Found this from an article on BASF paints. Sounds like GM may be using BASF.
General Motors uses eco-friendly water-based “three-wet” paint process for Chevrolet Sonic
For the production of its subcompact Chevrolet Sonic, General Motors brought online a new paint shop at its Orion Assembly Center that features a "three-wet" paint process. The process eliminates the need for a primer bake oven, normally used between the primer and color-coating layers. The Orion Assembly Center allows three layers of paint to be applied one after another while still wet before a single trip though the oven.
This process reduces the paint shop footprint by 10 percent, said GM. It also provides additional floor space and reduces the energy needed to heat and cool these areas.
"Cutting our greenhouse gas emissions and reducing our energy consumption were key to implementing our water-based three-wet paint process," said Mauricio Pincheira, paint manager at Orion. "We want to provide a durable paint that impresses our first-time Sonic customers and maintain the tough environmental standards we have across the company."
Orion's new paint shop was engineered to minimize energy use while reducing solvent emissions. By using the three-wet process, a thin film pretreatment and lean design methods, Orion's paint shop uses 50 percent less process energy per vehicle than the shop it replaced, the car maker said. It is also heated by natural and landfill gas, which results in less emissions than coal-fired boilers.
When full shift production is achieved, Orion's new paint shop will reduce greenhouse gas emissions by approximately 80,000 metric tons per year—equivalent to the annual emissions from 14,000 vehicles—and solvent emissions by approximately 108,000 pounds of solvent per year.
These cost-saving paint process improvements trimmed the manufacturing costs by approximately $40 per vehicle.
Here is the link to the complete article.
http://www.coatingsworld.com/issues/2012-03/view_features/auto-oem-coatings/