Positive pressure suits are widely used at BSL-4 to protect operators from contact with microbiological agents. As there is the potential for the outside of the suits to become contaminated during use, they must be decontaminated prior to final exit from the high-containment laboratory. Chemical showers are used to remove biological material from suits, and the shower effluent is collected for subsequent treatment by heat or chemicals. The efficacy of showering to clean/remove biological materials from two different BSL-4 suits (ILC Dover and Delta) was studied using Bacillus atrophaeus spores dried directly onto the suit surface as a surrogate contaminant, with a 4 log colony forming unit (cfu) reduction pass criterion required. Initial studies using water alone, without disinfectant, achieved a 1-2 log cfu reduction in the microbial contamination. However, direct scrubbing, using a lightweight brush combined with relatively short cycle times (6 minutes) and low water volumes (<45 L per cycle) achieved an average spore reduction of 3.4 log cfu from the suit. The log cfu reduction was dependent on suit type, position of the contamination on the suit surface, and suit fit. Higher reductions (mean 4.2 log cfu) were achieved with the ILC Dover suit than the Delta suit (mean 3.6 log cfu) when the tests were undertaken using experienced staff who had been matched to the suit size. The study highlights that assumptions cannot be made about the efficacy of shower decontamination systems for BSL-4 facilities and that familiarization with decontamination improves the efficacy of removal of biological material during showering. Materials and Methods This study measures the effectiveness of biological material removal not disinfection activity and so a resistant, non-pathogenic spore tracer was chosen. Ethics The initial study plan required the use of volunteers and hence the project was submitted to the UK NHS Na

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Concentrations of total rad Sr in milk, January-March 1993. 5.8 Continuous ambient sir monitoring data, 1992 ........ 5.9 Ambient air concentrations of tritium, January-March 1993. . 5.10 Ambient air concentrations of absorbable gases (activated charcoal cartridge filter media) at ORNL air monitoring stations, January-March 1993 ........... 5.11 External gamma radiation measurements at reservation perimeter air monitoring stations, January-March 1993 ...... ix 1. 1.0 INTRODUCTION. The Environmental Surveillance and Protection Section within the Office of Environmental Compliance and Documentation at the Oak Ridge National Laboratory (ORNL) is responsible for the development and implementation of an environmental program to (i) ensure compliance with all federal, state, and Department of Energy (DOE) reporting requirements to quantitatively demonstrate prevention, control, and abatement of environmental pollution;

Concentrations of total rad Sr in milk, April-June 1993 ..... 5.4 Ambient air concentrations of trlti1_m, April-June 1993 ..... 5.5 Ambient air collections of absorbable gases (activated charcoal cartridge filter media) at ORNL air monitoring stations, April-June 1993 .