ATSDR EXPOSURE INVESTIGATIONS IN THE COMMUNITY. P. Kowalski, J. Abraham, S. Metcalf, Agency for Toxic Substances and Disease Registry, Atlanta, GA
The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agency within the Department of Health and Human Services. ATSDR’s mission is to prevent exposure and adverse human health effects and diminished quality of life associated with exposure to hazardous substances from waste sites, unplanned releases, and other sources of pollution.
The Division of Health Assessment and Consultation (DHAC) prepares public health assessments (PHAs) to determine whether hazardous substances may result in exposure and whether exposure might cause any harm to people. ATSDR conducts a PHA for every site on or proposed for the National Priorities List. If exposure information is insufficient, ATSDR may conduct an exposure investigation to better characterize exposure to hazardous substances and to evaluate possible health effects related to those exposures.
A team of toxicologists, physicians, and environmental health scientists develops an appropriate protocol to determine whether a completed exposure pathway exists. Exposure investigations are initiated if the following criteria are met: 1) an exposed population has been identified; 2) additional information on the exposure is required to evaluate the site; 3) the exposure investigation will provide that information; and 4) results of the investigation will affect public health decisions.
ATSDR uses environmental sampling, testing for biological markers of exposure, and computer modeling to conduct exposure investigations. These exposure investigations allow ATSDR health assessors to better characterize exposure in a timely manner. Exposure investigations are limited in that they characterize recent exposure better than past exposure and that documenting exposure is not synonymous with a health effect.
ENVIRONMENTAL SAFETY, AND HEALTH PREVENTION IN THE RESIDENTIAL COLLECTION OF MUNICIPAL SOLID WASTE. L. Andrew, EnvirOSH Services, Inc., Tomball, TX
Preventive control measures can be implemented to control environmental safety and health (ESH) hazards associated with residential collection of municipal solid waste. Municipal solid waste collection workers are exposed to chemical, physical, and biological hazards. The Bureau of Labor Statistics reported that refuse collectors have the seventh most dangerous job in the nation; from 1992 to 1996, 111 garbage collectors were killed. This is a challenging environment for regulators and ESH professionals because this activity blends transportation, workplace safety, mobile petroleum storage tanks, and many other hazards that coincide with OSHA, DOT, EPA, and numerous other state and local regulatory agencies.
Approximately 4.35 pounds of trash are generated per person per day in the United Sates. The results of an ergonomics study conducted by a Fortune 250 waste services company shows a typical collection worker, performing backdoor service, lifting 13,000 pounds of trash, while jogging 13 miles a day. Examining the company’s risk management database shows 42% of the workers’ compensation cases were sprains and strains (mostly low back) and account for 53% of the compensation costs. Preventive measures such as initial physical conditioning of the worker and personal back care are needed to control back strains and sprains.
Homeowners may throw out full containers of hazardous chemicals that collection workers inhale or come into direct contact with, causing serious health effects. Prevention programs include household hazardous waste “roundup” days, community education programs, and training refuse workers on the signs and symptoms of hazardous chemical exposures. Hydraulic fluid releases create environmental issues that can be reduced with new low pressure sensing technology and quick worker spill response training.
In conclusion, this will continue to be a hazardous occupation; however, basic preventive measures can be taken to reduce the ESH hazards associated with this collection process.
GLOBAL WARMING, MAPPING, AND HAZARD RANKING, 1997 AIR EMISSIONS, IN 30 APPALACHIAN COUNTIES WITHIN WEST VIRGINIA, OHIO, AND PENNSYLVANIA. D. Whaley, G. Srinivasan, West Virginia University, Morgantown, WV
In 1997, air emissions of global warming gases and vapors, identified by the International Panel on Climate Change, were mapped using geographic information systems (GIS) for manufacturing sites in 30 counties in an Appalachian tri-state area near the Ohio and Kenawha Rivers, including parts of West Virginia, Ohio, and Pennsylvania. The sites mapped were air emission sources reporting annually to the U.S. EPA’s Toxic Release Inventory (TRI). The purpose of this work was to provide an objective method to rank hazard from global warming and present complex information simply as maps.
