A new explosive has begun to replace 19th century black powder as Alaska Natives seek more humane weaponry in the traditional hunt for bowhead whales.

"It's a lot safer," said Eugene Brower, a Barrow whaling captain who chairs the Alaska Eskimo Whaling Commission's weapons improvement program.

Brower trains Native whaling captains to handle a harpoon-launched grenade loaded with penthrite, a World War I-era explosive used in demolition.

"They love it," Brower said of the whaling captains. "It's four times the strength of black powder. With black powder, the meat has a gas taste."

Alaska's whaling commission began researching new weaponry when the 66-member International Whaling Commission mandated two decades ago that more humane methods be developed.

The commission wanted to reduce the number of whales lost at sea after being hit by explosives and to decrease the time it took for a whale to die after being struck.

Researchers in 1995 reported Alaska bowhead whales lived about 60 minutes after being hit with black-powder grenades; bowheads hit with penthrite grenades survived only about 15 minutes.

"We have a position that no whaling is humane," said Patricia Forkhan, president of Humane Society International. "But Alaska Natives have worked a long time toward a more humane and efficient hunt, and we've been supportive. If penthrite is working, that's good."

Penthrite, short for pentaerythritol tetranitrate, is used in blasting caps and easily detonates. Once the grenade penetrates the whale's skin and explodes, it produces a concussion that lethally shocks the central nervous system.

Brad Smith, an Anchorage biologist with the National Marine Fisheries Service, said penthrite has a high probability of killing even if the grenade does not strike a vital area.

Black powder, which dates to 19th-century Yankee whaling, is a slow-burning explosive that generally kills by causing hemorrhage. If a whale is struck near a vital organ, death can be swift. But multiple strikes sometimes are needed, endangering crews in traditional, wooden-ribbed boats as a bowhead thrashes in icy seas.

By virtually assuring a swift death, penthrite grenades have increased the chance that a whale will pulled in safely. Bowheads measure 50 feet or more and can weigh up to 110 tons.

About 30 of Alaska's 160 Native whaling captains have completed a training and certification program offered by the Alaska whaling commission and taught by Brower.

Alaska whalers take bowheads from protected stocks that number about 10,000 animals and range in the Bering, Chukchi and Beaufort seas. The hunt is overseen by the International Whaling Commission and managed by the Alaska commission for its 10 member villages.