Celebrating with some mylar balloons tonight? NV Energy is asking you use them responsibly. Mylar balloons have caused thousands of power outages, so the energy utility is reminding customers to keep them secure during New Year’s celebrations. Mylar balloons are helium-filled balloons that are coated with a metallic finish. If they come in contact with power lines, they can cause equipment to fail resulting in a power outage. NV Energy recommends tethering the balloons, and when it’s time to throw them away, puncture them to release the helium. Most of all NEVER try to retrieve the balloon from the power line, instead contact NV Energy to report the problem.