In 1997, eight facilities released to air these global warming vapors: chloroform, carbon tetrachloride, chlorodifluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethane, and dichloromethane. TRI reports only masses released to the environment.
We tabulated these six global warmers, with masses emitted to air, atmospheric lifetimes, and global warming potentials. Lifetimes in years range from 0.51 to 300. The global warming potential is a cumulative radiative forcing per unit mass of gas or vapor, relative to carbon dioxide as 1.0, from 1995 to the year 2015. Global warming potentials ranged from 0.14 to 7800.
A quantitative chemical hazard weighting factor — the Purdue Score, developed to measure progress in pollution prevention — has been enhanced to include global warming potential and atmospheric lifetime. We used the global warmer mass released/year times the Purdue hazard weighting factor — “hazpound product” — summed over all global warmers from a site to rank relative global warming hazard from air emissions, presented as maps.
Masses emitted range widely from 41 lbs/year to 357,000 lbs/year; corresponding hazpound values for hazard ranking also ranged widely, from 1562 to 7,205,100. Five of these eight facilities had emitted chlorodifluoromethane.
This objective, quantitative method can be used by industries and government to prioritize efforts to reduce hazard from global warming emissions.
RISK PERCEPTION OF THE RECYCLING OF DOMESTIC WASTEWATER: A FIVE-YEAR FOLLOW-UP. D. Nelson, M. Foster, OU-Civil Engineering and Environmental Science, Norman, OK
The purpose of this study was to follow up a 1994 survey of risk perceptions of community leaders and members of the Oklahoma Rural Water Association (ORWA) about wastewater recycling. Members attending the 1999 conference (conferees) or training classes (trainees) were asked to complete a five-page questionnaire about their local communities, opinions on wastewater recycling, and demographics. Results were tabulated and analyzed using SPSS.
Questionnaires were completed by 58 conferees and 127 trainees. The two groups were similar demographically; however, the conferees had a higher level of education and tended to work in management or administration. Conferees were less likely to respond “I would never consider recycling of wastewater” (13%) than were trainees (33%) (p=0.01). Trainees (9%) were less likely to see recycling as a viable conservation measure than were conferees (25%).
Education level was the strongest factor observed: 10% of high school attendees, 18% of college attendees, and 21% of college graduates believed recycling was a viable option. Of those who had never attended college, 39% would “never” consider reuse, as opposed to 17% (p=0.002) who had attended college.
As in the 1994 survey, the most frequent response (40%) was “need more information.” Women (56%) were more likely to be concerned about contamination of food; men (41%) were more likely to list “psychological repugnance.” Most acceptable uses were fire fighting and agricultural irrigation; least acceptable was drinking water. Similar to 1994, 29% of the 1999 conferees who did not expect future droughts would “never” consider wastewater reuse compared with only 3% of those who did expect shortages (p=0.007).
Community stakeholders in wastewater recycling decisions should thus be provided with accurate information about the potential of water shortages, sensitivity to concerns about psychological repugnance and food contamination, and multiple options for wastewater reuse.
USING THREE-DIMENSIONAL (3-D) SLIDES TO COMMUNICATE HAZARDS IN AGRICULTURE. D. Hubert, University of Texas Health Center, Tyler, TX
The ability to visually recognize agricultural hazards with the use of pretraining simulation exercises can lessen the injurious impact in actual hazardous environments. Safety professionals conducting regular training sessions in the mining industry have effectively used visual cues associated with common coal mine hazards to address the prevention of accidents.
Agricultural environments also contain many hazards that are not easily recognizable to individuals new to these environments. Similar to mining, individuals can be trained to recognize hazards without actually experiencing injury or near-injury events. With increasing numbers of families relocating to rural areas, the hazards associated with rural agricultural areas and activities might not be known by these newcomers.
