Ford is being sued for allegedly rigging at least 500,000 diesel pickup trucks to beat emissions tests, according to Bloomberg. Drivers claim that the F-250 and F-350 Super Duty models emit nitrogen oxide pollutants at 50 times the legal limit — despite Ford marketing the trucks as “the cleanest super diesel ever.”

• Why it matters: Ford joins a list of at least four car companies accused of cheating on U.S. emissions tests. The lawsuit could threaten the automaker's plans to introduce a diesel engine in its smaller F-150 truck, which the company claims could outperform competitors with a fuel economy of 30 mpg.
• What Ford's saying: “All Ford vehicles, including those with diesel engines, comply with all U.S. EPA and CARB emissions regulations. Ford vehicles do not have defeat devices. We will defend ourselves against these baseless claims," Daniel Barbosa, a spokesman for Ford, told Bloomberg in a statement.