80 million plastic balls to prevent Los Angeles reservoirs from becoming carcinogenic

The Los Angeles Department of Water and Power is buying 80 million 4-inch black polyethylene balls to cover the surfaces of three Los Angeles reservoirs that serve 4 million residents. At a cost of 33 cents each, the hollow spheres are designed to block sunlight from turning bromide and chlorine in the water into bromate, a suspected carcinogen.

Photos of the ball manufacturing equipment at XavierC in Glendora, California.