Though the "Greenlist" logo is designed to look like a third-party classification, it is in fact SC Johnson's own labeling. There's currently a law suit in California based on this.
They basically use this logo to denote products in which the ingredients have been improved in any capacity. For example approximately 20% of the ingredients that used to be rated as "acceptable" by Greelist standards have been replaced with ones rated "better" or "best". However this still leaves over 50% of the ingredients "acceptable" or not rated at all.
In their own words:
A Look Inside Our Process
Since developing our Greenlist™ process in 2001, SC Johnson has rated more than 95% of the raw materials we use. This means we aim to make the best ingredient choices to protect people and the planet, while maintaining product performance. Through reformulations over the last five years we've eliminated 48 million pounds of VOCs from of our products. And, we're continually seeking better ingredient options. This is one way we're working to lessen our environmental impact and do what's right for the families who use our products.