Category Archives: Radon Testing Services

Residential Radon Gas Testing – Mold and Indoor Air Quality Inspection by ScanTech Technical Consulting

Radon is one of the leading causes of lung cancer

Radon is one of the leading causes of lung cancer in the United States

In a rush to test your home for radon gas or radioactivity in natural stone such as granite or marble? Did you know that radon is the 2nd leading cause of lung cancer? (Smoking is 1st and radon gas synergistically increases mortality rates for smokers)

While it is not well known, radon gas levels EXCEED EPA action limits of 4 picoCuries/liter (pCi/L) in up to 10 % of all homes in Dallas county with an additional 14 % falling into the marginal range of 2 – 4 pCi/L. This means that 1 out of 4 homes (10 % + 14 % = 24%) in Dallas either have a radon issue or fall into a caution category. Other counties, such as Tarrant, Collin and Denton are not immune either. (see the link below on Radon FAQ from ScanTech for more details)

Example areas of the Metroplex (not a complete or comprehensive list) which have been found by ScanTech testing to have excess radon levels which are statistically higher than the 24 % quoted above include:

  • North Dallas and Far North Dallas
  • Lake Highlands
  • University Park
  • Highland Park
  • Park Cities area
  • Richardson
  • Arlington

ScanTech now has the capability to test and get results within as little as 24 hours of initial deployment using a high quality digital tester in case your option period is about to expire.

Our services are both faster and cheaper than competing methods or companies and we have been performing radon testing for homeowners in the DFW area for over 10 years.

Testing is performed by an engineering graduate experienced in radioactivity measurements,  indoor air quality testing including mold inspection, formaldehyde and radon gas testing.

AARST NRPP National Radon Testing Professional Certified

AARST-NRPP Nationally Certified Radon Residential Measurement Provider ID # 108991 RT*

*Meets HUD, Fannie Mae, Freddie Mac and GSA requirements

Mold Assessment Consultant – Texas Dept. of Health Service License # MAC1387

(Activated charcoal short term radon test kits are accurate as well, but typically require at least 4 business days to get results under best case conditions and a complete kit deployment and pickup service is almost always more expensive due to the additional travel)

Call / text to 214.912.4691 – please include physical address, square footage property and email

More information is available here:

RADON FAQ Dallas /Fort Worth — DFW North Texas Area

Radon Deaths United States Annually

Annual Radon Deaths Updated Chart

Cities for radon / air quality inspection services include: Dallas, Austin, Houston, San Antonio, Spring, The Woodlands, Round Rock, Plano, Highland Park, University Park, Park Cities, Arlington, Fort Worth, Grapevine, Frisco, Denton, McKinney, Allen, Lewisville, Irving, Mesquite, Bedford, Euless, Richardson, Coppell, Grand Prairie, Garland, Addison, Farmers Branch, Rockwall, Carrollton, Parker, Rowlett, Lucas, Fairview, Park Cities, Keller, Roanoke, The Colony, Highland Village, Lake Dallas, Corinth, Prosper, Duncanville, Lancaster, Rowlett, Royse City, Trophy Club, Southlake and Hurst. Counties served include Dallas, Collin, Denton, Tarrant and Rockwall County.


Radon Gas Risk Factor Safety Levels Comparison

How do you put the risk from radon into perspective, especially since all homes contain some level of radon gas in them and there is no “safe level” except zero?

I have found the following charts to be helpful in evaluating risk: (please click on the pictures for a full sized detailed view)

Radon Gas Safety Cancer Risk

Radon Gas Chart Safety Level Relative Risk Factors

Radon Risk Smokers Non-Smokers

Radon Risk Chart for Smokers vs. Non-smokers

Notice that the risk for a radon level at the EPA action limit of 4 picoCuries/liter is similar to the same risk of dying in a car wreck. I have personally observed several residences that I have tested in Dallas county to EXCEED this limit including my own home.

