Washington (CNN) -- The chairman of the Senate Armed Services Committee plans to unleash a withering attack Wednesday on private contractors working for the company formerly known as Blackwater in Afghanistan, accusing them of flouting regulations and endangering the U.S. mission.





Key to beating the Taliban in Afghanistan will be the ability of U.S. forces to win support from the Afghan people, many of whom do not distinguish between U.S. contractors and the U.S. military, Sen. Carl Levin will say, according to an advance text of his remarks.





"If we are going to win that struggle, we need to know that our contractor personnel are adequately screened, supervised and held accountable -- because in the end, the Afghan people will hold us responsible for their actions," the Michigan Democrat will say.





"If we don't fix the problems of oversight and make sure contractors like Blackwater play by the rules and live up to their commitments -- we'll be doing a disservice to our troops by making their already difficult and dangerous job even more so."





See agenda of 9:30 a.m. Wednesday hearing





Though more than 100,000 contractors operate for a variety of contractors in Afghanistan, Levin singled out Paravant, a company that had "no meaningful distinction" from the company formerly known as Blackwater, which is currently known as Xe Services, he said in the advance text.





Shooting at Camp Darulaman





Levin cited a December 9, 2008, shooting at the U.S. military's range at Camp Darulaman during which a Paravant program manager carrying an AK-47 got on the back of a moving car, then shot and wounded a Paravant trainer on his team when the car hit a bump, Levin said.





Though the program manager lost his job, the others on his team who allowed his activities did not, he said.





Combined Security Transition Command - Afghanistan, a multinational military formation that trains the Afghan National Army, did not appear to have investigated the incident, he said.





Had it done so, the U.S. Army "would have seen that Paravant personnel were using weapons improperly and unsafely, with inadequate supervision, and that they were carrying weapons that they weren't even supposed to have," according to Levin.





Two civilians killed





He also cited a widely reported May 5, 2009, incident in which two Paravant personnel fired their weapons, killing two Afghan civilians and wounding a third. The two men have been charged with murder in the shootings.





An Army investigation appeared to find that the contract personnel had "violated alcohol consumption policies, were not authorized to possess weapons, violated use-of-force rules and violated movement-control policies," said Levin, who cited as his source the man who then led the Combined Security Transition Command -Afghanistan.





Paravant's contract required it to "ensure that its personnel ... behave at all times in accordance with the highest professional and ethical standards," Levin said.





Records for the two men responsible for the May 5 shooting show the company failed to properly vet them, Levin said.





One man's military record "apparently included assault, insubordinate conduct, absence without leave, failure to obey order or regulation, larceny and wrongful appropriation," he said. And his criminal record showed convictions for reckless driving, disturbing the peace, assault and battery, driving while intoxicated, resisting arrest and trespassing.





The other man was cited in a news report for having been discharged from the U.S. military after being absent without leave for 22 days and testing positive for cocaine, Levin said.





Other Paravant personnel were fired for alcohol use and drug use, he said.





Company looks forward to testifying





In a written statement, a spokesman for Xe Services said the company is looking forward to testifying Wednesday.





"Xe's new management was taking steps to address shortcomings in the Paravant program when the tragic May 5 incident occurred," said Mark Corallo of Corallo Comstock Communications. "One of those shortcomings discovered was that the former management of Paravant had provided weapons to personnel for personal protection without first obtaining the proper authorization from DoD.





"Though Raytheon, the prime contractor, and the DoD customer were both
Who is the chairman? How many private contractors work for Blackwater?
Sen. Carl Levin 100,000
question: Who is the chairman?, answer: Sen. Carl Levin | question: How many private contractors work for Blackwater?, answer: 100,000