Elon Musk is endorsing a radical plan for the way California handles Volkswagen’s emissions scandal.
The Tesla Motors (TSLA) CEO, along with 38 executives, environmental group leaders, and investors, lent his name to an open letter addressed to California Air Resources Board (CARB) chairman Mary Nichols.
The plan lets VW off the hook in California to fix cars already on the road in exchange for stricter emissions standards and forces the company to instead make emission-free cars going forward.
In September, the Environmental Protection Agency called out Volkswagen for software, called “defeat devices” that cheated on reporting emissions numbers to meet U.S. laws. The devices were reportedly installed in over 11 million cars around the world.
The letter from Musk and his associates proposes that CARB direct VW to “cure the air, not the cars.” The first two pats of the five-part plan are the most radical:
The third proposed change requires VW to reduce its emissions by 10 times the amount of cheating involved with the diesel fleet. The proposal says this must be achieved in five years.
The letter continues:
The authors claim that simply telling Volkswagen to meet tighter diesel standards in the future “will prove even more fruitless.” It adds, “a giant sum of money will thus be wasted in attempting to fix cars that cannot all be fixed.”
Fortune has reached out to CARB for comment and will update this story if it responds.