Slide photographs taken with side-by-side mounted cameras provide three-dimensional (3-D) viewing of environments when viewed using a side-by-side slide viewer. In combination with narrative safety training materials, 3-D and 2-D graphics were used to enhance narrative simulation exercises for groups of secondary school agricultural teachers and students. These groups compared the effectiveness of incorporating 3-D vs. 2-D graphics in recognizing agricultural hazards highlighted in narrative exercises. Similar use of this technique in the coal mining industry demonstrated that 3-D slides were significantly more effective than the traditional 2-D graphics for depicting occupational hazards.
INTERACTIVE TRAINING METHODS ENHANCE INTRODUCTION OF WORKPLACE ERGONOMIC CONCEPTS. P. Grogin, Los Alamos National Laboratory, Los Alamos, NM
Employee awareness of the risk factors and controls for ergonomic injuries in the workplace is an essential element of an ergonomics program. Training is an effective method of increasing employee awareness, but if the attention of the employee is not held, retention of material is poor and the application of newly learned techniques often suffers. Lecture-style training alone has limited effectiveness in encouraging personnel to apply ergonomic solutions and focus on prevention of high-risk behaviors.
At Los Alamos National Laboratory (LANL), the Training Center employs dynamic techniques that support lecture material while stimulating employee interaction. Computer graphics, demonstrations, guided discussion, and hands-on exercises reinforce fundamental concepts and promote the application of knowledge during class.
Initially, lectures and videos are used to introduce risk factors and potential consequences of poor workplace ergonomics. Synthetic spines and hands detailing bones, nerves, ligaments, and tendons allow better visualization of those components of the body most susceptible to ergonomic injuries. Subsequently, computer graphics of LANL personnel demonstrating good and bad postures and work techniques are evaluated during an instructor-guided discussion that prompts the class to immediately apply the concepts introduced in lecture.
In one hands-on exercise, class members learn to adjust various ergonomically designed chairs, a task that personnel often admit they have yet to perform at their own workstations. In another exercise, the class surrounds a volunteer seated at a computer workstation. Responding to instructor questions and scenarios, the class suggests posture and workstation adjustments, which are demonstrated by the volunteer.
Conclusions: 1) The application of newly learned ergonomic concepts during class reinforces them for later use; 2) the use of familiar personnel demonstrating good and bad postures generates recognition, understanding, and acceptance; 3) initially apathetic employees demonstrate increased interest during and after participation in workstation adjustment activities.
MARINE OIL SPILL RESPONSE: HOW TO APPLY HAZWOPER TRAINING REQUIREMENTS. M. Garrahan, OSHA, Washington, DC; R. Laferriere, U.S. Coast Guard, Washington, DC; N. Baird, C. Duffield, ATL International, Inc., Germantown, MD
Since the early 1990s, OSHA has received inquiries from marine oil spill responders about how to apply HAZWOPER training requirements to their industry. To provide clear guidance in the language of the marine spill response industry, OSHA worked with the U.S. Coast Guard (USCG) to produce a training guide for marine responders. The new guide clearly outlines HAZWOPER emergency response training for different types of responders and different stages of spill response and cleanup.
The production of this new guide required substantial coordination between both federal agencies and offers an example of how combined expertise can result in better compliance guidance. Using sample tasks and exposures specific to marine oil spill response, the guide describes the different levels of training for emergency responders and post-emergency response cleanup workers. It provides a training flowchart and table of training requirements and training topics. It also offers an oil spill scenario that describes the HAZWOPER training required for the tasks described in the scenario.
The publication and distribution of this guide is expected to make HAZWOPER emergency response training requirements clear to this particular industry segment. Together with USCG, OSHA anticipates that improved training information can increase worker safety in marine oil spill response.
