About 20% of Volkswagen’s vehicle sales are diesel engines. The automaker said in a statement that it’s cooperating with investigators. Owners of those cars are not in any danger and can drive in total safety. However, Volkswagen will be forced to recall all vehicles and to fix the problem for free. “We intend to hold Volkswagen responsible,” Cynthia Giles, assistant administrator for EPA’s Office of Enforcement and Compliance Assurance, told to the media. The state of California has issued a separate notice of violation to the company. EPA and California regulators discovered the device after researchers at West Virginia University and the International Council on Clean Transportation “raised questions about emissions levels” in Volkswagen cars.