At age 41, Earth Day is decidedly middle age, and while for some companies, it is a fully-functioning adult, for others it is still in its infancy.

How do Earth Day events at both learning and leadership companies compare, and do they evolve? We asked GreenBiz Executive Network members and other companies -- both newbies and veterans -- to share their thoughts.

Let's begin with the newcomers -- those who have celebrated Earth Day for less than three years. We wanted to know what prompted the start of observations and how have employees received it. Here is what three told us:

Nicole Peill-Moelter, Director of Environmental Sustainability, Akamai

Akamai’s Earth Day observation began in 2009, the year after Akamai formally established its environmental sustainability program. The first year saw broad and enthusiastic participation from many of our offices around the world. Activities, organized by volunteers, focused on sustainability topics such as renewable energy, home energy audits, recycling, electric vehicles, sustainable consumer products, sustainable pot-lucks, and a collage contest. The energy to organize these events has waned significantly since then despite a continued level of interest in our sustainability program.

Sometimes I question whether we are overstepping our bounds when we go beyond educating employees about our sustainability mission and progress, promoting sustainable behavior outside the workplace. We don’t do this in any other area except perhaps encouraging volunteerism to promote corporate citizenship in our communities. So is employee engagement around personal sustainability a new paradigm? A new way of looking at engaging our employees to promote efficiency and innovation in our business as well as extending beyond the workplace to foster a sustainable corporate family in our communities? Is this what environmentally-enlightened new hires are expecting in an employer? Or will it be seen as big brother-ism?

Mary Joann "Majo" Thurman, Director Environmental, Health & Safety, Rockwell Automation

Our new company mission statement, which includes sustainability, prompted the change. A number of sites have been conducting local activities for years that had been driven by a few individuals locally and reported through our EHS newsletter. 2010 was the first year we had a coordinated effort driven from internal communications, of which EHS is one member of a larger team. We received a positive response. We are hoping for more involvement and visibility this year.

Gerri Walsh, Director of Sustainability, Ball Corporation

This is the third year we’ve held this type of event (an Earth Day Sustainability Fair) and we get great feedback from our employees. Prior to this we’ve had quizzes and done mostly internal stuff -- three years ago was the first time we brought in outside vendors.