152
MISAPPLICATION OF EMERGENCY EXPOSURE LIMITS.
J. Morawetz, ICWUC Center for Worker H&S Education, Cincinnati, OH.
Since 2000, the National Advisory Committee for Acute Exposure Guideline Levels (AEGLs) has published recommended values for 22 chemicals. These are intended as once-in-a-lifetime emergency exposures to the public and thresholds for three health endpoints: AEGL-1, AEGL-2, and AEGL-3. They are developed for exposures from 10 minutes to eight hours, with increasing toxic effects from symptoms to lethality. A number of organizations are using AEGLs with questionable appropriateness that should be openly discussed and evaluated.
The Environmental Protection Agency (EPA) includes 10-minute AEGLs in their ALOHA plume mapping program. ALOHA also includes 15-minute Temporary Emergency Exposure Limits and AIHA’s 60-minute Emergency Response Planning Guidelines values with little explanation on the need to match the exposure period to the value’s defined time period. In the National Emission Standards for Hazardous Air Pollutants, the EPA used AEGL values for acute risk assessment that compares modeled maximum facility emissions to AEGL values. This is not the AEGL’s intended once-in-a-lifetime exposure and ignores repeated exposures both before and after a maximum emission.
In the license application for Fuel Cycle Facilities, the Nuclear Regulatory Agency requests applicants to perform a risk analysis for the community and workers. They inappropriately apply AEGLs in an occupational context from “not unlikely” events (up to AEGL-2 levels) to “extremely unlikely” events (above AEGL-3 values). Most troubling is the implication that worker exposures can regularly be up to AEGL-2 values, regardless of the mandated OSHA standards. Policy paper number 20 of the Chemical Stockpile Emergency Preparedness Program (jointly issued by the Army and Federal Emergency Management Agency) addresses the health effects of nerve agents above each AEGL value. Their broad statements on AEGLs minimize the expected health outcomes that, unless amended significantly, reduce the potential health risk for other substances.
153
EXPERIENCE WITH DEPARTMENT OF JUSTICE THREAT AND RISK ASSESSMENT ON A MEDICAL
CAMPUS.
M. Kendig, R. Vetter, Mayo Clinic, Rochester, MN.
The Department of Justice developed a tool for the assessment of threats and risks associated with potential targets involving a variety of civilian activities. The tool could be used to evaluate a variety of targets including city utilities, transportation, special events, and institutions including research facilities and hospitals. We used this tool to evaluate threats and risks to an academic medical center that utilizes a variety of chemicals, biological agents, and radiation sources. The risk assessment was intended to supplement, not replace, the vulnerability analysis required by the Joint Commission of Accreditation of Healthcare Organizations. The risk assessment was conducted in conjunction with a risk assessment of other potential vulnerabilities including utilities, building ventilation systems, building entrances, emergency department, and others. The risk assessment team included representatives of the medical center as well as members of local law enforcement, local fire department, and emergency medical services. Since many terrorists employ “opportunistic” tactics, we focused on materials which were already present in the community. The team concluded that the vulnerability due to the chemical, biological, and radiological agents was low compared to the other potential targets. The team also concluded that the most vulnerable time for a potential terrorist act involving radiological sources in medicine or research was at the time of delivery of the source, chemicals it was the large storage sites, but biological agents were very secure in restricted access laboratories.
154
DEVELOPMENT OF TOLUENE AND XYLENE ACUTE EXPOSURE GUIDELINE LEVELS (AEGLS) USING
PBPK MODELING.
J. Dennison, Colorado State University, Ft. Collins, CO; C. Troxel, CMTox Inc., Lander, WY; S. Talmage, Oak Ridge National Laboratory, Oak Ridge, TN; M. King, U.S. EPA/OPPT, Washington, DC.
AEGLs are guidelines set by USEPA for community exposure during emergencies, such as chemical spills, for three levels of toxicity: discomfort, disabling effects, and death. AEGLs are derived for 10- and 30-minute and one-, four-, and eight-hour exposure durations to meet a wide range of needs for government and private organizations. In general, sparse toxicity data are available, including very limited human data. For example, LC50 data used to set the AEGL for death (AEGL-3) may only be available for a four-hour exposure. Thus, considerable difficulties exist in setting AEGLs and require extrapolation from animal to human and across time. Furthermore, humans may be physically exerting during emergencies, while animals are resting during experiments. We used physiologically-based pharmacokinetic (PBPK) models for toluene and xylene to perform extrapolations and to explicitly incorporate the effects of exercise, which affects solvent uptake. Models were validated with blood and exhaled breath data for rats or humans at rest and exercising. AEGL values were calculated by (1) determining the blood level in rats at the point of departure for the AEGL-1, -2, or -3; (2) calculating the equivalent human exposure that resulted in the same blood level during human exposure for the 10- and 30-minute and one-, four-, and eight-hour AEGLs; and (3) applying an intraspecies UF for human variability. During exercise, significantly higher blood levels of both chemicals occurred, indicating that AEGLs based on resting conditions are not protective. However, humans have lower blood levels of toluene and xylene than rats, so when exercise is not considered, higher exposures could be permitted. The PBPK models greatly improve the extrapolations made when setting AEGLs, and therefore reduce the uncertainty in the guidelines. [This abstract presents interim AEGL values that are subject to change pending further review by NAS.]
155
CHRYSOTILE, NANOPARTICLES, AND RISK OF MESOTHELIOMA.
