Theoretically federal government workers have protections for whistleblowing, but federal workers who try to defend their whistleblowing activities before administrative law judges often find these rights exist on paper only. Private sector whistleblowers have even weaker legal defenses to retaliation. Beyond the risks of job loss and weak legal protection there is also an emotional and mental price to pay for whistleblowing. Do not blow the whistle unless you are prepared to follow through on your charges. It will be difficult to stop in mid-stream and as a general rule it is better to have looked the other way than to have blown the whistle half way.
Most federal agencies have employee hotlines for reporting of fraud, waste or abuse.
Unfortunately, government hotlines have proved neither effective nor safe. Confidentiality is a problem. It's hard to give enough details to support your allegations without identifying yourself. Some hotlines have reported callers' identities to the callers' boss. Corporate voluntary disclosure programs are the private sector equivalent of government hotlines.