Radon Control in New Home Construction: Developments in State Policy
July 2008
Background
According to the U.S. Environmental Protection Agency (EPA), indoor radon is the second leading cause of lung cancer in the United States and the leading cause of lung cancer among non-smokers. Lung cancer due to radon exposure is responsible for an estimated 21,000 deaths in the U.S. each year. See http://www.epa.gov/radon/healthrisks.html.
Radon is a radioactive gas found in soil and rock in all parts of the United States. The concentration of radon in indoor air is affected by the way we design and construct houses and other buildings. EPA has established an “action level” of 4 picoCuries/liter (pCi/L) — the level at which a building owner should take action to reduce radon in the indoor air.
The EPA Map of Radon Zones shows the radon potential for each county in the nation. Zone 1 counties have the highest potential radon levels, with predicted average indoor radon screening levels greater than 4 pCi/L, while predicted average radon levels are 2-4 pCi/L in Zone 2 counties, and under 2 pCi/L in Zone 3 counties. Although the map shows predicted average radon levels, high radon levels can be found in any area. The only way to know the radon level in a specific home is to test the home for radon. See http://www.epa.gov/radon/zonemap.html.
When a new home is built, radon control techniques (also referred to as radon-resistant new construction) can be used to help block radon from entering the home. The EPA has developed a voluntary guidance document on radon control techniques for new construction. The guidance recommends and describes the installation of a “passive sub-slab or sub-membrane depressurization system.” See U.S. EPA, Building Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes (2001), available at: http://www.epa.gov/radon/images/buildradonout.pdf. Because installing such a system does not ensure radon levels under 4 pCi/L, the guidance further recommends that “[t]he home should be tested after occupancy and the passive system should be activated [fan powered] if post-occupancy testing reveals radon levels at or above 4pCi/L.” See Building Radon Out at 30.
EPA also recently developed voluntary guidance addressing radon and many other indoor air quality issues in new home construction. The guidance, known as the Energy Star/Indoor Air Package, calls on builders of new homes in Zone 1 and Zone 2 areas to use radon control techniques and to provide home owners with radon testing kits and instructions for their use. See http://www.energystar.gov/index.cfm?c=bldrs_lenders_raters.nh_iap.
Certain non-governmental organizations have developed consensus-based, technical standards for radon control techniques in new home construction. For example, the International Residential Code (IRC), a model building code developed by the International Code Council, contains a radon control standard that calls for a passive (no fan) sub-slab or sub-membrane depressurization system to be installed in homes located in Zone 1 areas. Because the IRC standard is included as an optional appendix (“Appendix F”) jurisdictions that adopt the IRC as part of their building code must explicitly include Appendix F in order to establish the IRC’s radon control standard.
Another third-party standard is ASTM International’s ASTM E-1465 (“Standard Practice for Radon Control Options for the Design and Construction of New Low-Rise Residential Buildings”). One of the main differences between this model standard and the IRC Appendix F standard is that the ASTM standard requires pre-occupancy radon testing; if the testing indicates unacceptable radon concentrations, a fan (active system) must be installed. (For a description of the differences between the two standards, see http://www.aarst.org/images/Comparison_Appendix_F_and_1465_07_08.pdf).
State Policies
State and local governments can play an important role in reducing the risks from radon exposure. In addition to providing education and information to builders and consumers, states and municipalities can enact policies to help ensure that homes are built with radon control techniques. These policies can reference an existing radon control standard, or they can modify and adapt existing standards and guidance.
There are different ways that states can enact such policies. States that adopt state-wide building codes can include radon control techniques that are mandatory at the local level. States that have model state building codes can include radon control techniques that localities must adopt if local government chooses to establish a radon standard for new construction. States can also establish radon control standards for new, state-funded housing development projects. At the local level, many municipal governments have broad authority to adopt their own radon control requirements for new home construction.
Following are brief summaries of state policies that establish mandatory minimum radon control standards for new home construction.
Although a number of states have adopted radon control techniques for new home construction, there are more states — including many with high radon potential areas — that can reduce exposure to radon by enacting such policies. Watch for updates to this page as new policies are enacted.
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