their records to hide treatment delays, possibly with the intent to improve their performance marks. The OSC said roughly half of the VA complaints were filed before news organizations began widely reporting the problems around late April.

Former VA secretary Eric K. Shinseki resigned last week after the findings were released, and President Obama appointed VA Deputy Secretary Sloan Gibson to head the department on a temporary basis as he identifies a permanent replacement.

Before resigning, Shinseki removed three officials from the Phoenix VA hospital where some of the first of the recent whistleblower allegations emerged. The inspector general’s report largely dealt with inappropriate scheduling practices at that facility, although it said the problems appeared to be systemic throughout VA. Its investigation is continuing.

Sloan said at a news conference Thursday in Phoenix that he would “not tolerate for a minute” any retaliation against workers who report wrongdoing.

“Engaged employees — that’s what you want,” he said. “You want them raising their hand and saying we have a problem.”

According to the OSC, VA proposed a seven-day suspension for one VA employee who communicated concerns about inappropriate scheduling practices and coding procedures to the department’s inspector general. The worker also claims to have been reassigned and given a negative performance evaluation.

Not all of the VA complaints involved concerns about scheduling practices. In one case, an employee reported that a clinic was continuously using patient restraints in violation of department policy.

The OSC has authority to seek relief for federal-employees whistleblowers when they face reprisal. It can also pursue disciplinary actions against managers and officials who retaliate against whistleblowers. The consequences range from reprimands to removals.

Sen. Chuck Grassley (R-Iowa), a longtime advocate for whistleblowers, applauded the OSC for investigating the retaliation complaints.

“Whistleblowers are usually at the heart of exposing a major scandal,” he said in a statement Thursday. “They ought to be celebrated, not punished, for acting in the public interest.”