UTILIZATION OF SAFETY AND HEALTH FIELD ASSESSMENTS TO IMPROVE HAZARDOUS WASTE OPERATIONS AND EMERGENCY RESPONSE TRAINING. W. Brazile, Los Alamos National Laboratory, Los Alamos, NM
The Los Alamos National Laboratory (LANL) Environment Safety and Health Training group trains approximately 1000 Hazardous Waste Operations and Emergency Response (HAZWOPER) personnel annually. A large number of these personnel work at LANL Environmental Restoration (ER) and/or Decommissioning Decontamination (D/D) sites.
Formal health and safety oversight assessments are conducted at ER/D&D HAZWOPER sites by LANL oversight health and safety professionals. The assessments are conducted in compliance with the LANL Health and Safety Oversight Implementation Plan. Under this plan, HAZWOPER site deficiencies and noteworthy practices are documented based on a list of predetermined health and safety criteria from site-specific health and safety documents. The site deficiencies are addressed immediately and corrective actions are developed to prevent injuries, illnesses, or environmental impacts.
The deficiencies are made available to the Environment, Safety, and Health Training group for incorporation into the annual HAZWOPER refresher courses. LANL trainers develop and present these deficiencies in LANL training classes so HAZWOPER workers can prevent repeating the same or similar health and safety deficiencies in the field. By doing this, the annual HAZWOPER refresher courses are made relevant and meaningful to LANL personnel while still addressing the training requirements mandated by OSHA.
COLLECTION AND ANALYSES OF MYCOTOXINS FROM INDOOR ENVIRONMENTAL SUBSTRATES: POTENTIAL INTERFERENCES AND THE ROLE OF SPIKED SAMPLES. R. Salazar, Salazar & Spaul Environ. Consultants, Inc., Tampa, FL; Y. Hammad, P. Sherblom, University of South Florida, College of Public Health, Department of Environment and Occupational Health, Tampa, FL
Toxigenic fungi are often isolated from indoor environments. Production of mycotoxins by these organisms proliferating indoors is suspected. Mycotoxins, common contaminants of food and feed products, are known to cause serious illness and disease in humans and animals upon ingestion. Exposure to mycotoxins, if produced by organisms growing on indoor environmental substrates, may therefore present similar hazards to occupants in residential and occupational indoor settings.
To characterize suspected exposures to mycotoxins in indoor environments, development of specific and sensitive analytical methods is necessary. Methods published in the agricultural literature and specific to food and feed products are often applied to analyses of mycotoxins from indoor environmental substrates. Methods of mycotoxin extraction and detection specific to agricultural products, however, might not be appropriate for indoor environmental substrates.
In developing an analytical method for detection of mycotoxins from common indoor environmental substrates, this study evaluates analyses of the mycotoxins citrinin and ochratoxin A from ceiling tiles and carpet. Substrate samples spiked with known concentrations of toxin were subsequently analyzed using simple chemical methods. Extraction efficiencies are found to differ; toxin stability is found to influence recoverability.
This study evaluates methods of mycotoxin extraction and analyses from common indoor environmental substrates. The sensitivity and specificity of experimental methods are found to be substrate-specific. The role of spiked samples to determine toxin recoverability and method applicability to the particular substrate is illustrated.
OCCUPATIONAL EXPOSURE TO INDOOR ALLERGENS, PREVALENCE OF RESPIRATORY SYMPTOMS, AND ATOPY IN DOMESTIC-HELPERS. A. Pasanen, University of Kuopio, Kuopio, Finland; R. Merikoski, S. Pennanen, A. Harju, J. Liesivuori, Finnish Institute of Occupational Health, Kuopio, Finland
In this study, the prevalence of respiratory symptoms and skin prick reactions in domestic-helpers was evaluated. Allergen levels in selected work sites were also investigated. A questionnaire was distributed to 150 domestic-helpers; 118 (79%) responded. From those, 40 domestic-helpers were evaluated with skin prick tests. This group was matched regarding sex, age, and duration of working period. The skin prick allergens used were cat, dog, two house-dust mites, and three storage mites. In addition, dust samples (n = 57) were collected by vacuuming beds, carpets, or stuffed furniture in 57 dwellings, where 17 domestic-helpers visited during one working day. Levels of major cat (Fel d 1), dog (Can f 1), and house-dust mite (Der p 1) allergens in the dust samples were analyzed by two-site enzyme-linked immunosorbent assay methods.
