CHICAGO (CBS) – A former U.S. Marine, who was left in a wheelchair following his service in Afghanistan, is filing a lawsuit alleging he was injured and left soaked in his own urine after he was mistreated by airline and airport workers at O’Hare International Airport nearly two years ago.

WBBM Newsradio’s Terry Keshner reports former Marine Sgt. Joseph Smith was wounded in Afghanistan in 2004, and confined to a wheelchair.

Smith is suing Air Serv Corporation and United Airlines for $300,000 in damages, claiming an Air Serv employee carelessly dumped him out of his wheelchair at O’Hare in November 2010, after ignoring warnings a wheel had become stuck.

LISTEN: WBBM Newsradio’s Terry Keshner Reports

At the time, Smith was traveling as part of a Paralympic shooting team, and trying to catch a connecting flight at O’Hare when the worker tipped his chair over while boarding the plane.

“I flew out of my chair, hit my head on the left side of my head. … I landed on my head,” Smith said.

He suffered a concussion, and said he was denied an aisle seat on his United Airlines flight, and was forced to drag himself to his seat without help. His catheter bag spilled in the process, soaking him with urine.

His attorney, Alex Hattimer, said, “the catheter bag ruptures, he ends up with urine spilled all over him. He drags his urine-covered, limb body down the aisle.”

Smith said the lawsuit is about dignity, more than money.

“Apparently some people out there, they just don’t get it. So, I want to make sure this never happens to someone else,” he said. “I just want people out there to know that … people with disabilities, we’re not invisible. We’re people, too.”

Calls to Air Serv and United were not immediately returned.