THE newest superhero on the television block has sky-blue skin, grass-green hair, and earth-brown eyes.In its first season battling the "looting and polluting eco-villains" of our time, "Captain Planet and the Planeteers" has become the most-watched syndicated children's program. The animated series also came in first place on the list of the top 10 most-biased television shows published by the Media Research Center, an organization that monitors liberal bias in the media. "Captain Planet and the Planeteers" is the brainchild of Ted Turner, founder of Turner Broadcasting System. The cartoon features five young people from around the world - North and South America, Asia, Africa, and the Soviet Union - who help Captain Planet fight environmental destruction. Gaia, the spirit of Earth, gives the Planeteers magic rings that allow each of them to control an element of nature. When such evil characters as Looten Plunder, Hoggish Greedly, and Sly Sludge become too much for the Planeteers to handle, they combine their powers to summon Captain Planet. Embedded in each episode is a message of environmental activism. "Captain Planet is a metaphor for teamwork and global cooperation," says Barbara Y. E. Pyle, executive producer of the program. A "Planeteer Alert" at the conclusion of each episode tells viewers what they can do to help save the environment - turn off unnecessary lights, recycle newspapers, carpool, or ride a bike. "Saving our planet is the thing to do," goes the rap-theme song. And Captain Planet's departing words sum up his message: "The power is yours." Celebrity voices make some of the characters eerily familiar. Whoopi Goldberg is Gaia and Ed Asner speaks for Hoggish Greedly. Other familiar voices come from Sting, Martin Sheen, and James Coburn. L. Brent Bozell III, chairman of the Media Research Center, has pointed out that all of the well-known voices are provided by politically liberal celebrities. He charges "Captain Planet and the Planeteers" with being anti-business and promoting "fiction as fact, seeking to scare children into political activism." "I don't think 'Captain Planet' is scary," responds Ms. Pyle. "It's empowering, it shows kids that every action counts. I don't consider the environmental issue left wing or right wing, I consider it bipartisan." Pyle admits that turning complex environmental issues into entertaining cartoons isn't easy. "How do you make global climate change fun?" she asks. Mr. Bozell has criticized past episodes as featuring "radical slants on disproven theories such as overpopulation and acid rain." "The global population problem is the most difficult one to deal with," acknowledges Pyle. "But if you can teach kids what exponential growth is, they can draw their own conclusions. You basically make it broad and general enough that you're not pointing a finger at any one thing." The action-adventure cartoon format automatically means both exaggeration and simplification, she points out. Bozell and others have noted that the Planeteer from North America is the most brash and uninformed of the group, while the Soviet Planeteer is the most cerebral. "Captain Planet and the Planeteers" is now seen in more than 80 countries around the world. "Our intention was to make a cartoon that was cross-cultural and cross-generational," Pyle says. When the second season begins in September, Captain Planet and his five human helpers will tackle such issues as endangered species, alternative energy sources, homelessness, drug abuse, and international environmental cooper- ation. The growing popularity of an environmental superhero introduces uncharted dilemmas in the area of product licensing. All toys and other uses of Captain Planet's image are required to be environmentally safe. No single-use items such as paper plates or cups are allowed. "Captain Planet couldn't be out there in the marketplace saying something different than he was saying on television to kids," Pyle says.