C. Yarborough, Exponent Inc., New York, NY.
Thousands of people were exposed to short fibers of asbestos and other respirable materials less than 2.5 microns in diameter (including nanoparticles) following the World Trade Center attacks in 2001. Among the issues to be resolved regarding respiratory exposures is the potential risk of mesothelioma from exposure to chrysotile fibers. Although epidemiologic studies find mesotheliomas associated with exposure to amphibole asbestos fibers, a causal link between chrysotile and mesothelioma has been debated for decades. I undertook a comprehensive review of the world’s literature to assess exposures, enumerate cases, and focus on whether replication of studies, a key step of the scientific method, would support an epidemiologic association. The analysis of studies, including 158,000 workers in over 50 cohorts, does not support the hypothesis that exposure to pure chrysotile fibers causes mesothelioma. Mesothelioma cases are associated with exposure to amphibole but not chrysotile exposures in these cohorts. Regulatory decisions about risk of chrysotile reflect public risk management policies. In this case, such policies are not supported by the identification of a significant health hazard as determined by application of the scientific method as applied to epidemiologic studies and other relevant industrial hygiene, toxicologic, and medical data. Understanding of any health risks associated with exposure to chrysotile is crucial for assessing risks of accidental and process- or product-related exposures to fibers ranging in size from fine particles to nanofibers. Risk management decisions would be improved by more targeted research for populations exposed to natural and synthesized respirable particles.
156
EFFECTS OF STYRENE ON NEUROTOXICITY.
B. Li, National Institute for Occupational Health and Poison Control, Chinese CDC, Xuanwu District, Beijing, China.
Sprague-Dawley rats were exposed to styrene acutely and subacutely, in order to examine the effect of duration and dosage of exposure on the nervous system. Based on the changes of behavior as exterior markers of styrene neurotoxicity and urinary metabolites mandelic acid (MA) and phenylglyoxylic acid as inner dosage, the effects of styrene on levels of dopamine (DA) were detected, the activity of monoamine oxidase (MAO) was elevated.
Density and affinity of dopamine receptor1 (DR1) in retina, dopamine receptor2 (DR2) in hypophysis, and dopamine receptor3 (DR3) in striatum were measured. The effects of three weeks of recovery and L-dopa were observed so as to prevent and cure styrene neurotoxicity.
Styrene exposure reduced times of horizontal and vertical movements significantly and falsity times rose significantly compared with control. Styrene decreased the levels of DA, increased the activity of MAO in hypophysis, and reduced in retina and striatum. Levels of MA and PGA were associated with dosage positively, and MA may be more sensitive as an inner dosage. Styrene reduced the density of DR1 and DR3, and enhanced the density of DR2. For DR1 and DR2, recovery may be more efficient than L-dopa in the recovery of density. L-dopa was more active for DR3. The affinity of female rats was higher than in males. Styrene decreased the affinity of DR1 and DR3, and upgraded DR2. Recovery promoted affinity of DR to normal levels, whereas L-dopa only recovered the affinity of DR1 in male rats and DR2 and DR3 in female rats compared with control.
The result implicated that the depletion of DA and the changes of density and affinity of DR in rats exposed to styrene may effect the function of the dopaminergic system in the central nervous system, which was representative by the symptoms of obstacle of motor function and loss of learning and memory.
157
COST ANALYSIS OF WORK ACCIDENTS IN A TIRE PRODUCTION COMPANY.
A. Miguel, University of Minho, Guimaraes, Portugal; F. Campelo, SMGP–Consultores, Porto, Portugal.
The present study aims at developing a methodology of economic analysis of work accidents in a large tire production company.
For the development of this methodology, it was necessary to define the variables and the relevant costs. Due to the general aspect of the methodology, little adjustments had to be made regarding the gathering of the several variable costs that are described through this document. Nevertheless, 70% of the actual costs are expected to be included in the economical analysis.
The global cost of accidents was analyzed according the variability, imputability, and responsibility. It was possible to obtain the additional cost due to the occurrence of a new accident, the amount of costs assumed by the company, and the unit costs’ value according to the lesion type and the affected part of the body.
The relationship between both insured and not insured costs, i.e., the costs for which the company is responsible and the ones transferred for the insurance corporation, was in this case equal to 1:3.3. A value of 619,607.65 € was assumed by the insurance entity and a value of 2,021,086.76 € was assumed by the company from 1997 to 2001. More than the economical analysis of the case under appreciation, the work aims at motivating the managers to the issues of accident costs in order to adopt a similar methodology to that developed from this case.
158
SAFE USE AND GUARDING OF MAINTENANCE SHOP MACHINES.
S. Vogl, L. Schumann, Clayton Group Services Inc., Edison, NJ.
OSHA Directive CPL 2-1.35 outlines a National Emphasis Program on Amputations. Besides specifically mentioning amputations caused by saws, the directive allows for application of the national emphasis program to other machinery, listed in an appendix to the directive, so long as the regional or area office of OSHA applying the program has established a local emphasis program for such machinery. Machines mentioned in the appendix include boring, drilling, milling, and planing machinery, as well as grinding and polishing machinery. These types of machines, including saws, are typical of most industrial maintenance shops. In addition, tools such as lathes and sanders, though not addressed in the OSHA directive, are often found in maintenance shop environments.
This presentation will focus on the safe use and appropriate guarding of typical maintenance shop machinery. Machines discussed will include drill presses, milling machines, table saws, band saws, radial saws, lathes, sanders, and grinding wheels. The session will address required, as well as accepted, practices for the safe use and guarding of maintenance machines. Points of operation as well as other hazard points, such as power transmission, will be discussed. The presentation is designed to provide the industrial hygienist with a basic overview of the hazards and hazard points associated with several typical maintenance shop machines and to provide guidance on appropriate guarding for such machines.
Posted May 30, 2005