A big mess along I-75 in Oakland County may sound gross — but it’s no danger to public health, according to police. Northbound I-75 was reduced to two lanes Wednesday near the Chrysler Dr. exit, north of M-59, after a semi truck hauling two trailers carrying an estimated 50 to 55 tons of solid human waste overturned. Auburn Hills police said the trailers lost their loads off to the side of the freeway, but stressed that this is "treated human waste," so it is not a hazardous materials situation.