Are Old Christmas Lights Safe? 6 Checks, Including Lead

Yes, old Christmas lights can be safe, but age is not the test. Condition is. The U.S. Consumer Product Safety Commission tells people to check every set, "new or old," for cracked sockets, frayed or bare wires and loose connections, and to throw out any set that has them. A string from 1995 with soft, whole wire and a lab label can pass. A string from last year that was yanked off a gutter and crushed in a bin can fail.

The box in the attic is not dangerous because it is old. It is dangerous if you skip the five minutes it takes to check it.

That matters right now. Late October is when the bins come down, and it is also when secondhand lights turn up at yard sales, thrift stores and online listings. Here is how to judge a string, whoever owned it first.

Are old Christmas lights safe to use?

They are safe to use when they pass an inspection and carry a mark from a recognized testing lab. In its December 2017 holiday release, the CPSC asked people to use only lights tested by a nationally recognized testing laboratory, to check outdoor sets are certified for outdoor use, and to plug outdoor lights into a GFCI-protected outlet (the kind with "test" and "reset" buttons) or a portable GFCI.

The same release estimated about 14,700 emergency-room visits for holiday decorating injuries in one season, roughly 240 a day across November and December. The biggest share, 41 percent, were falls, not shocks or burns, but the lighting rules are the ones you can check at the kitchen table before anyone climbs a ladder.

One thing the CPSC is firm on: never put electric lights on a metal tree. A faulty string can make the whole tree live.

How do you tell if a string of lights is worn out?

Unplug it, stretch it out on the floor in good light, and run it slowly through your hands from plug to tail. Here are the six checks, in the order you meet them.

If the string fails any check, do not tape it and hope. A damaged set goes in the electronics recycling pile, not back in the box.

What do the green and red UL labels mean?

The small holographic tag near the plug tells you where a set is allowed to go. According to UL Solutions, light strings meant for indoor use only carry a green holographic label, and strings rated for indoor or outdoor use carry a red one. UL tests these strings against UL 588, its safety standard for seasonal and holiday decorative lighting.

That makes the tag the single fastest check on a secondhand string. Green means it stays inside, whatever the seller says. Red means it was built to handle weather. No tag at all, or a tag that has been cut off, means you cannot tell what you are holding, and that is a reason to walk away even if the price is a dollar.

If the tag or the box gives a limit on how many sets can be joined end to end, follow it. If you cannot find a limit, do not chain that set to others.

Is there lead in old Christmas light cords?

There can be, and it is the risk most guides leave out. In a study published in the Journal of Environmental Health in December 2008, Cornell researchers tested 10 sets of indoor and outdoor lights, some bought new that year and some from the 1970s. Every set had detectable lead on its cords, and every set was over the EPA and HUD limits used for comparable windowsill and floor areas. Lead levels did not differ much by brand, by when the set was bought, or by how many years it had been used.

The lead comes from the plastic coating on the wire, where it helps keep the plastic from cracking and resist heat, sun and moisture. The researchers put it at about 2 to 5 percent of that coating.

The study is from 2008, so newer sets may differ, but the advice is cheap to follow with any string, old or new:

1. Keep young children from handling the lights.
2. Wash your hands with soap after putting lights up or taking them down.
3. Do not let anyone eat while untangling a string.

This is not a reason to panic about your tree. It is a reason to treat light cords like any other cord, and not like a toy.

Are vintage incandescent lights more dangerous than LEDs?

Not automatically, but they run hotter and draw far more power, so a worn incandescent string has less room for error. National Geographic, citing the utility PG&E in 2012, put a typical old-style incandescent holiday bulb at about 7 watts against 0.04 watts for an LED. ENERGY STAR, in the same article, said certified LED strings use 70 percent less energy and can last up to 10 times longer than incandescent strings.

Less power means less heat at each bulb and less load on the outlet when you join sets. That is why many people keep a few vintage strings for a mantel or window, where they can see them, and use LED sets for the big outdoor runs. If you love the old big-bulb look, the same six checks apply. Just be stricter about the wire.

Whatever kind you use, turn the lights off when you go to bed or leave the house.

Are old Christmas lights recyclable in the DC area?

Yes, but not in your curbside bin. The City of Fairfax, Virginia, says string lights jam sorting machines when they go into home recycling, and runs a drop-off program from Thanksgiving through Valentine's Day. Its page lists drop-off points at Fairfax Ace Hardware, Fairfax City Hall and the Old Town Alexandria Ace Hardware, and it takes LED, icicle, multicolored, rope and solar string lights. It also suggests donating sets that still work.

In Maryland and DC, programs and dates vary by county and year, so check your county's recycling page before you load the car.

The bottom line

Old or secondhand lights are worth keeping when they pass the checks: soft wire, whole sockets, a sound plug, a lab tag, the right indoor or outdoor rating, and matching bulbs. Wash your hands after handling any string. Skip any set with no tag, and recycle the rest the right way.

If you are shopping secondhand for the holidays, our guide to checking recalls before you buy used covers the next step, and our article on why tree fires so often start with lights or wiring has the fire-safety side. You can browse what is in stock now on the shop or see current auctions, and the FAQ answers how pickup and payment work.

Know someone hauling the light bins down this weekend? Send them this before they plug anything in.