Recycling Mystery: Smoke Detectors & Carbon Monoxide Detectors

Reducing our consumption of material goods is a worthy goal. But some things you just can’t skimp on. When smoke detectors reach their expiration date, it’s time for them to go. Same with carbon monoxide detectors. You don’t want to mess around with something that can save lives. But when you need a new one, can the old one be recycled?

As with so many electronic products, end-of-life disposal is problematic. It usually takes time and effort to dispose of electronics responsibly. In nearly every case, you have to call a company or a local municipal office; cart your unwanted item somewhere; or hold onto stuff until special recycling or hazardous waste events take place — and then remember the date.

No wonder so many people don’t bother. It’s time-consuming and frustrating. We do it, though, because we know it matters to the health of the planet.

It would be nice if we had a better infrastructure for some of our recycling challenges, and hopefully, we will sooner than later. In the meantime, we’ve rounded up some information here to help you get started.

Different Types of Detectors

There are two different types of smoke detectors, ionization and photoelectric. If you’re not sure what kind you have, just look on the back. Ionization detectors will have an “I” or “ionization” printed on the unit.

  • Ionization smoke detectors contain an electrical circuit and a small amount of a radioactive isotope called Americium 241. Americium 241 converts air molecules into positive and negative ions that keep the electrical circuit moving and steady. When smoke enters the detector, it disrupts the electrical circuit and the alarm sounds. Americium 241 isn’t harmful to consumers when smoke detectors are used as intended. It only poses a risk if consumers attempt to disassemble the unit and break the protective casing.
  • Photoelectric smoke detectors don’t have any radioactive materials. Photoelectric models have an LED light that sends a steady ray of light across an inner chamber. When smoke enters the device, it scatters the light toward a sensor in the unit. The sensor detects the light and triggers the alarm.
  • Carbon monoxide detectors do not have any radioactive materials. Most programs will advise disposing of carbon monoxide detectors as you would photoelectric detectors. As you’ll see below, the advice for proper disposal of any of these items varies depending on which company you ask and where you live.

Why It’s Important to Recycle Smoke and Carbon Monoxide Detectors

As mentioned above, ionization smoke detectors contain radioactive materials that shouldn’t be thrown in the trash. Technology is available that can recover and properly manage those materials.

Most smoke and carbon monoxide detectors connect to home electrical systems. They all have backup batteries, though, in case the power fails. Older models run solely on batteries. All smoke detector batteries should be recycled.

Both photoelectric and ionization detectors contain circuit boards, metals — including gold, and plastic. Throwing all of that away is a terrible waste of resources and exacerbates our problems with plastic pollution. The World Economic Forum states, “The earth’s richest deposits of valuable materials are sitting in landfill sites or people’s homes. More needs to be made of these resources.”

Mixed Messages About Recycling

Even when we do some legwork to find out the proper way to dispose of smoke and carbon monoxide detectors, we get conflicting information.

For example, First Alert’s website says, “You can dispose of photoelectric alarms in regular household waste after the batteries are removed, or preferably recycled.” However, the company has informed Earth911 readers that the smoke alarms it receives through its mail-back program are thrown away, not recycled.

Kidde’s website says, “Typically, alarms may be disposed of in your regular, residential trash.” They go on to advise checking with your local municipality.

Surprisingly, the EPA says this: “There are no special disposal instructions for ionization smoke detectors. They may be thrown away with household garbage, or your community may have a separate recycling program.”

The EPA advising us to toss radioactive materials out with our trash? We can do better.

Options for Disposing of Smoke and Carbon Monoxide Detectors

Fortunately, with a little effort, we can find avenues that keep some of this electronic waste out of our landfills.

First up, manufacturers sometimes have programs that accept ready-to-toss smoke and carbon monoxide detectors. For example, First Alert will accept up to four ionization smoke detectors. The only fee is for postage. If you have more than four, First Alert charges a fee. Their website says they recycle components of the smoke detectors “when able.” They also note that some components are non-recyclable because of flame-resistant chemicals in the product.

Curie Environmental Services explains that California classifies smoke detectors as Universal Waste Electronic Devices due to their circuit boards and should not be put in the trash. (Curie also provides prepaid mail-in recycling services for ionization smoke detectors.)

EZ On the Earth, a Simi Valley, Calif.-based ewaste recycler offers mail-in smoke detector recycling for a fee.

To find local recycling centers and drop-off sites, try the Earth 911 search tool. Just type in “home electronics” and your ZIP code. You may find local facilities that recycle a variety of materials. Call ahead to confirm which items they accept.

You can also place a call to any of these local entities:

  • Your local recycling service
  • Your local Board of Health
  • Your local Department of Public Works

They may be able to tell you about upcoming household hazardous waste collection days for ionization detectors. Many municipal websites suggest throwing photoelectric and carbon monoxide in the trash, but they have recyclable parts (plastic, metals, circuit boards). Ask if they have recommendations for recycling centers that accept those models.

It can be hard to weed through all the recycling information out there. And to figure out who’s giving you solid information versus taking the path of least resistance. A word of advice? The wrong information will give you the easiest out. When it comes to recycling, consumers still have to do a bit of heavy lifting.

Editor’s Note: This article, originally published on September 8, 2021, was updated in August 2023.