Interim Findings on Formaldehyde Levels in FEMA-Supplied ...

Interim Findings on Formaldehyde Levels in FEMA-Supplied

Travel Trailers, Park Models, and Mobile Homes

Summary

from the Centers for Disease Control and Prevention February 29, 2008

This interim report of a CDC study provides information about formaldehyde levels in a random sample of FEMA-supplied occupied travel trailers, park models, and mobile homes still being used as of December 2007 and January 2008 as temporary shelter for residents of the U.S. Gulf Coast region displaced by Hurricanes Katrina and Rita. Additional analyses on this study; and additional peer review of the study, its results, and conclusions; are ongoing. A final report on this study will be published in the spring 2008. In addition, other studies related to the health of persons displaced by Hurricanes Katrina and Rita and to formaldehyde levels in travel trailers, park models, and mobile homes are ongoing. However, this interim report suggests that formaldehyde levels in many of the travel trailers, park models, and mobile homes (geometric mean 77 parts per billion [ppb] across all types with many levels higher than this average) are higher than typical U.S. background levels (e.g., approximately 10-30 ppb in indoor air). Therefore, actions should be taken now to limit further exposures to residents. (For specific information, see the report sections below on recommendations to residents and recommendations to public officials).

Interim CDC Findings--Formaldehyde Levels in FEMA-Supplied Travel Trailers, Park Models, and Mobile Homes

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Background From December 21, 2007, to January 23, 2008, the Centers for Disease Control and Prevention (CDC) conducted testing to assess levels of formaldehyde in indoor air of a random sample of occupied travel trailers, park models, and mobile homes supplied by the Federal Emergency Management Agency (FEMA) as temporary housing for residents of the U.S. Gulf Coast region displaced by Hurricanes Katrina and Rita. The testing was one of several actions CDC initiated in response to a request from FEMA on July 13, 2007; to investigate concerns about formaldehyde in occupied FEMA-supplied travel trailers, park models, and mobile homes in Louisiana and Mississippi.

Objectives

The objectives of this study were: 1. To determine formaldehyde levels in occupied travel trailers, park models, and mobile homes. 2. To determine factors or characteristics of occupied travel trailers, park models, and mobile homes that could affect formaldehyde measurements. 3. To provide information to assist FEMA in making decisions about when and how to relocate residents from these FEMA-supplied travel trailers, park models, and mobile homes still used in the Gulf Coast area.

It is also important to understand that this study does not address the following: 1. The results should not be applied to travel trailers, park models, or mobile homes

Interim CDC Findings--Formaldehyde Levels in FEMA-Supplied Travel Trailers, Park Models, and Mobile Homes

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purchased and used in other places and situations because the sample for this study was selected only from FEMA-supplied travel trailers, park models, and mobile homes used in the Gulf Coast region. Other travel trailers, park models, and mobile homes used elsewhere could differ based on their age, the characteristics of their manufacture, the circumstances of their use, or the characteristics of their environment. 2. This is a study of formaldehyde levels, and as such does not assess the health status of persons currently living in FEMA-supplied travel trailers, park models, and mobile homes.

Interim CDC Findings--Formaldehyde Levels in FEMA-Supplied Travel Trailers, Park Models, and Mobile Homes

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Methods

Definitions ? Mobile homes are generally wider than 8 feet and/or longer than 40 feet (for an area greater than 320 square feet). They are built on permanent chassis; contain plumbing, heating, air-conditioning, and electrical systems; and are designed to be used as permanent homes. They are defined and regulated by the U.S. Department of Housing and Urban Development (HUD). ? Travel trailers are wheel-mounted trailers designed to provide temporary living quarters during periods of recreation, camping, or travel. Travel trailers generally have size limits, such as no larger 8 feet in width and 40 feet in length, for an area of less than 320 square feet. Travel trailers are generally considered vehicles rather than structures, and they are regulated by state transportation authorities rather than housing authorities. ? Park models are larger versions of a travel trailers (up to 400 square feet in area), that are used as temporary living quarters. Park Models are manufactured housing which are administratively exempted from HUD construction standards and are therefore typically regulated by transportation authorities and by manufacturer acceptance of a voluntary American National Standards Institute (ANSI) standard applying to their construction.

Selecting the study population and travel trailers, park models, and mobile homes

Interim CDC Findings--Formaldehyde Levels in FEMA-Supplied Travel Trailers, Park Models, and Mobile Homes

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CDC randomly selected 519 travel trailers, park models, and mobile homes for testing using a FEMA-provided list of the 46,970 occupied travel trailers, park models, and mobile homes in Mississippi and Louisiana as of November 2007. The number of travel trailers, park models, and mobile homes chosen to be studied was based on power calculations designed to allow researchers to draw statistically valid conclusions for the population being studied (i.e., FEMA-supplied travel trailers, park models, and mobile homes being used in the Gulf Coast region) and for common types of travel trailers, park models, and mobile homes within that population of FEMA-supplied travel trailers, park models, and mobile homes. Disproportionate stratified random sampling was used to select travel trailers, park models, and mobile homes for testing.

The travel trailers, park models, and mobile homes were divided into 11 strata defined by the type of unit most commonly used: travel trailer, mobile home, and park model. The travel-trailer type was divided into seven strata defined by the top six brands1 (Gulfstream, Forest River, Fleetwood, Fleetwood CA, Pilgrim, and Keystone) that together represented 61% of the occupied travel trailers, park models, and mobile homes being used. The seventh travel-trailer stratum included a combination of all other traveltrailer brands supplied by FEMA. The park-model type had two strata: the most common brand, Silver Creek, that represented 21% of the park models being used, and all other park model brands. The mobile-home type also was divided into two strata: the most common brand, Cavalier, that represented 17% of the mobile homes being used, and all

1 Note: some brands may be made by more than one manufacturer

Interim CDC Findings--Formaldehyde Levels in FEMA-Supplied Travel Trailers, Park Models, and Mobile Homes

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