Patagonia's founder, Yvon Chouinard, talked about the concept of "sustainability" recently:

Yeah, it's a lot like "gourmet." You get gourmet hamburgers now. It's a watered-down word. There is no sustainability as far as any human, economic endeavor. We're polluters here, and we recognize that. All you can do is work toward minimizing the damage that you do. You'll never be sustainable.

It may be that Chouinard has grown cynical after years of running his outdoor-gear company, but what rational company wouldn't want to tag on "sustainable" to its public relations, even if it runs one of the most unsustainable businesses in the world? So now, just as someone buying eggs has to sort through and make sense of "cage-free," "free-range," "vegetarian," and "organic" varieties, a well-meaning investor has to discern between corporate greenwashing and actual damage-minimizing efforts.

How can an investor get a clearer look through the corporate fog of war to buy into a socially responsible business? Here are a few ways to start.

Rankings
First, to help get a broad collection of potential investments, check out the lists from groups like the Corporate Knights. This company publishes an annual ranking, the Global 100, of companies that score well on several different metrics, including waste, water, and energy productivity, CEO-to-average-worker pay, taxes paid, and safety. Top companies this year included Danish pharmaceutical Novo Nordisk (NYSE: NVO), Norwegian energy producer Statoil (NYSE: STO), and Dutch technology firm ASML Holding (Nasdaq: ASML). The inclusion of an oil company may seem out of place when talking about sustainability, but Corporate Knights designs its survey to be "product- and service-agnostic," in hopes of eliminating any subjective bias.

As Corporate Knights argues: "this approach isn't perfect. It doesn't capture the contamination of ecosystems, land grabs in Africa, underhanded lobbying tactics, or poor treatment of civilians in foreign countries ... but we can always shine a light on those behaving badly in different areas."

Be careful to take note of what metrics the rankings actually measure, and who measures them. Even though it would be easy to take Corporate Knights at its word, it still has a goal of selling data and subscriptions. Use lists like these as a jumping-off point to highlight companies that you might want to research further.

Search the Web
Once you've identified a potential company worth your investment, scour the Web for any potential wrongdoings. Check out Glassdoor.com to see what employees say. Search news sites to find information beyond the press releases posted on an investor-relations website. Chances are that there will be a negative take on a company's policies or past actions, because, as Patagonia leader Chouinard said, you can only minimize the damage that you do. Some companies will take no accountability for the damage, while others will be more in a gray area where you have to decide whether it is enough.

For example, Whole Foods Market (Nasdaq: WFM) provides health care for employees, caps executive pay to 19 times its average worker's compensation, gives 5% of its profits to community and nonprofit organizations each year, and buys renewable-energy credits. But it received flak in the past for not reporting its greenhouse gas emissions.

Fund reports
If you've heard of a mutual fund that carries your values of sustainability, read its quarterly letters and look at what companies it has invested in. With more research resources at its disposal, a mutual fund that you trust can be a good source of information. One such firm I admire is GMO, led by Jeremy Grantham. He has many great quarterly letters to read, in which he has expounded that "you can have 'growth' -- for now -- or you can have 'sustainable' forever, but not both." And while not claiming to be a "sustainable" fund, as you'll see in its largest holdings, the firm's philosophy resonates with long-term investors. Currently, some of GMO's top holdings include Johnson & Johnson (NYSE: JNJ), Microsoft, and Philip Morris International. Of course, you should use these holdings as a start, as the fund could have bought in or sold out anytime in between disclosures.

For more of a traditionally "sustainable" fund to watch, take a look at Generation Investment Management, which was co-founded by former Vice President Al Gore.

Damage-minimizing portfolios
While companies continue to water down the meaning of sustainability, both investors and truly committed firms will have to find easier ways to communicate and cut through the public-relations noise. These are just a few ways to start, and I've left off other means like researching a founder's beliefs, looking at resource certifications, and actually talking to employees. The big takeaway is to take any sustainable claims with caution and follow up with your own legwork.

For more ideas, check out how socially responsible Fool Alyce Lomax invests her portfolio. In addition, read our free report that teaches you the basics of building wealth and reveals "3 Stocks That Will Help You Retire Rich."