Did you know that if you live in the United States, there is an estimated 90% chance that you are sleeping just underneath an ionizing radiation source?  The effects of low-level radiation exposure includes DNA damage and cell death in the short-term and serious disease (including cancer) and death in the long term.

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By now, you are probably well-aware of the dangers of Radon, a radioactive particle that is the 2nd leading cause of lung cancer.  Radon is most likely to enter your home through cracks in your home, usually near the foundation of the building.

But there are several other ways that radioactive elements can get inside your home.  This article will discuss the 3 sneakiest ways that you may be exposed to radiation in your own home.

1. Smoke Detectors

Be honest, when was the last time you thought about your smoke detector? If you’re like most people, it was the last time that burnt toast tripped the alarm or maybe that time you removed the batteries to avoid the psychotic break caused by the persistent chirp of your dying device.

The smoke detector is one of those no-thought purchases.  A glance at the package, a little price comparison, and in the cart it goes.  Turns out, your choice of smoke detector is a much bigger decision than you may have thought.

Here’s the long and short of it. There are two types of smoke detectors: photoelectric and ionizing.

Photoelectric smoke detectors sense smoke using light.  Ionizing smoke detectors sense smoke using radioactive material, usually americium-241.

It is worth noting that photoelectric devices can detect smoldering fires some 30-50 minutes or more faster than ionizing alarms.  So, in my opinion, photoelectric detectors are the best choice for a healthy and safe home.

Is My Smoke Detector Radioactive?

Probably.  In the United States, ionizing detectors are significantly more common, with some estimates as high as 90%.  Knowing for sure is a bit harder.

Unfortunately, unless you know the model number of your smoke detectors or still have the packaging, it’s hard to tell without taking the unit apart.  Sometimes you will see an “I” in the model number of ionizing units or a “P” on photoelectric ones, but not always.  Also, some states ban the sale of ionizing smoke detectors, so if you purchased your unit in Massachusetts, Iowa, or Vermont, your unit is photoelectric.

What to Do: Because (1) a vast majority of units sold use ionizing technology; (2) smoke detectors should be replaced every 10 years anyway; and (3) safer photoelectric alternatives are relatively inexpensive, I recommend replacing all ionizing detectors and detectors that use unknown technology as soon as possible.

2. Granite Counters

Granite, like other stone, can contain veins of naturally-occurring radioactive substances, including uranium, thorium or radium.  These elements can emit small amounts of beta and gamma radiation into your home.

Is My Granite Countertop Radioactive?

Could be.  There isn’t much in the way of scientific studies on the percentage of granite slabs that contain radioactive material, but an informal test from the Health Physics Society indicates that a majority of slabs measure around 1-1.5x background levels (with some testing significantly higher).

What to Do:  Officials in the EPA do not recommend removing granite countertops because of radiation concerns.  I suggest your home use a continuous radon monitor. If you are concerned about your slab or ready to purchase a new one, you can hire a building biologist or other healthy home specialist to test your granite, or do it yourself with an inexpensive Gieger counter.

3. Water

You may remember from middle school science class that water is a universal solvent.  It picks up just about everything it comes in contact with, including radioactive particles in the soil.  Once in the water, the radioactive elements can be swallowed,  or inhaled through shower vapors or cooking.

Is My Tap Water Radioactive?

It may be.  Unfortunately, there is no accurate way to know if your water is radioactive without testing.  Risk changes depending on your location, water source, and water treatment.  Generally, well water is more likely to be radioactive.  A study from the US Geological Survey found radon to be the largest contaminant of concern, present in some 65% of wells sampled.

What to Do:  

The first thing you need to do is test your water at the tap.  I suggest this radiation water test from TapScore.  Once you know what radioactive elements are present, you can choose a contaminant-specific filtration system.