Disturbing reports continue to surface regarding defective Takata airbags found in more than 20 million U.S. autos and blamed for at least 10 traffic deaths. Some of the latest developments include disclosures that Takata’s own engineers altered data discarded evidence of safety problems as much as 16 years before the safety concerns and injury reports surfaced.

Writes the NY Times: Takata did not report the failures to Honda, according to court documents. Instead, it manipulated data to hide results that showed the propellant could combust violently, causing its casing — called an inflator — to overpressurize and rupture, according to the documents. In several instances, “pressure vessel failures,” or airbag ruptures, were reported to Honda as normal airbag deployments, the documents said.

To date, Takata has sold as many as 54 million potentially defective airbag inflators in the U.S. Safety problems, which cause Takata airbags to overpressurize and explode when they deploy, have prompted 14 automakers to recall 28 million inflators in 24 million U.S. vehicles.

Former NHTA safety expert Allan Kam called the latest revelations by Takata “deplorable.” Meanwhile, safety advocates like Consumers for Auto Reliability founder Rosemary Shahan said they are concerned about the cover-up. “It’s bad enough to have a faulty product, it’s even worse to cover it up,” she told the New York Times.