The prevalence of eye, nasal, and throat symptoms and cough in responding domestic-helpers was 19%, 28%, 15%, and 10%, respectively. Similar results were found in the group characterized by skin prick tests. A significantly higher prevalence (up to 47%) was detected in workers whose working environments were studied.
Of the subjects, 2.5%-5% had a positive result to cat, dog, or house-dust mites, with 7.5%-20% reacting to storage mites. Cat and dog allergens were determined in 96%-98% of the dwellings; Der p 1 was found in 21%. The concentrations of Fel d 1, Can f 1, and Der p 1 were 0.08-245, 0.48-106, and 0.0008-0.015 µg/g, respectively. The sensitization threshold for cat allergen (1 µg/g) was exceeded in 26% of the work sites. The dog allergen threshold (2 µg/g) was exceeded in 30% of the sites studied. Results indicate that the prevalence of respiratory symptoms and atopy was not particularly high in the domestic-helpers who responded. However, they may be exposed to allergen levels sufficient to result in sensitization.
INTERPRETATION OF INDOOR CARBON DIOXIDE. S. Rhodes, ETIH, Walkersville, MD; T. Horan, Social Security Administration, Towson, MD; T. Kallio, Certified Industrial Hygienist, Columbia, MD
The measurement of carbon dioxide (CO2) is perhaps the most widely used tool in indoor environmental quality investigations. ASHRAE has indicated that “comfort (odor) criteria is likely to be satisfied if the ventilation rate is set so that 1000 ppm CO2 is not exceeded” (ASHRAE 62-1989, Ventilation for Acceptable Indoor Air Quality).
The guideline suggests to many a benchmark of acceptability. Without a thorough understanding of indoor CO2, as well as the assumptions and rationale used to derive the 1000 ppm guideline, inappropriate sampling strategies are employed and the data misinterpreted. Spurious data or the misinterpretation of data can incur costs from increased energy outlays, unnecessary equipment modifications, and occupant anxiety. Conversely, erroneous conclusions may falsely suggest adequate ventilation. The ventilation rates recommended by ASHRAE 62-1989 reflect the general agreement that these outdoor ventilation rates would control CO2, particulates, odors, and other contaminants at acceptable concentrations.
The 1000 ppm guideline is based on a mass balance equation that quantifies the amount of outdoor air needed to maintain a constant concentration of CO2 below a specified level. In short:
Ventilation Rate = CO2 Generation Rate/((Max. Indoor CO2 Conc. - Outdoor CO2 Conc.) (Time))
Data that are not representative of real conditions may result if 1) sampling is conducted when the space is not at full occupancy; 2) samples are collected near sources, or near the return or supply; 3) the system is not operating nominally; or 4) sampling is conducted before or after the peak CO2 concentration.
The common misinterpretations of data involve 1) suggestion of a toxicological/physiological response to CO2; 2) determination of reasonable ventilation without information about occupant density; 3) extrapolating results from a single datum or insufficient/inappropriate data; or 4) estimating the adequacy of ventilation rate from data in which the CO2 concentration has not reached equilibrium.
A thorough understanding of the standard, CO2, and appropriate sampling methods is imperative for the effective use of this indicator of indoor ventilation.
UTILITY OF TWO MOISTURE METER TYPES IN ASSESSING LATENT INTERIOR MOISTURE. T. Ryan, Ohio University, Athens, OH
Invasive (pinned) and noninvasive relative moisture meters are increasingly used in indoor environmental quality investigations where water and concomitant microbial growth is a concern. This project examined the ability of two such devices in assessing room moisture in office buildings.
