Oxygen levels in Hood Canal are dropping into the danger zone, as researchers observe a condition they have never seen before.

Hood Canal never bounced back from the low-oxygen levels of last winter, and now a huge mass of oxygen-depleted water is building up at the bottom of the canal, according to oceanographer Jan Newton, who heads the Hood Canal Dissolved Oxygen Program.

Normally, by this time of year, a band of dense water containing greater amounts of dissolved oxygen has pushed in from the ocean and lies at the bottom of the waterway. But that band, which scientists call an intrusion, is missing this year, leaving the canal with a greater oxygen deficit than ever seen before, based on data going back to the 1950s.

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