An orange-colored substance was mysteriously washed up on the shores of the village of Kivalina in northwest Alaska.

Authorities say the orange goo is not a petroleum product nor man-made and it’s causing concern for residents that it may be toxic to humans.

According to the Associated Press, tests have been conducted on the substance on the surface of the water in Kivalina (KIV’-uh-LEE’-nuh) which also reportedly shown up in some residents’ rain buckets.

Photo by Kivalina resident Mida Swan