Radon is linked to not just lung cancer, but recent epidemiological evidence also suggests that radon gas may also be a risk factor and contributor to

  1. Acute Myeloid Leukemia (AML)   13 % – 25 % of all cases worldwide.
  2. Kidney cancer
  3. Certain childhood cancers
  4. Melanoma

Radon Gas Testing Methods & Equipment

There are a variety of ways to monitor the radon levels in a residence, home or commercial building and the best detector for your needs depends on balancing cost, accuracy, ease of use and type of application such as a long or short term test.

The chart below gives a comparison of different detectors including the time period duration during which radon is measured.

Comparison of Different Radon Detection Methods

Comparison of Different Radon Detection Methods

Radon & Radioactivity Measurement Safety Guide

Measuring radioactivity from radon is potentially very confusing for the lay person for several reasons. One of which is that there are several different units of measurement depending on the application, era of standards and preference based on world regionalisms. Applications include activity, (which radon measurement falls under) absorbed dose, which is the measure of radioactive energy absorbed by tissue per unit mass and dose equivalent which is the measure of absorbed doses from DIFFERENT types of radioactivity such as alpha, beta, and gamma radiation. Many scintillation meters still measure this in the older measurement unit rem (Roentgen Equivalent Man) or microrems for gamma radiation.

For instance, when measuring radon, North America prefers to use the picoCuries per liter (pCi/L) designation as opposed to Becquerels  or Bq / meter^3 which is typically used in Europe and the UK. These both measure a specific number of atomic disintegrations per volume of space.

In the case of the Becquerel, this is 1 atomic disintegration per second or 60 events per minute. For a picoCurie, this is translated as 2.2 radioactive disintegrations per minute. A convenient conversion chart is shown below.

Just as a quick conversion from the picoCurie/liter to the Becquerel / m^3:

1 picoCurie / liter = ~ 37.1 Bq/m^3     EPA action limit 4 pCi/L = ~ 148.4 Bq/m^3

Units of Measurement for Radioactivity and Dose

Units of Measurement for Radioactivity and Dose

As an added note, a little known unit of radon is what is known as a Working Level (WL) which is the quantity of radon that will produce 1.3 X 10^5 MeV (Mega Electron Volts) of potential alpha particle energy per liter of air. A single WL of radon is equal to the RDP’s (Radon Decay Products) in equilibrium with 100 pCi/L of radon. Because the equilibrium value for RDP’s for indoor environments is typically 0.5, radon concentrations of 1 WL would be around 200 pCi/L.

Entry Routes and Factors Affecting Indoor Radon Levels in Homes

Many people wonder how radon gas levels could be present in Dallas / Fort Worth Metroplex DFW area – how does it get inside your home and affect your health and safety?

The fact is that all parts of the Earth, regardless of geography, have some level of background radiation due to nuclear disintegrations of naturally occurring radionuclides (radioactive isotopes) including uranium in the soil, water and air. On average, rocks contain only about 1-3 ppm of uranium, though some species have as much as 100 ppm. These are typically metamorphic minerals such as granite, black shale, schist, gneiss, phosphorites, some sedimentary rock (including limestone in some cases) with a high phosphate content and metamorphic rocks derived from these rocks.

On average worldwide, the radioactive concentration of U-238, Thorium-232 and Radium-226 are ~0.65 pCi (picoCuries) per gram though this can vary significantly in very localized areas.

Radon geology home construction

Radon Intrusion Paths into Home

The major source of indoor radon is soil gas transported by pressure-induced convective flows (as shown in the illustrations) with potential entry points marked. Radon transport is enhanced when the base of the building is under significant negative pressure. Homes built on soils with higher radon release (based on soil type, porosity, pore volume, water content, etc.) and convection based transport are typically more sensitive to atmospheric factors such as temperature, wind and barometric pressure. Radon movement through soil can also occur through diffusion or both diffusion and convection.

Homes built on soils with a higher clay content (as opposed to those with sandy / gravelly soils) tend to have lower radon gas levels, but there may be trade-offs with higher moisture levels which can give rise to issues with mold, dust mites and general structural deterioration.

