Some critics say Earth Day, which celebrated its 33rd birthday yesterday, has morphed from a nationwide rally to a chance for corporations of questionable environmental repute to engage in greenwashing. In Houston, Tex., for example, Earth Day activities this year were paid for by Waste Management, which owns 293 landfills and has been held responsible for many hazardous-waste sites. In Tucson, Ariz., Earth Day 2003 was sponsored by Raytheon Missile Systems for the ninth consecutive year; other sponsors included the local electric company and Home Depot. “Waste Management sponsoring Earth Day is similar to Enron sponsoring a seminar on corporate responsibility,” said John Stauber, author of Toxic Sludge is Good for You and an expert on greenwashing by pollutocrats. But others, including Earth Day founder Gaylord Nelson, say the eagerness of corporations to participate proves that the event has been a success.