Adult female sea turtles will not emerge from the water to nest and lay eggs on beaches that are bathed in artificial light. Hormones regulate growth and immune functions. But they're not produced all the time. If they don't shut down, you overload the body. It can't get rid of them.
Hormones are toxic in the wrong amounts.
Indeed, a 1998 study at the Mary Imogene Bassett Research Institute in Cooperstown, New York, found that cancerous liver cells in lab rats grew rapidly when they were constantly exposed to light. Lights Out Turn off lights whenever you leave a room. Close window blinds at night to prevent lights from shining outward. Turning off a few lights makes a big difference in conservation. Buy Design Use lights that have shields on their tops or sides so that they illuminate only where they're supposed to.