Typically dry and characteristically wet locations in 30 facilities were studied. Both location pairs were evaluated during periods of dry building exterior, and following heavy rainfalls. Moisture content in basement or grade-level concrete floors was assessed with a Tramex Concrete Encounter® meter capable of noninvasively measuring between 2%-6% moisture. Wall, ceiling, or carpet moisture content was determined with a Delmhorst moisture meter capable of measuring between 6%-40% moisture when using invasive 1- to 4-inch pins. Simultaneously, room and floor relative humidity and temperature were recorded for all areas. Soils adjacent to study facilities’ exterior walls were also measured with the 4-inch pinned meter.
Results showed no significant meter reading increases between wet or dry locations, even when room air relative humidity was shown to increase by almost 10% owing to external rainfall. Furthermore, there was no correlation between the two meter types (Tramex or Delmhorst) in wet or dry locations. Use of the 4-inch pins for soil moisture measurements were frequently off-scale.
Absent any obvious indications of water intrusion in a facility, both meters were insensitive to moderate room moisture increases. Their effective use may be confined to fairly obvious water intrusion events, or to the study of Exterior Finish and Insulation Systems (EIFS) where through-the-wall moisture problems are the primary concern. Despite these limitations, readings obtained in this study might be of use as a baseline database for comparison in severe water intrusion instances.
A COMPARISON OF PM10 AND PM2.5 CONSTITUENTS IN INDOOR AND OUTDOOR ENVIRONMENTS. D. Westbrook, MSPH, Environmental Strategies Corporation, Reston, VA; D. Lillquist, Ph.D., CIH, T. Aldrich, Ph.D., L. Lyon, MD, MPH, University of Utah, Salt Lake City, UT
Associations between particulate matter and health have been calculated based on ambient air quality data collected from centrally located monitoring stations. Human activity studies, however, have shown that people spend greater than 80% of their time in indoor environments. The importance of indoor environments must be considered when estimating exposures to particulate matter. The chemical composition of ambient and indoor particulate matter also needs to be investigated when assessing how personal exposure, particle size, and elemental composition plausibility influences toxicity.
The purpose of this research is to compare indoor and outdoor PM10 and PM2.5 concentrations in terms of both mass and elemental composition. The comparison will help establish 1) the relationship between outdoor and indoor particulate concentrations for both PM10 and PM2.5; 2) the chemical species present in indoor and outdoor particulate matter at both PM10 and PM2.5 size ranges; and 3) estimates of the contribution of outdoor pollution to indoor air pollution.
Samples were collected at three extended nursing facilities in Salt Lake County in the winter of 1998 during the atmospheric inversion season when PM levels were anticipated to be elevated. Overall, the indoor PM10 and PM2.5 levels were higher than the corresponding outdoor levels.
The indoor-to-outdoor ratios for particulate matter were different between nursing homes. These differences can be explained by indoor sources and individual building characteristics. The indoor PM10 and PM2.5 concentrations did not correlate well with their corresponding outdoor levels. Several regression equations had negative slope coefficients which are not intuitive relationships. However, the elemental analysis suggested particle infiltration rates to be approximately 50% and 75% for PM10 and PM2.5, respectively. The paired PM10 and PM2.5 concentrations between indoor and outdoor environments were highly correlated, suggesting that PM10 is a good predictor of PM2.5 mass.
COMPARISON STUDY BETWEEN SF6 TRACER GAS ANALYSIS AND AMBIENT AIR CONTAMINANT MONITORING TO QUANTIFY AIR ENTRAINMENT IN A STORAGE FACILITY. N. Wegener, D. Lillquist, RMCOEH, University of Utah, Salt Lake City, UT; M. Taylor, Risk Management, LDS Church, Salt Lake City, UT
Ambient air contaminant monitoring methods for ozone and nitrogen oxides (NOx) were compared to sulfur hexafluoride (SF6) tracer gas analysis. The comparison was to determine which method best characterized air contaminant entrainment into a microfilm storage facility.
