Mylar balloons are great indoors, and can brighten the bleakest and most dreary winter day.  They are great at Valentine’s Day, birthdays, and many other occasions, but keep them inside.  And when you tire of them, deflate them and throw them away.  If you release them outside they can become trapped on overhead power lines.  Because the Mylar has a metallic coating, they conduct electricity very well and can short out circuits in your community’s power system.  You and your neighbors could lose power, traffic lights could go out, and entire blocks of homes and businesses could go dark.  If your name is on a card attached to the balloons, there could be some liability issues.

Mylar balloons have been known to float for several days before losing their helium and returning to Earth.  If one happens to land within the fence of an electric utility substation, it can cause electrical fires and untold dollars worth of damage after high transmission circuitry goes down.  Again, if the balloons can be traced by investigators to you, the cost of the damage will be your responsibility.

Mylar balloons can be festive at indoor events, but when their usefulness is gone, puncture them and discard them along with other holiday favors.  That will eliminate the potential damage they can cause if they are floating free near electrical installations and power lines.