T. Mustard, Parsons, Denver, CO; A. Soque, City and County of Denver, Denver, CO.
During the early 1900s, Denver, Colo., was home to a radium processing industry. The production process created waste “tailings,” which were left in large piles near the processing plants. In the 1920s, radium processing was discontinued and the tailings piles were abandoned. Over the years some of these piles were used as fill and aggregate in street construction. In the late 1970s, the U.S. Environmental Protection Agency identified several Denver streets that had been constructed using the radioactive tailings. Denver’s Radium Streets Project is comprised of nine street segments totaling approximately 22 city blocks that contain low-level radioactive contamination in residential areas near downtown Denver.
The contaminants primarily consist of natural radium, thorium, uranium, and associated daughter products including radon gas. The contamination associated with these streets is bound in the asphalt and poses a minimal threat to nearby residents. It is a concern, however, to city workers and contractors who must excavate the streets for underground utility projects.
The first phase of demolition and reconstruction of two of the street segments (totaling 10 blocks) was initiated in 2003. The project involved the removal of radium-contaminated asphalt, curbs, and gutters; removal of manholes and storm drains; and the removal of up to two inches of subgrade below all radium-contaminated paving. The excavated contaminated material was containerized and transported via trucks and rail cars to a licensed disposal site in Idaho. The project work also included air monitoring, soil sampling, site monitoring, site security, traffic controls, installing barrier fence, surveying, and repaving.
Protection of neighborhood residents as well as site workers was a primary concern during this project. This paper describes the safety procedures implemented to protect the site workers and nearby residents during street demolition and reconstruction.
C. Duffield, U.S. Geological Survey, Reston, VA.
The Nuclear Regulatory Commission and the Occupational Safety and Health Administration Training require employers to train employees who are occupationally exposed to ionizing radiation. The U.S. Geological Survey and the Department of the Interior University developed interactive web-based training as a cost-effective method of providing training for a variety of ionizing radiation users in many locations. Employees take a basic module and one to four additional modules in X-ray machines, naturally occurring radioactive materials, general licensed materials, or specific licensed materials. The program tracks performance and maintains the training records.
O. Azpuru, Boston University, Boston, MA.
Situation: In April 2002, the Boston University Office of Environmental Health and Safety (OEHS) received a call from the BU Occupational Health Center alleging that several members of the women’s volleyball team had developed redness and irritation on their face, eyes, and upper shoulder area after practicing in an indoor gymnasium. Upon further investigation, OEHS determined that members of other sports teams had also experienced these symptoms after spending time in this gymnasium; the Fencing Team did not seem affected. All equipment was kept in a common storage room and was routinely cleaned using a “scrub-free” cleanser. The teams were advised to stop using this cleanser.
Suspecting contact dermatitis, OEHS observed a full practice of the women’s volleyball team in an attempt to identify the cause. No cause was found that day; however, redness and irritation were observed on several team members. Samples were collected for bioaerosols, total dust, VOCs, etc; all were inconclusive. Non-chemical/biological causes began to be explored, including the gymnasium lighting.
Problem: The culprit was found to be a single mercury-vapor lamp that had been damaged by direct impact. This lamp has an inner arc tube which continues to function after the outer glass envelope has shattered; the arc tube produces extremely high levels of UV radiation (measured to be much greater than ACGIH TLV® at ground level). The lamp fixture was missing both a protective safety cage and a glass lens.
Resolution:
Benefit to Others:
J. Franks, U.S. Army CHPPM, Aberdeen Proving Ground, MD.
LASIK is a common technique for improving myopic vision using an excimer laser to remove underlying corneal tissue. During the procedure, operating room personnel may be exposed to scattered actinic ultraviolet radiation. The necessity for laser eye protection has been questioned by user personnel because the scattered UV levels are assumed to be very low levels. Little guidance is available from the current ANSI Z136.3 Standard for the Safe Use of Lasers in the Health-care Environment. This paper describes radiometric measurements that were made during LASIK procedures using an excimer laser operating at a wavelength of 193 nm. These measurements were then evaluated using a worst-case procedure and then compared to the ACGIH TLV®s to perform a risk/hazard analysis. It was concluded that eye protection is not necessary to protect operating room personnel since exposure levels are very low even under a worst-case scenario.
F. Akbar-Khanzadeh, J. Loring, Medical College of Ohio, Toledo, OH.
Daytime ultraviolet radiation (UVR) is among the numerous occupational health hazards to which employees onboard marine vessels are potentially exposed. To determine the extent of exposure, a UV radiometer (International Light Inc., Model IL1400A) connected to one of three detectors of UV-A (Model SEL033), UV-B (Model SEL 240), and UV-C (Model 240) was used to measure UVR levels on 12 marine vessels 21–87 ft in late February in Louisiana. The irradiance (µW/cm2) of: (1) UV-A ranged from 1470–2880 with a mean (SD) of 2075 (434); (2) UV-B ranged from 3.8–20 with a mean (SD) of 11 (5.1); and (3) UV-C ranged from 27–61 with a mean (SD) of 47 (11). A total of 441 workers (408 males, 33 females) were potentially exposed to these UV levels from a few minutes to a few hours per day. Compared to current guidelines, these results suggest that workers onboard marine vessels have the potential for UVR overexposure.