The NOx was measured using integrated sampling techniques, and ozone measurements were conducted using a real-time monitor. Both ambient indoor and outdoor levels of the two air pollutants were gathered. Low levels of ozone made it difficult to gain useful data to characterize outdoor air contaminant entrainment. The results of the NOx monitoring showed indoor levels to be between 40% and 60% of the outdoor levels. SF6 tracer gas analysis was accomplished using a real-time multiport monitor capable of measuring several different remote locations. By releasing a small quantity of SF6 into the production area of the facility, a simulation of the entrainment of an air pollutant or industrial air contaminant was modeled.
The results of the tracer gas analysis effectively illustrated the locations throughout the facility that had the highest percentages of SF6 when compared with the production area of the facility. The highest percentage was 12%, the lowest 6.3%. The locations where these concentrations occurred help characterize where the greatest concentration of air contaminant may accumulate.
These findings from both the air contaminant monitoring and the tracer gas analysis allow the conclusion that by conducting a preliminary tracer gas analysis of a facility, an entrainment model can be established. Thereafter, the model can be used in order to most effectively locate and sample for specific air contaminants.
THE CONTINUING ADVENTURES OF NIOSH INVESTIGATORS DURING AN IEQ INVESTIGATION. G. Burr, K. Martinez, R. Malkin, NIOSH, Cincinnati, OH
In 1998, NIOSH conducted an indoor air quality (IEQ) evaluation at a large midwestern high school (3000+ students, 350 teachers) constructed in the 1970s. Staff and students were experiencing problems related to poor IEQ in the school, including sinus cancer, memory problems, inability to concentrate, metallic taste, bleeding lungs, dizziness, depression, respiratory problems, lethargy, chronic fatigue, chest congestion, burning eyes and throat, and nausea.
This survey included employee interviews and evaluation of the heating, ventilation, and air-conditioning (HVAC) systems, and a visual examination for fungal growth in the building. Measurements were made for carbon dioxide (CO2), temperature, and relative humidity (RH), and bulk samples were collected for subsequent analysis of bacterial and fungal content. The CO2 concentrations increased during the school day (peaking at 1500 ppm) while the temperature and RH ranged from 68°F to 75°F and 17% to 23%, respectively. Localized microbial reservoirs in the school existed at the time of the NIOSH site visit, and ongoing moisture incursion or moist conditions were noted.
The presence of Stachybotrys fungal species in some locations was probably indicative of a small residual from past contamination. The presence of Cladosporium fungal species in the interior duct insulation of several HVAC units suggested that the previous duct cleaning performed at the school might have been ineffective. In addition to the environmental sampling results, this poster discusses the employee interviews and examines other events that impacted on the conduct of this evaluation, including involvement by community action groups and the local media (newspapers and television stations).
This poster also describes recommendations made for a further evaluation of the ventilation systems, identification and correction of water incursion problems, remediation of identified localized patches of mold, and the hiring of an environmental quality manager at the school.
EMISSION SOURCE IDENTIFICATION OF INDOOR AIRBORNE FIBER. J. Chen, Duke University Medical Center, Durham, NC
Man-made vitreous fiber (MMVF) released from ventilation duct insulation was found to be a potential source of indoor pollutant. This study provides a quantitative method to differentiate airborne fiber emission sources from HVAC systems and room environments. Airborne fiber concentrations were measured in offices and laboratories in four buildings from 22 to 31 years old with internal MMVF ventilation duct insulation. The concentrations were determined according to NIOSH 7400 with sampling air volume greater than 2000 L for most samples.
One diffuser and one area sample were collected at each location. The diffuser sample was collected inside a bag that was attached to the diffuser and, thus, isolated the supply air through the HVAC system from the room environment. A concurrent area sample was taken in the same room for comparison. An outdoor sample was also taken for each sampling date.
