Debate over "tsunami" debris on West Coast

It's been nearly ten months since Japan's devastating tsunami.

Much of the debris from the disaster ended up in the Pacific, and ocean currents have been driving some of it toward the United States.

Some scientists say some of the bits and pieces are already washing up on America's West Coast. Among the items they cite: fishing buoys and bottles from Japan that have landed in Oregon, Washington state and Alaska.

Blanket Coverage: Disaster in Japan

But, as CBS News correspondent Lee Cowan reported on "The Early Show" Wednesday, other scientists are questioning whether the debris is from the tsunami at all.

By some estimates, there is upwards of 20-25 million tons of flotsam drifting in the Pacific as a result of the killer waves, spread out over an area roughly the size of the state of California.

Many experts predicted U.S. shores wouldn't start seeing objects arrive until late 2012 or 2013.

The National Oceanic and Atmospheric Administration says there's no definitive proof that the objects were washed out to sea by the tsunami. "Fingerprinting it back is challenging," NOAA's Peter Murphy told CBS News.

Still, a handful of independent researchers claim to have tracked them back to their origins in Japan.

Among them, oceanographer Dr. Curtis Ebbesmeyer, who's been tracking Pacific Ocean currents and debris for 16 years. In the last three months, he told "Early Show" co-anchors Chris Wragge and Erica Hill, he's gotten reports of at least 18 buoys washing up in the three states. He says Japanese fishermen confirmed to him that the buoys here came from there. "We have been seeing these buoys sporadically for years," Ebbesmeyer points out, "but we've never seen them arrive in such numbers all at one time."

"We're at the beginning of the beginning" of debris arrivals, he says.

Ebbesmeyer also cautioned that Pacific waters should be tested for radioactivity from Japan's tsunami-crippled Fukushima nuclear power plant, just as the air has been checked.

To see Cowan's report and the Ebbesmeyer interview, click on the video above.