Many items you will buy and store for emergencies come with expiration dates printed on them. But what do they mean?

• Are they no longer functional?
• Are they not safe to use?
• Are they no longer dependable?

Making sure you have the right equipment when you need it is important during a disaster, but replacing everything just because a date has passed can be an expensive proposition.

I decided to test a Cyalume light stick that was 18 months past its expiration date (6.5 years after the manufacture date) to see if it would still function as needed.

The lightstick was undamaged and glowed brightly upon activation. The middle picture shows the bright glow even in a well lighted room. The picture on the right shows how brightly it glowed in the dark.

But would it last the length of time promised on the package considering how old it was? Here are pictures taken in a dark room after 9.5 hours and 12 hours. Grab the slider to move back and forth between the two pictures. Can you tell any difference?

As you can see, the brightness seems consistent for the full 12 hours.

This shouldn’t be much of a surprise. Cyalume, a leading manufacturer of light sticks, including the one I tested, has this to say about the expiration date.

In their packaging, SnapLight products are guaranteed to last for 5 years from date of manufacture, while ChemLight products are guaranteed to last for 4 years from date of manufacture. Many times, customers have shared photos of our light sticks working well after their expiration date, though we cannot guarantee this result.

The verdict?

It’s OK to leave expired glow sticks in your emergency pack. Although, I would also add some fresh ones to be on the safe side. I opened a package with a 2015 expiration date and the glass vial on the inside had already been broken and the glowstick activated inside the package. If that had been my only light source, I would have remained in the dark.

It’s good to have a few of these available. When wondering how many you should have, remember the saying, “Two is One; One is None.” If you only have one, and it breaks or doesn’t work, then you have NONE.