As a result of this intentional release of B. anthracis, several post offices,
mailrooms in government buildings, and private office buildings were contaminated with B.anthracis spores. During the initial response, frequent requests were made for published materials about inactivating Bacillus spores.
However, no adequate single source of literature on this subject was available. Because of the risk to humans, remediation of anthrax-contaminated buildings and their contents has been the focus both of scientific discussion and commercial product marketing. A number of manufacturers
have developed equipment or materials that reportedly kill B. anthracis spores. However, these manufacturers have tested their products with laboratory tests that use
Bacillus species other than B. anthracis, and the efficacy of some of these technologies relies on published literature. An obvious concern is whether postremediation levels of
spores are safe; the summarized studies make no claim about whether a safe level exists and what it might be. We provide a summary of much of the available literature on the inactivation of Bacillus spores that is relevant to the inactivation of B. anthracis. We reviewed publications
from 1930 to 2002, and we have created a tabular
summary of those articles. Treatments or agents commonly
cited include heat, formaldehyde, hypochlorite solutions, chlorine dioxide, and radiation. Methods regarding inoculum size, concentration, and other variables are not consistent between experiments, but each experiment provides some specific information of value. Early studies
that lack quantitative data are not included. A number of the cited studies address Bacillus species other than B. anthracis. We include these for information, with the
caveat that surrogates do not always predict the behavior
of the target species. Furthermore, the results from laboratory
experiments do not specifically address questions
regarding the best methods for inactivating spores on different
materials such as mail, carpet, other porous objects,food, or water. Transfer of these sporicidal methods from the laboratory to a building has not yet been tested; however,the known laboratory results are a logical place to start when considering the decontamination of a building. Decontamination is defined as the irreversible inactivation
of infectious agents so that an area is rendered safe.However, decontamination may not eliminate bacterial spores. Sterilization is the complete destruction or elimination
of microbial viability, including spores (3). The experiments described provide a logical starting point for future experiments and decontamination strategies in the event of anthrax bioterrorism. Our intent is not to provide a comparative evaluation or recommendations
for decontamination but rather to summarize the quantitative published results and provide a useful reference.