W. Adkins, B. Gordon, Oklahoma Medical Research Foundation, Oklahoma City, OK; R. Lynch, R. Clinkenbeard, M. Phillips, University of Oklahoma, Oklahoma City, OK.
Approximately 90,000 laboratory animal care workers are employed in the United States. Over a working lifetime, 21% will become sensitized to laboratory animal allergen (LAA), and 2000 will develop occupational asthma. The purpose of this study was to determine the amount of allergen that animal care staff at a biomedical research laboratory was exposed to during performance of daily duties. A range-finding pilot study was conducted using area samples, followed by a personal exposure study using both personal and area samples. In both studies, full-shift dust samples were collected on closed-face cassettes. LAA was detected and quantified using commercial enzyme linked immunoassay (ELISA) kits for the allergen MusM1. Approximately 86% of samples (154/189) in both the pilot study and the personal exposure study were below the limit of detection (LOD), which ranged from 0.06-1.2 ng per ELISA well. Pilot study area samples ranged from detection limit to 9.4 µg. In the personal exposure study, the worst-case exposure was assumed to occur while changing cages without benefit of local exhaust ventilation. Under these conditions, 16% of personal samples (3/18; range: 4.75-16.00 ng/M3) were positive for allergen for one individual. The range of detectable personal exposure under normal duties in ventilation-controlled conditions was 5.96-22.92 ng/M3, with one technician being responsible for most of the results above LOD. Pilot study results suggest that animal care technicians were exposed to LAA with exposures to technicians under regular conditions. Currently no occupational guidelines exist for airborne exposure to LAA. Ventilation controls in the study facility already surpass National Research Council guidelines. Additional work practice controls are recommended.
J. Schaefer, R. Hamilton, Johns Hopkins University, Baltimore, MD.
A NIOSH alert on preventing asthma in animal workers reported that 25% of all animal workers will develop allergies to animals and 10% will develop occupational asthma. The alert detailed actions to be taken to minimize the risk of developing allergies, but no guidelines were given as to levels of airborne concentration that would minimize the potential for developing inhalation allergies. A review of the literature provided some information as to levels likely to cause allergic sensitization. A study was conducted of airborne concentration generated by mice in differing housing arrangements and worker exposure due to assigned duties. A recommendation of exposure levels was generated and animal handlers were monitored to determine airborne exposure relative to the recommendations. Evaluation of the effectiveness of engineering controls in preventing the need for respiratory protection for animal workers.
S. Magari, Colden Corp., East Syracuse, NY; G. Richey, Colden Corp., Philadelphia, PA.
The challenges of decommissioning research laboratory space are myriad. Over the years, mercury has been one of the most complex issues we continue to encounter working in both academic and industrial research laboratories. Even though superficial visual reviews and real-time monitoring may indicate a laboratory free from mercury, once the demolition begins, additional mercury hazards are uncovered. The project management workflow proves critical for safe and successful work completion, particularly when faced with other common hazards such as radiation and asbestos. Recent case reviews will be presented that illustrate the need to tailor the decommissioning plan to the renovation scope and to include environmental health and safety professionals in the design stages of a renovation project. The applicability and the pros and cons of various sampling strategies, including real-time area mercury vapor monitoring and personal and area air sampling, will be covered as well as bulk and wipe sampling.
Q. Danyluk, Fraser Health, New Westminster, BC, Canada; C. Hon, Vancouver Coastal Health, Vancouver, BC, Canada.
One method of establishing exposure levels resulting from a chemical spill is to use mathematical exposure models. However, the applicability of these models to conditions of interest is uncertain, as the predicted results have not been validated with those values obtained from real-time exposure monitoring of a spill. Exposure models typically involve a generation component and a dispersion component. The objectives of our study were to evaluate the accuracy of (1) selected models at estimating the generation rate of vapors resulting from simulated spills, and (2) selected dispersion models at estimating the potential exposures to staff resulting from varying spill sizes of chemicals over time. Five different models were selected to estimate the vapor generation rate, and three different models were selected to estimate the vapor dispersion rate from spilled liquids. Six organic substances commonly found in the health care setting were selected to test these models. For each chemical, simulated spills were conducted involving multiple trials of four different volumes. For each simulated spill, the generation rates and airborne exposure levels were measured and logged at 30-sec intervals using real-time instrumentation. Through the creation of detailed spreadsheets and graphs, the mathematical model predictions were compared to the measured data. A review of the generation rate data indicates that, in all instances, the measured generation rates were well in excess of the generation rates predicted by the models examined in our study. Conversely, the majority of the dispersion rate models were found to severely overpredict the dispersion levels measured. Although our results are quite preliminary and rather limited in scope, we believe these mathematical models do hold promise and that the reported work should be expanded, as the results of our study are likely to be of interest to occupational hygienists and emergency spill response personnel.
Q. Danyluk, Fraser Health, New Westminster, BC, Canada.
Formalin is one of the most common chemical products used within a health care setting and can be found in numerous departments including anatomical pathology, histology, and operating rooms. Because of the frequency and volume of use, formalin spills are quite common occurrences. A large variety of spill control products are available for dealing with formalin spills. These products include neutralizing liquids, powders, and absorbent pads. In most health care institutions, products are traditionally purchased and used based on manufacturers claims, historical use, and cost. In order to achieve an effective spill control program, one must be familiar with the effectiveness and limitations of these products to ensure that the most appropriate product is employed. Our research involved conducting multiple simulated formalin spills and measuring the resulting airborne concentration levels. Subsequently, a number of commercially available formalin spill control products were examined to determine their effectiveness at cleaning up the spill and reducing the airborne concentration levels in a timely manner. The products tested demonstrated a wide range of effectiveness. Our findings suggest that for the most effective cleanup with the quickest decrease in airborne concentration, the use of an absorbent pad is recommended. The results of this study have been used to create detailed, evidence-based formalin spill procedures for our organization. Additional studies may focus on different sized spill volumes, other chemical products, and different spill control products.
C. Hon, Vancouver Coastal Health, Vancouver, BC, Canada; Q. Danyluk, Fraser Health, Vancouver, BC, Canada.
A large number of chemical products are used within laboratories, and spills can be a common occurrence. Workers who are called upon to perform chemical spill cleanup must be adequately protected. In order to determine the appropriate protective equipment to be worn, a risk assessment should be performed to ascertain the level of risk posed by the chemical hazard.
There are four methods for performing such risk assessments: (1) assume worst-case exposure, (2) measure the exposure level at the time of the spill, (3) calculate exposure levels a priori using mathematical exposure models, and (4) conduct simulated spills, measuring the resulting airborne concentration levels. To construct an effective spill control program, one must be familiar with each of these four methods and their application. Our discussion will focus on the advantages and limitations of each method from a practical industrial hygiene perspective. Assuming worst-case exposure may lead to providing unnecessary and cumbersome personal protective equipment; in turn, this could result in additional health and safety concerns. Measuring the exposure level at the time of the spill is generally not practical because of time constraints, instrument availability, and cost factors. The majority of published mathematical exposure models have not been validated for most conditions of interest and can be difficult as well as laborious to work with. Lastly, conducting simulated spills requires a high level of knowledge, specialized equipment, and defined, user-controlled conditions. In addition, it is extremely time-consuming.