400,000 black balls protects the quality of Los Angeles drinking water

400,000 black hollow plastic "shade balls" were dumped in Ivanhoe, which remains in use, in the hopes to reduce the likelihood of the sunlight-fueled bromate. Silver Lake Reservoir, too large to cover, was taken offline permanently. This incident pointed out the necessity of protecting the water supply by using underground tanks. The black plastic balls were created in Allentown, Pennsylvania by Orange Products Inc. The balls are also used at airports to prevent birds from landing in the water runoffs to keep the birds from getting sucked up by the planes. The balls were certified by the NSF International which certifies the safety of food, water, and consumer goods.

The colour is black to fight UV degradation and is the result of the addition of carbon black. Conceivably these could last 10+ years before needing to be replaced, but loss of balls from wind loading is also an issue.