ANCHORAGE, Alaska - Eskimo whale hunters are switching from 19th-century black powder to an explosive considered more humane. During a traditional bowhead whale hunt, a hunter in a wooden-ribbed boat hurls a harpoon with a black-powder grenade attached to it. The grenade penetrates near the whale's blow hole and explodes, killing the animal. The Alaska Eskimo Whaling Commission began researching new weaponry after an international whaling agency two decades ago ordered that more humane methods be developed for killing bowheads. The answer was penthrite, a World War I-era explosive used in demolition that experts say kills more quickly, does not spoil the taste of the meat, and is safer for harpooners, too. Eugene Brower, a Barrow whaling captain who is chairman of the Alaska Eskimo Whaling Commission's weapons improvement program, has started training Alaska Natives to use the new grenade. He said captains from the villages of Kaktovik, Nuiqisit and Barrow have converted to penthrite for the spring and fall hunts. "They love it," he said. "It's four times the strength of black powder. With black powder, the meat has a gas taste." Penthrite kills by causing an explosion that shocks the whale's central nervous system. Black powder, which was used by Yankee whalers in the 1800s, generally kills by causing bleeding. Also, it sometimes takes multiple strikes with black powder to kill a whale, during which the hunters in their wooden boats are in danger from the thrashing bowhead, a species that can measure 50 feet or more and weigh up to 100 tons. Researchers say that black powder generally takes 60 minutes to kill a bowhead whale, while penthrite takes only about 15 minutes. The search for more humane weaponry led the Alaska commission to a Norwegian veterinarian who had produced a cannon-fired penthrite grenade for whalers in Japan and Norway. The National Marine Fisheries Service and the National Oceanic and Atmospheric Agency contributed funding for the necessary research and testing. Patricia Forkhan, president of Humane Society International, said her group maintains that no whaling is humane. "But Alaska Natives have worked a long time toward a more humane and efficient hunt, and we've been supportive," she said. "If penthrite is working, that's good." Alaska Natives have been allowed to hunt whales for subsistence since 1977 under an international agreement.