For hundreds of companies, Earth Day represents a prime opportunity to get employees pumped up over green -- and, in the process, give a boost to its ongoing sustainability activities.

That's what we heard from dozens of executives when we asked them, "What do you consider your organization's biggest Earth Day successes and failures?"

As we expected, accounts of Earth Day successes far outweighed failures. Yet many shared lessons learned and talked of experiences that were less than glowing. We tip our hat to those brave execs and their candor.

Here are select examples of how companies are engaging employees on this 41st Earth Day:

Kevin Anton, Chief Sustainability Officer, Alcoa

We have learned that we can do more through partnership, and so we have taken our successful "Month of Service" model that last October mobilized 29,000 employees in partnership with 3,000 community organizations, and applied it to our Earth Day celebrations -- working in collaboration with our employees, customers, partners and neighbors around the world. A great example is the e-waste drive we will hold across our U.S. plants over the Earth Day weekend, in collaboration with our new business partner, Electronics Recycling International. By leveraging ERI's recycling infrastructure and making it available in our communities at no cost, we will help provide a much-needed solution to the growing challenge of e-waste.

Terry F. Yosie, President and CEO, World Environment Center

Asked what separates successful employee Earth Day events from those that fail, Yosie said:

The Earth Day events that succeed are those that are specific, participatory, frequently local and therefore authentic. They succeed because they are continuous and result in observable benefits. Those that fail tend to be the celebratory, check-the-box, one-off events that nobody remembers. Or, if people do remember it's because subsequent performance deflated the hype.

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