A dangerous hole could develop in Earth's ozone layer at the North Pole similar to a disturbance found over the South Pole, a U.S. research expedition reported Friday.

Their preliminary findings differ from claims made earlier this week by Canadian scientists who said a serious ozone depletion already exists. The team of U.S. experts did not discount those findings but insisted more time was needed to reach such a conclusion."The atmosphere is primed for destruction of ozone," said Robert Watson, a scientist with the National Aeronautics and Space Administration, but he added, "There's no large ozone hole in the Arctic."

The ozone layer protects Earth from the sun's ultraviolet radiation and destruction of this protective layer will increase the incidence of skin cancer, eye damage and damage to crops.

In 1985, a hole in the ozone layer was detected over Antarctica, and scientists blamed it primarily on chlorofluorocarbons released by industrial refrigerants and solvents. CFCs were also once commonly used as propellents in household aerosol sprays.

For almost 20 years there has been a gradual decline in the amount of ozone in the Arctic, Watson said.

The American expedition, using a high flying, modified U2 spy plane and a DC-8 flying laboratory that carried 30-40 scientists, was stationed in Stavanger, Norway, from Jan. 1 to Feb. 15 and flew numerous missions over the North Pole.

The scientists tracked clouds of ice crystals, suspected in the chemical reaction that caused the Antarctic ozone hole. They also gathered volumes of other atmospheric and meteorological data.

They were supported by an international team of scientists using weather balloons to make readings from other parts of Norway, Greenland, the Soviet Union and the Shetland Islands northeast of Scotland.

"What we're saying is man-made compounds have been transformed into chemicals that can destroy the ozone," Watson said.

The U.S. scientific team did not discount the recent Canadian findings, but said the American efforts were more "conservative" and used more in-depth equipment and research techniques.

Dr. Wayne Evans, the chief of the experimental studies division of the government department Environment Canada, said Wednesday there was a "crater" of ozone depletion over Scandinavia during the first week of February, larger and deeper than a crater discovered in 1986.

The 12-member Canadian research team, which relied primarily on recording made by weather balloons, was stationed at Alert in Canada's remote Northwest Territories.

Joseph Goffman, a spokesman for the Environmental Defense Fund, offered an explanation for why the Canadian scientists may have painted a more desperate picture of the Arctic ozone situation.

"The Canadians may feel they have more at stake if there were an Arctic ozone hole because it could really directly affect the Canadian territory and population," he said.

Under an international treaty called the Montreal protocol, more than 30 countries have agreed to reduce CFC use by 50 percent by 1998, but the Environmental Protection Agency wants a complete ban.