The public is allowed to enjoy the water at Lake Siskiyou again after the lake was closed to swimmers Tuesday afternoon. A bright green substance was found near the north shore of the lake, and officials urged the public to avoid swimming in the lake. After testing, it was determined that the substance was an approved food-grade coloring used to test storm drains. Apparently an excessive amount was released which caused the concerning green color. The lake reopened to swimming on Wednesday morning.