What are the major entry routes into your home?

1) Cracks in concrete slabs

2) Spaces behind brick veneer walls that rest on uncapped hollow-block foundations.

3) Pores and cracks in concrete blocks.

4) Floor wall joints.

5) Exposed soil as a sump.

6) Drain tile, if drained to an open sump.

7) Mortar joints.

8) Loose fitting pipe penetrations.

9) Building materials including some rocks and other decorative stones such as marble and granite.

10) Drinking / tap water.

11) Open tops of block walls.


Atmospheric Factors with Radon Levels in Homes

Atmospheric Factors with Radon Levels in Homes (Animated Graphic)

What factors affect indoor radon overall?

1) Low ventilation rates.

2) The nature of soil permeability. (by diffusion / convection mechanisms)

3) Construction materials used. Can be a significant factor in natural stone where Radium-226 concentrations are elevated. (exceed 1 pCi/gm or 1 picoCurie per gram) Emanation depends on radium density and material porosity.

4) Home water supply.

5) Meteorology (such as temperature, pressure and humidity) and the local geology of the environment.

6) Soil radon production rates based on radioactive material composition (most in the U.S. have base radon concentrations between 200 – 2000 pCi/L)

7) Cracks and fissures in the underlying geology

8) Building substructure (slab on grade, pier and beam, basement, etc.)

EPA Working to Make the Public Aware of Radon Gas Risk in Homes – North Texas News Story

A local Texas story about radon wherein a local Dallas woman found twice the EPA action limit in her home after she was told residential home testing wasn’t necessary:

A Story of Elevated Radon in Dallas – The Cancer Risks

I have personally verified a number of homes that exceeded the EPA action limit including one that had radon levels even higher than mentioned in the article.

So Much of Texas is Considered Zone 3: Is it Safe? (free from Radon Gas)

I recently had a client inquire about my services and asked for an official proposal. Before I could respond, within 30 minutes they sent a follow up message saying that because the Dallas / Fort Worth area is considered a Zone 3 region according to the EPA, that testing isn’t necessary.

This is a serious misunderstanding of what the different radon gas Zone designations mean, even according to the Environmental Protection Agency which states explicitly on their website:

“All homes should be tested, regardless of zone designation.”

“All homes should test for radon, regardless of geographic location or zone designation.”

While a structure located in Zone 3 has a statistical likelihood of having a lower level of radon, there are still thousands of homes, residences and structures in the DFW area that will exceed the action limit of 4.0 picoCuries per liter if tested. I have found several myself in the course of testing as this percentage of homes is 10 %. It is not probable, but a 1 in 10 chance is fairly high when gambling against the chance of lung cancer.

I have found a number of homes in the North Dallas area (including mine) whose radon levels are high enough to warrant mitigation. With radon gas now killing more people than drunk drivers, it is well worth the small investment to get your residence checked.

Radon: The Radioactivity Decay Pathway

Below is a detailed chart showing the radioactivity pathway to radon from the original U-238 atom. Also shown are the different types of radiation:

Alpha Radiation – (from Radon-222 as an example) high energy helium nuclei (almost no penetrating power, but does a great deal of damage at close range to cells and DNA – will not penetrate outer layer of skin, but can cause direct harm to epithelial cells in the lungs if inhaled) It causes approximately 5 X the damage of gamma Radiation or X-Rays.

Beta Radiation –  high energy electron (much lighter than an alpha particle but it has a greater penetration)

Gamma Radiation – high energy photon (essentially without mass but has a high penetration factor through shielding)

Penetration and of Alpha, Beta and Gamma Radiation

Penetration and of Alpha, Beta and Gamma Radiation

If you follow the diagram below, the radioactive decay of Radon-222 to Lead-210 results in the emission of 3 alpha particles, 2 beta particles and a discrete amount of gamma radiation. (the nature of which is an electromagnetic wave, not a particle) Because radon decay products (RDPs) are electrically charged particles, they readily adhere to suspended dust particles (which can be inhaled) or other surfaces in a phenomena known as “plate-out”. Either pure RDPs or the particles they are attached to can be inhaled.


