Beachgoers in Maine and New Hampshire have reported a “bizarre” situation in which their feet have become stained after walking on the beach, according to News Center Maine.

  • “I’ve never seen anything like this,” Jenny Greenleaf, a book designer and beachgoer, told The New York Times. “It was almost like I walked through charcoal.”

Theories on stained beach feet

There are multiple theories out there about the origin of the dirty feet. For example, some consider it to be a result of algae and oil.

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John Lillibridge, who recently retired from the National Oceanic and Atmospheric Administration, told WMTW that it’s not linked to algae, though.

  • “Much to our surprise, it wasn’t some kind of algae or an oil spill like you would expect, it was just a whole bunch of dead bugs in the water,” he said, according to WMTW.

Another theory — which The New York Times said is a “fringe theory” — is that a submarine in the area might have released something to dirty the beach.

Why your feet are stained from the beach

But Jim Britt, a spokesman for Maine’s Department of Agriculture, Conservation and Forestry, told The New York Times that the dirtiness is likely linked to black kelp flies.

  • These flies that “feed off decaying seaweed appeared to have died on one stretch of beach,” The New York Times reports.
  • “It’s not known why,” he told The New York Times. “Nature does crazy stuff. This might be one of those instances.”

Similarly, the Maine Department of Agriculture, Conservation and Forestry told News Center Maine that the flying insects may be to blame.

The coloring is likely due to a “pigment from the bodies of flying insects deposited on the shore by waves.” 

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