Home hazards in Colorado are both human created hazards combined with geological hazards and soil instability. 

RADON – Radon is a common radioactive hazard for the interior of homes in Colorado that should be checked and mitigated if necessary due to naturally occurring uranium underground; particularly, in the mountain areas.  About 50% of homes in Colorado have unsafe levels of radon due to underground naturally occurring uranium. Uranium decays to create radium which then decays to radon. It travels up fissures in the ground, so if one house is above a fissure, it can have a high level while the neighboring homes have a low level.  

The EPA states the unsafe level of radon is 4.0 pCi/L (picocuries per liter) and higher.  A 4.0 pCi/L level means in one liter of air there are 8.8 radioactive disintegrations per minute leading to 8.8 alpha particles. Alpha particles interact strongly with human tissue and can eventually lead to cancer of the lung. It is the second most prevalent cause of cancer – smoking is first; however, smoking magnifies the cancer risk from radon about 50 times.  So, in essence, smoking suppresses the ability of lung tissue to destroy cancers when they form.  The other thing that is fortunate with radon is alpha particle radiation is very low energy and can only travel about a centimeter in air. So, the radon gas that affects the lung is right up against the lung tissue where the alpha particles it creates

EPA - House Radon Sources
EPA -House Radon Sources

during disintegration can reach and interact with it. The truth is, there is no level where one can say radon is “safe.”   To put the exposure concentration of radon in perspective, radon exists in all 50 states and just going for a walk outside exposes a person to an average of 0.4 pCi/L or 1/10th the unsafe level established by the EPA..

RADON MITIGATION – Fortunately, there are radon mitigation systems that can be installed to lower radon levels in homes below 4.0 pCi/L – quite often close to the ambient air level; even in homes with levels far higher than the EPA safe limit.  These mitigation systems vary in cost depending on the home design – generally between $800 and $5,000, and most often between $800 and $1,500.  Given how prevalent high levels of residential radon exist, I always advise my home buyers to have a radon test during the inspection period. The radon test not only provides crucial information about the health and safety of living in the home but it creates an opportunity to negotiate with the seller to either install an effective radon mitigation system or credit the buyer at closing the cost for the installation of a radon mitigation system after obtaining bids. Given possible cost over-runs over the bid price (for any repair after closing), it is common practice to escrow 150% of the bid amount for the repair. The title company holds the escrowed funds.

CLAY SOILS AND DIPPING/HEAVING BEDROCK – Some locations have ground where the bedrock is moving up and down. There are also many areas where the soil has a high content of bentonite clay.  These are not health hazards, but they are a potential hazard to the health of a home’s foundation; causing them to sink, heave and crack, and possibly causing structural failure. In severe cases, such soil issues can cause structural damage in the 10’s of thousands of dollars.In many areas this soil movement is a very slow and mild, and not a huge problem while in others it is aggressive. These problems tend to exist most often around the Table Mountains,

Front Range Hogbacks From Red Rocks
Front Range Hogbacks From Red Rocks

Green Mountain and east of the Hog Backs at the foot of the rocky mountains – up to two miles east in some areas.  Due to many lawsuits in the ’70s and ’80s, local building regulations and design requirements were modified in 1995 to reduce or eliminate the effects of clay soils and moving bedrock.  With all homes, inspections should be performed to uncover any issues with settlement to determine if they are minor or serious issues; and whether further inspection by a structural engineer is a reasonable choice. The first places one sees the effects of clay soil (Bentonite Clay) and moving bedrock is in concrete slabs that lay on the ground (slab-on-grad or flat-work); such as sidewalks, garage floors and basement floors.  Foundation walls are much stronger and deeper and often have rebar reinforcement, so they are less vulnerable when settlement is very limited. While a hairline crack in a foundation wall may not be a serious issue in a particular case, a gaping crack is likely to require a foundation repair/mitigation involving steel reinforcement designed by a structural engineer.

PLUTONIUM – Rocky Flats between Golden and Boulder was a factory that made the plutonium triggers for nuclear bombs. This facility had two fires in the facility, one in the ’50s and one in the ’60s due to the tendency of plutonium to get very hot when concentrated. It was the 50’s fire that was the worst incident by far. It burned through the ventilation system spreading plutonium fallout across a wide area north

Rocky Flats Site July 1995 Before Final Cleanup
Rocky Flats Site July 1995 Before Final Cleanup

of Golden and South of Boulder and then out to the east and northeast along with the prevailing wind pattern at the time. Most of it was close the plant, which included leaking storage containers which leaked into a stream feeding into Standley Lake (this is why one can’t swim in Standley Lake).

