Is Coca Cola a more sustainable company than PepsiCo? Which company is greener, Dell or Hewlett Packard? Both UPS and FedEx say they are environmental leaders -- who's right?

Underwriters Laboratories (UL) -- one of the world's oldest and most respected standard-setting organizations -- is going to help settle some of those arguments.

In cooperation with Greener World Media -- publisher of GreenBiz.com, where I'm a senior writer -- UL plans to launch a ratings system for companies by the end of the year. This is a big deal because it could help bring credibility and clarity to the very crowded and confused business of sustainability ratings, rankings and eco-labels.

The news that Greener World Media and UL are working together on a sustainability standard surfaced last week when Marcello Manco, the vice president and general manager of UL Environment, spoke on a panel at the Amsterdam Global Conference on Sustainability and Transparency convened by the Global Reporting Initiative (GRI). At the same time, my friend Joel Makower, the founder of Greener World Media, wrote a detailed blogpost, explaining the origins of the project, which go back to the early 2000s. Joel calls the new venture "LEED for companies," saying:

We've long described this in shorthand as "LEED for Companies" -- that is, a point-based rating system along with good-better-best levels of certification. We have been inspired by the success of the U.S. Green Building Council's LEED green building rating systems, which created definitions of "green building" where there were none. Those ratings systems were critical catalysts in spurring the green-building market. Similarly, we believe this new standard and rating system will help define sustainability at the enterprise level, growing markets for certified companies.

If all goes according to plan, the new ratings system will rise above the crowd because it combines the knowledge and networks of Joel and Rory Bakke, director of sustainability at Greener World Media, who has worked extensively with government purchasing agencies, with the brand and credibility of UL, a global nonprofit that has been ratings products for safety for more than 115 years. UL has 6,700 employees and 65,000 customers around the world.

The UL-Greener World Media product -- it doesn't have a name yet -- could also complement the data on products being compiled by the Sustainability Consortium organized by Walmart, whose members now include retailers Safeway and Best Buy, and consumer products giants P&G, Disney, General Mills, PepsiCo, S.C. Johnson and Unilever. Jon Johnson, co-director of the consortium, was also at the GRI panel, and he said that UL's company ratings would be a good fit with the consortium's product data. "Walmart has reached out to ULE," Johnson said.