Radon gas decay pathway

Radon Gas Decay Chart

Medical Geology Post on Environmental Radon

General radon levels in the environment can vary greatly, depending on locale and the medium it is measured in. Here are comparisons between indoor/outdoor air, soil air and groundwater.

Again, the conversion factors are from the picoCurie/liter to the Becquerel / m^3:

1 picoCurie / liter = ~ 37.1 Bq/m^3     EPA action limit 4 pCi/L = ~ 148.4 Bq/m^3


Radon:  Outdoor air      Low of 4 – 8 Bq / m^3    =  0.2 – 0.3 picoCuries/liter

High of 100 Bq / m^3 in valleys (morning time)  = 2.7 picoCuries / liter

Radon:  Indoor air  Low  20 Bq / ^3  = 0.5 pCi/l

High of 110000 Bq / m^3  = 2964 pCi/l  (probably over a uranium mine)


World average  39 Bq / m^3   = 1.1 pCi/l



Egypt:   9 = 0.2 pCi/l

UK:  20 =  0.5 pCi/l

USA:  46 = 1.5 pCi/l     Texas  48 = 1.3 pCi/l

United States by Region:  (geometric mean values)  3.43 pCi/L in the Northeast   2.36 pCi/L in Midwest, 0.64 in the Northwest, 2.40 pCi/L in the Mountain States, 1.43 pCi/L in the Southeast

Sweden:  108   = 2.9 pCi/l

Czech Republic: 108 = 2.9 pCi/l

Highest ever radon concentration ever reported in an indoor dwelling:   2600 pCi/L in a southeastern Pennsylvania home which is equal to a 4 pack a day smoker.

Radon in soil air:   Ranges from less than 1 to over 2500 Bq / liter  = 0.03 – 67.4 pCi/l

Most soils in the USA are between 5 – 55  Bq/liter  = 0.13 – 1.48 pCi/l

Radon in groundwater:  3 – 80000 Bq/liter  = 0.081 – 2156 pCi/l

Radon Gas Mitigation Solutions in Brief

While I do not personally perform radon mitigation, I wanted to share in brief what is generally entailed. The cost in the Dallas area for reducing radon below the EPA action limit of 4.0 pCi/l varies depending on the construction / size of the house and how high the levels are. In general, you can expect an estimate of anywhere from $2000 – $5000.

It is suggested that the solution follow the ASTM E-2121 standard for lowering radon and that information can be found in detail here:

While homes that contain excessive radon can be found in every state in the nation, many people (such as in Texas) are not aware that it is a problem, nor is testing / mitigation required by Texas law as of this writing. However it is not unusual for some relocation companies to require testing for radon gas first as a condition of a real estate purchase.

Bear in mind that radon levels do fluctuate with weather conditions and home ventilation, so before investing in a mitigation expense, it may be worth testing more than once.

The main idea behind mitigation is to ventilate the excess radon (which is heavier than air) to the outside so as to minimize impact to occupants. The method by which this is done depends on whether you have a basement (rare in the Dallas/Ft. Worth area) have a pier and beam or slab on grade foundation.

For slab foundations, sealing the interior spaces from the ground is generally not enough, and often a soil suction system is required to actively draw the radon out via a vent pipe and specialized fan. These systems are generally referred to as active soil depressurization, sub-slab depressurization or just simply soil suction.

In some cases, a heat exchanger or ERV (Energy Recovery Ventilator) can recover some of the energy lost in the process of exchanging the vented radon to the outside with fresh air.

For pier and beam foundations (houses with crawlspaces) you can cover over the base soil with a special heavy duty plastic sheet whose underside connects to a ventilation system similar to the one described above in a method known as sub-membrane suction.

Sub-membrane Suction Radon Mitigation

Sub-membrane Suction Radon Mitigation