  The area around the plant was declared a Superfund site, and the plutonium was corralled into containers and put into a concrete vault surrounded by a chain-link fence.  The cleanup also involved bringing in a lot of fill dirt to cover over the contaminated soil. This cleanup area is now a park called the Rocky Flats National Wildlife Refuge; however, many won’t go there due to safety concerns of possibly stirring up contaminated dirt. The half-life of Rocky Flats plutonium-239 is 24,100 years (the time it takes for half of it to decay). So, it will remain for hundreds of thousands of years- wherever it exists.  

It is fortunate that, like radon, when plutonium disintegrates it also creates a weak alpha particle radiation that can only travel about a centimeter in the air (far, far less in human tissue). Given alpha radiation can’t travel over significant distances, the most significant risk is to inhale a plutonium particle and have it attach to the lung or other tissue inside the body. On the flip-side, alpha radiation interacts strongly with human tissue, so if a particle can get close enough to human tissue and it remains there for a long time, it will likely be carcinogenic. The body will often retain a particle for decades; it’s very hard to eliminate.  If I lived in the fallout zone, I would avoid digging or disturbing the ground. Covering the soil in the yard areas with fresh fill and then a lush lawn, rock patios, AstroTurf, etc. would be desirable.  If I wanted to have a garden or plant flowers,  I would put these plants in a raised bed with fresh soil purchased at a home and garden supply. It seems reasonable that over the intervening decades, the rain, and melting snow have driven much of these fallout particles farther down into the ground, and the wind has dispersed most of the fallout particles laying on the surface over hundreds and thousands of miles. So, in totality, the risks should be very limited if one takes some basic precautions. Many people don’t have a concern about it, but I’m a very cautious person.

LEAD IN PAINT, PIPE, FIXTURES AND CERAMICS –  Lead is not an issue specific to Colorado, but rather of a time in the past, like under the current administration, when the corporate will was more powerful than the will of the people and the recommendations from scientific authorities.

Lead was even put into gasoline as an anti-knocking additive starting in the 1920s until banned in 1995. This raised the lead levels in the general population to alarming levels due to breathing in lead particles from the emissions of millions of vehicle exhaust pipes or absorbing it through the skin when contacting gasoline. It had many uses, which made it profitable. So, no surprise industry put it in paints to enhance color, and make it more durable and less prone to mildew. Lead has also been used in the manufacture of ceramics, varnishes, pipe, and fixtures. In January of 1979, the will of the people finally overcame the use of lead with the help of the EPA making it illegal. However, contractors were allowed to use up their supplies already purchased; so given that loophole in the ban, I would recommend lead inspections for homes built even as late as the 1980s.

It would be wrong to say it can’t exist even today in new construction, so given the low-cost of testing why not have a lead inspection done for peace of mind regardless of the age of the home? I’ve seen it in tested positive in floor tile, old ceramic sinks, and paint. Here is a scenario to avoid, which happens in real life – A buyer purchases a house built around 1978 or earlier never having had a lead inspection. The homeowner, with young children, decides to put a hammer to a wall old sink, tile, remove a wall, change out the old wood floors or refinish the wood floors with sanding. It could be just putting a small hold in a wall or sanding some small painted or varnished surface in the house – it could be just be sanding an old door knob. This activity spread lead dust all over the house. Lead is absorbed through the skin and into the bloodstream. For young children without a fully formed blood-brain barrier, which typically happens around the age of 10 years, develop what looks like attention deficit disorder. After some tests, a physician informs the parents their children have had significant brain damage from lead poisoning and will be mentally retarded for the rest of their lives.

I should mention lead exposure can also affect adults the same way as children and it can cause other medical problems; such as cancer.

Fortunately, prevention of serious lead problems is usually easy and inexpensive. Before buying a home, one can hire a lead inspector to check every surface in a room and the entire house, both on the interior and exterior. It’s very inexpensive – approximately, a few hundred dollars. They use an isotope gun that penetrates painted surfaces – it looks like a large version of a Star Trek Phaser. So, while most lead-based paint is sealed safely below newer lead-free paint (when it isn’t peeling or chipped), the lead inspector can inform a home buyer where lead exists in a home. Knowing where the lead exists allows the homeowner to then interact with their home in a way that protects their health and all occupants.

ASBESTOS – Like lead, asbestos is another case of putting profit above people which resulted in this hazard found in a myriad of products and homes across America. The current administration has removed the ban on asbestos, so we may soon have it back into products – so beware!

Anthophyllite Asbestos
Anthophyllite Asbestos

Asbestos is the name given to a group of silicate rock minerals that are composed of extremely small fibrous long crystals – it isn’t just one mineral. A single crystal is so small in diameter and light that it can float in the air indefinitely – this is a nefarious problem with asbestos. It doesn’t take much to get a great deal of it in the air. Once inhaled it lodges itself into the lung tissue. The surface of this crystal is very irritating to human tissue, and the interaction develops scar tissue which often leads to cancer over time. Imagine the lung tissue is constantly moving, expanding and contracting when breathing but the asbestos crystal is like a rigid plank – hence, the irritation. It is so small and sharp that once it embeds itself into tissue the body normally can’t remove it, although it may work its way to more interior tissues in the body as in mesothelioma, where a malignant form of cancer forms in the tissues surrounding the lung or stomach.