M. Shum, M. Kelsh, Exponent Inc., Menlo Park, CA; A. Sheppard, Asher Sheppard Consulting, Redlands, CA; N. Kuster, IT’IS, Zurich, Switzerland.
Our research addresses the need to improve understanding of exposure to radiofrequency (RF) energy among users of mobile phones. Better exposure assessment is critical to any future epidemiologic studies and can help analyze those completed and now underway. We identify the features of cell phones, cell phone systems, and their manner of use that can be used as markers for individual RF exposure. We have assumed that the ideal individual exposure information would be a continuous record of RF energy absorbed at specific sites in the body over a lifetime of cell phone use. We have conducted pilot testing to determine the importance of the following exposure predictors: (1) phone type, terrain, time of call, network, and population densities; (2) technical features of wireless technology and personal attributes such as age, gender, and income; and (3) personal habits such as the hand used to hold the phone and use of hands-free devices. In addition, we have initiated a study involving a comparison of questionnaire-reported cell phone usage to billing records and data from study participants using modified phones that record output power settings (“dose-phones”). This presentation summarizes the data accumulated to date and outlines future work that will be conducted.
A. Krake, B. King, NIOSH, Cincinnati, OH.
Heat stress evaluations were conducted at seven southern/southwestern U.S. Air Force (USAF) bases as part of a collaborative study of USAF employees’ acute exposure to jet fuel. USAF recruits employed as aircraft fuel systems maintenance inspection and repair workers were exposed to hot working conditions in confined spaces (aircraft fuel tanks) while wearing PPE. The potential for developing heat strain prompted USAF health and safety managers to request a heat stress evaluation. NIOSH investigators evaluated heat stress and strain using swallowable core body temperature (CBT) sensors, external heart rate (HR) monitors, and wet bulb globe temperature (WBGT) monitors. Pre- and post-shift body weight comparisons were also made on 50% of the employees. Job activities were analyzed according to metabolic heat production estimates. ACGIH suggests a maximum CBT of 101.3°F for medically selected, acclimatized personnel and 100.4°F for unselected, unacclimatized personnel. For individuals with normal cardiac performance, sustained HR (over several minutes) should not exceed 180 beats per minute minus age. And, because there is a greater risk of heat strain if profuse sweating is sustained over hours, weight loss over a shift should not exceed 1.5% of body weight. NIOSH work/rest regimen tables were used to plot the estimated metabolic heat against the environmental heat measurements. WBGT temperatures at all locations ranged from 53–93°F outdoors and from 60–88°F indoors and indicated that employees were exposed to heat stress conditions in excess of the NIOSH and ACGIH screening criteria for acclimatized individuals. Physiological sampling results indicated that about 25% of the study participants experienced heat strain signs (HR and/or CBT in excess of ACGIH criteria), and that 62% of those weighed developed at least mild dehydration during their activities. Recommendations were made to develop physiological monitoring programs and heat stress management and illness surveillance systems.
R. Anderson, D. MacQueen, G. Laguna, Lawrence Livermore National Laboratory, Livermore, CA.
Managers, supervisors, industrial hygienists, and health and safety technicians were seeking information that would help them to predict each day whether heat stress might become an issue, and if so, when. Users also desired clear work rest regimen decision points that would incorporate clothing and work rate changes without having to perform field calculations. “Heat Wave,” a web-based heat stress management tool was created to meet these needs. The tool uses a simple model to estimate WBGT-°C from current local meteorological data. The model, statistically validated against empirical data, yielded the central 95% of data points within +/- 1.15 WBGT-°C and a multiple R-squared of 0.97. The “Estimator” section of the tool combines menu-chosen operational information provided by users (clothing ensemble, work rate, and acclimatization level) and ACGIH TLV® heat stress screening criteria to determine the WBGT-°C trigger point for initiating a work rest regimen. The WBGT-°C trigger point is then compared to modeled data. If a work rest regimen is currently needed, the time and ambient air temperature when it began is displayed. If the trigger point has not been reached, users are invited to “estimate” the time this will occur today using data from the previous five days. Today’s forecasted high temperature is also displayed. Other “Heat Wave” tools include user-specific WBGT Meter Reading vs. Work Rest Regimen Tables. Users can easily create and print tables reflecting various clothing and work rate combinations. This enables users to deploy controls without depleting IH resources. The tool also hosts a “Tailgate” presentation on heat stress management and provides links to other heat stress resources.
This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. UCRL-ABS-200145
Posted May 30, 2004