Ten months after a tsunami devastated parts of Japan, some of the island nation’s debris has washed up on North American shores, according to news reports.

On Vancouver Island, B.C., The Sun newspaper reported that wreckage from Japan began appearing this month. "In or around Dec. 5th the first item or two of some consequence was found," Tofino Mayor Perry Schmunk told the newspaper. "Some lumber came ashore that had Japanese export stamps on it."

Two weeks ago, CNN affiliate KIRO in Seattle showed video footage of what it said was debris from the March 11 tsunami - at least 10 Japanese buoys - on the Washington coast. “That’s about as good as the evidence gets for first arrivals,” retired oceanographer Curtis Ebbesmeyer told KIRO.

More reports of mundane Japanese items - such as bottles and toothbrushes - popping up along North American shores are beginning to emerge.

But that’s just the beginning, experts say.

Physicist Michio Kaku said Thursday that it is vital to understand the sheer size of the Japanese debris field in the Pacific Ocean.

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“First, you have to understand the size and scope of this problem. The debris field from this Japanese tragedy is the size of the state of California,” he said.

The recent findings have not come without debate. The National Oceanic and Atmospheric Administration has denied that the debris can be definitively traced back to the tsunami. "Fingerprinting it back is challenging," NOAA's Peter Jackson told CBS News.

But scattered news reports along the Pacific coast paint a different picture: A man found seven white Styrofoam floats shaped like 55-gallon drums in late September, Alaskan news station KTVA reported recently. The man sent photos of the floats to Ebbesmeyer, who said they were linked with oyster farms in Japan.

Hawaiian researchers are preparing studies that may allow more precise forecasts of the debris field spawned from the March 11 tsunami.

Tsunami debris in Hawaii at 2013? Maybe sooner

While the significance of the floating mass has yet to be fully understood by scientists, there is concern about what hazardous materials are out there.

Radioactivity will be of minimal concern despite the damage at the Fukushima Daiichi nuclear plant – “The debris is not that radioactive,” Kaku said - but the worst-case scenario could mean large boats and unmanageable clots of trash ramming into sensitive areas such as coral reefs or blocking navigation routes into Hawaii and along the U.S. West Coast.

"The first problem is hazardous materials, then we have toxic chemicals and also human body parts, sad to say," Kaku said Thursday. "Realize that over 3,700 Japanese are still unaccounted for and are expected to have been washed into the Pacific Ocean."