Academic journal article Environmental Health Perspectives

Mold and Endotoxin Levels in the Aftermath of Hurricane Katrina: A Pilot Project of Homes in New Orleans Undergoing Renovation

Academic journal article Environmental Health Perspectives

Mold and Endotoxin Levels in the Aftermath of Hurricane Katrina: A Pilot Project of Homes in New Orleans Undergoing Renovation

Article excerpt

BACKGROUND: After Hurricane Katrina, many New Orleans homes remained flooded for weeks, promoting heavy microbial growth.

OBJECTIVES: A small demonstration project was conducted November 2005-January 2006 aiming to recommend safe remediation techniques and safe levels of worker protection, and to characterize airborne mold and endotoxin throughout cleanup.

METHODS: Three houses with floodwater lines between 0.3 and 2 m underwent intervention, including disposal of damaged furnishings and drywall, cleaning surfaces, drying remaining structure, and treatment with a biostatic agent. We measured indoor and outdoor bioaerosols before, during, and after intervention. Samples were analyzed for fungi [culture, spore analysis, polymerase chain reaction (PCR)] and endotoxin. In one house, real-time particle counts were also assessed, and respirator-efficiency testing was performed to establish workplace protection factors (WPF).

RESULTS: At baseline, culturable mold ranged from 22,000 to 515,000 colony-forming units/[m.sup.3], spore counts ranged from 82,000 to 630,000 spores/[m.sup.3], and endotoxin ranged from 17 to 139 endotoxin units/[m.sup.3]. Culture, spore analysis, and PCR indicated that Penicillium, Aspergillus, and Paecilomyces predominated. After intervention, levels of mold and endotoxin were generally lower (sometimes, orders of magnitude). The average WPF against fungal spores for elastomeric respirators was higher than for the N-95 respirators.

CONCLUSIONS: During baseline and intervention, mold and endotoxin levels were similar to those found in agricultural environments. We strongly recommend that those entering, cleaning, and repairing flood-damaged homes wear respirators at least as protective as elastomeric respirators. Recommendations based on this demonstration will benefit those involved in the current cleanup activities and will inform efforts to respond to future disasters.

KEY WORDS: endotoxin, flood, fungi, mold, Hurricane Katrina, New Orleans, remediation, respirators. Environ Health Perspect 114:1883-1889 (2006). doi:10.1289/ehp.9258 available via [Online 24 August 2006]


Hurricane Katrina, which occurred on 29 August 2005, caused the breach of several levees surrounding New Orleans, Louisiana, and left over 75% of the city underwater. A storm surge from Hurricane Rita several weeks later reflooded many areas of the city. In the aftermath of these disasters, homes were submerged in flood water for several summer weeks, resulting in severe mold and bacterial growth, both of which can lead to a panoply of respiratory health effects [Institute of Medicine (IOM) 2004]. Although several studies have assessed markers of mold and bacteria in damp and water-damaged homes (IOM 2004), there is a dearth of literature documenting the levels of these agents in homes that received sustained flooding (Ross et al. 2000).

New Orleans and the surrounding communities currently face difficult decisions regarding whether or not to demolish large numbers of damaged homes. Many factors will be taken into consideration when those decisions are made, including the question of whether mold and bacteria can be safely and affordably removed from the flooded homes prior to building restoration. On 27 October 2005, the National Center for Healthy Housing (NCHH) convened a meeting to examine options for flood cleanup procedures and air sampling. Attendees included building materials scientists, mold remediation experts, members of community-based organizations, industrial hygienists, clinicians, housing policy makers, and environmental epidemiologists from across the country (including areas affected by Hurricane Katrina). The attendees drew on a body of guidance documents for flood cleanup and mold remediation [American Red Cross and Federal Emergency Management Agency 1992; Centers for Disease Control and Prevention (CDC) 2005; Louisiana State University 2005; New York City Department of Health and Mental Hygiene 2002; U. …

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