Family members and people who lost loved ones due to accidents caused by a defective ignition switch in General Motors Co. cars, attend a U.S. House subcommittee hearing in Washington, D.C., June 18, 2014. Pete Marovich/Bloomberg via Getty Images

General Motors Co should pay for concealing an ignition switch defect from its customers that has been linked to nearly 400 injuries and deaths, a lawyer for an Oklahoma man injured in a car crash told a Manhattan jury on Tuesday.

"This case is not just about an accident that occurred in Oklahoma in 2014," said Robert Hilliard, who is representing plaintiff Robert Scheuer. "This is about the conduct of a company over a period of time that spanned more than a decade."

Key GM employees knew about the problem for more than 10 years, said Hilliard, adding that evidence would show the automaker's "cover-up" of a dangerous safety flaw.

GM's failure to conduct a safety recall until 2014 created an "ocean of consequences" for Scheuer and other customers, Hilliard said.

His comments came in opening statements in the first trial since GM's recall of 2.6 million vehicles, including Scheuer's 2003 Saturn Ion, over an ignition switch that could inadvertently slip to an "off" or "accessory" position while the car was in motion, stalling engines and disabling critical systems like air bags.

Scheuer's case, in which he is seeking unspecified compensatory damages as well as punitive damages, is the first of six that have been selected to serve as "bellwether," or test, trials in federal litigation over the switch.

Verdicts in the bellwether trials are not binding on the other suits, but they provide both sides insights about the value of each claim. The switch has already been linked to 124 deaths and 275 injuries.

GM has already agreed to pay roughly $2 billion to resolve legal claims and probes in connection with the switch problem, which thrust the company into the hot seat with Congress, regulators, prosecutors and the public two years ago.

Despite following GM's instructions to remove all but a single key from his key ring, the switch slipped to off during a May 2014 accident in which Scheuer's car was run off the highway, flying through the air before crashing into the ground and several trees, Hilliard said. The air bags failed to deploy and protect Scheuer, who said he suffered neck and back injuries.

While acknowledging "mistakes and errors in judgment made by GM employees" over the switch, GM's lawyer, Mike Brock, said the switch was not to blame for Scheuer's injuries.

The Ion's air bags were not designed to go off under the circumstances of Scheuer's accident, Brock said, and the apparent functionality of the car's steering and brake systems raised doubts about whether the switch had actually rotated off. He also said Scheuer had a history of back problems, questioning the severity of Scheuer’s crash injuries.

There are several hundred lawsuits remaining on behalf of individuals injured or killed in crashes blamed on the switch as well as customers who say their vehicles lost value as a result of the recalls.

(Reporting by Jessica Dye; Editing by Alexia Garamfalvi and Tom Brown)