California environmental regulators have rejected a proposal by Volkswagen to recall thousands of its diesel vehicles.
The state Air Resources Board had demanded a recall plan in September, after Volkswagen admitted to installing software that can defeat emissions tests.
On the road, the cars can emit up to 40 times the federal limit for nitrogen oxide.
Dave Clegern of the Air Resources Board says VW has not shown it can fix the cars fast enough, without compromising safety or performance.
"Basically, what happened is they designed these vehicles in a way around these defeat devices, so they have to figure out at that point how they’re going to undo that," says Clegern.
Clegern says if that can’t be done, VW may have to buy back its vehicles.
Regulators estimate Volkswagen sold 76,000 small diesel cars in California with the defeat devices and more than a half-million nationwide. Federal and state regulators have separately demanded recall plans for another 80,000 larger diesel vehicles from the Volkswagen Group--including Audis and Porsches--for containing other emissions defeat devices.
The U.S. EPA is suing the carmakers.