Asbestos was used in vehicle brake pads and clutches, pipe insulation, floor, and ceiling tiles sprayed on “popcorn” ceilings, sprayed onto steel beams in office towers, used in gaskets around wood stoves, and it can found in many other building materials. The US banned asbestos in 1989 with a phase-out period. Earlier, in 1973 asbestos was banned for most spray-applied products – common for insulating and fireproofing purposes. However, asbestos can still be found in some brake pads and older products. For example, the gasket around the door of a woodstove is suspect.

A home inspector will cite the location of any probable asbestos in the home. If such appears to exist, then one can request a test done by taking a small sample to a lab for testing. If a home has popcorn ceilings, it’s best to check it for asbestos. One doesn’t want to remove it or disturb the popcorn ceiling in remodel. Once can keep it in place by covering it over with drywall or use a company that specializes in its removal.

TOXIC MOLD AND INDOOR AIR QUALITY – Fortunately, toxic mold or any mold is less prevalent in Colorado due to it having relatively dry air. However, that doesn’t mean a particular house can’t have mold or toxic mold, or a particular location may not have high humidity in Colorado. There are many ways to create the humidity necessary to spawn mold and

mold spores and mycotoxins. Situations that can create the conditions favorable for mold – leaks in roofing, leaking pipes, bathing areas and homes that are not well ventilated, condensation from windows. Also, the use of humidifiers, living in a heavily treed location or adjacent lakes, rivers and ponds with little direct sunlight, improper drainage around a house, the pooling of water around the house during wet weather, leaking basements, defective siding that allows the penetration of water, among other reasons.


While it is said that black mold is the toxic mold, any mold can produce toxic mycotoxins— the greater the moisture, the greater the danger. I’d recommend a mold test if there is any hint of dampness, mold smell, or if there is a known leak in the house in the past or present.

Indoor air quality can also be a home hazard for two reasons:

1) Our modern houses are much more air-tight to be energy efficient; however, this is why new homes need ventilation fans that turn on regularly throughout the day and evening to maintain a minimum amount of whole-house ventilation. These fans are normally set to operate on a timer. It may only be the bathroom fans that are used for this purpose – quite often that is sufficient. They should be high-quality fan fixtures, that operate quietly, efficiently, and are built to endure frequent use.

2) Building materials, interior furnishings, electronics, and various  household products give off toxic gases – it is called out-gassing. Building materials like plywood, particle board, and foam insulation can out-gas formaldehyde and volatile organic compounds (VOCs).

If one is building a house, one can choose to do so with materials that do not out-gas toxic substances. However, one should also consider that carpeting, mattresses, upholstery, interior paints, and furniture can all out-gas toxic chemicals – so there are plenty of opportunities to choose products that do not out-gas toxic substances. But even if one has managed to build a house with no toxic out-gassing (a rare one indeed!), there are so many household products used that are toxic (cleaners, dryer sheets, air fresheners, nail polish, electronics, non-stick pans, laser printers, and photocopiers, among others. Not to mention, the people and pets in the home breath out carbon dioxide.

The point is, no matter how toxin free we try to make our homes, we need to ventilate them -to reduce chemicals, humidity and other pollutants in the air; as well as cooking smells.

During the inspection phase of a home purchase, it is important to have an air-quality test, which may include mold testing, performed for those home buyers that have allergies, asthma or other sensitive health conditions.

MISCELLANEOUS HOME HAZARDS – I’ve covered the most common general home hazards, but other can exist. Many hazards are property specific and have to do with construction, drainage, proximity to mines and slag, test pits, flood zones, etc.  .

Colorado is a beautiful place to buy real estate, with caveats. Please protect yourself, be an informed buyer, and avoid buyer’s remorse.  Use a reputable real estate agent/Realtor that will work for you as your “buyer’s agent.”  I hope you’ll consider me to guide you through your home search, home vetting, inspections, negotiations with the seller, and the overall buying process as your Realtor/agent.  
PS: While my working as a Realtor/agent and having been a real estate appraiser for eleven years has informed me in these matters, I also earned a Bachelor’s degree in human chemistry and biology (Biochemistry) at the University of Washington.  I am committed to creating awareness of radon and other home health hazards as an Ecobroker, and I have a certificate from Radon Aware attesting to having received education on radon and committing to create awareness of radon with the general public. I use my knowledge to inform my clients. 
Golden Colorado - North and South Table Mountains
Golden Colorado – North and South Table Mountains