Twenty-nine paired diffuser and area samples and 11 outdoor samples were taken and analyzed between August 1998 and August 1999. Concentrations of diffuser samples ranged from 0.00000 fibers per cubic centimeter (f/cc) to 0.00143 f/cc, area samples ranged from 0.00015 f/cc to 0.00955 f/cc, and outdoor samples ranged from 0.00029 f/cc to 0.00126 f/cc.
It was concluded that the indoor airborne fiber concentrations were low and most of the fibers observed were not MMVFs. This indicated that little MMVF was released from the duct insulation. Concentrations of area samples were significantly higher than diffuser samples using two-tailed, paired t-test (CI = 95%, p = 0.007). This implied that sources, including human, other than from the HVAC system would significantly increase the indoor airborne fiber concentration. Research relating to fiber release from the HVAC system should conduct diffuser samples instead of area samples to avoid bias.
PROACTIVE BUILDING INDOOR AIR QUALITY INVESTIGATIONS. J. Koehn, S. Coleman, JK, Inc., Houston, TX
Building owners and/or management company personnel have become increasingly aware of the effect of current indoor air quality (IAQ) status on building occupants. Various responses have ranged from reactive to proactive measures with respect to reports of sick building syndrome (SBS) as well as complaints of odors or poor indoor air quality.
Our consulting group has seen implementation of a more proactive approach to assessment of IAQ status for a wide range of facilities, including school districts, leased tenant spaces, and general management of occupied high rise buildings. Some clients have contracted for conduct of quarterly monitoring of basic IAQ parameters as well as microbial agents. Other clients have specified monitoring for standard chemical parameters, particulates, total volatile organic compounds (TVOCs), and airborne bioaerosols associated with building renovation work activities in order to provide baseline documentation.
The goal of most monitoring projects is to document existing environmental conditions related to current facility indoor air quality. Initial walk-through surveys of buildings by industrial hygienists have yielded information for development of an appropriate air sampling strategy to best measure concentrations of “potentially hazardous” substances that could reasonably be expected to exist within the workplace environments.
Scheduled monitoring efforts have been performed based on specific needs such as quarterly or annual time intervals in order to document conduct of a representative IAQ based on accepted work practices and procedures or to complete workplace surveillance to identify potential harmful occupational exposures.
A flexible approach to implementation can be designed to obtain the appropriate monitoring data to best describe and document current IAQ status. Based on the results obtained, appropriate control measures can be developed.
RESPIRATORY PROTECTION REQUIRED DURING AUTOBODY PAINT SPRAYING. L. May, OSHA, Bridgeport, CT
There is national, state, and local interest in respiratory illnesses associated with spray finishing operations, particularly those using isocyanates. According to NIOSH, approximately 30% percent of adult asthma cases may be attributed to occupational exposure.
Of the known work-related asthmagens, isocyanates are referenced as the most common cause of occupational asthma. Problems tend to range from respiratory irritation to occupational asthma. Cases of isocyanate-induced asthma in autobody workers have been documented to be between 5% and 10% in Connecticut.
Having recognized the potential respiratory hazards found within autobody operations, we inspected 25 autobody establishments within our jurisdiction. Of these 25, deficiencies were found at 19 establishments. The total number of employees exposed to potential hazardous conditions was 101. The most frequently found problem during our inspections was deficiency in the employer’s respiratory protection program. Of the 101 potentially exposed employees, 86% or 85% had not been medically cleared to wear respirators.
In 10 establishments, the proper respirators were not being used, specifically when there was potential for an IDHL atmosphere, for spraying products containing isocyanates. In these 10 inspections, 54 employees (or 53% of the total population) were potentially exposed.
Most employers were not aware of the fact that isocyanates are primary sensitizers and that if an employee became sensitized, he or she would no longer be able to work in a job that would expose him or her to these materials. The inspections revealed that in nine establishments 49 employees (or 49% of the total population) had not received any training in hazard communication, which included training of the potential hazards of isocyanate exposure.
RESPIRATOR SUBJECTIVE ASSESSMENT IN AUTOBODY REPAIR SHOPS. Y. Liu, J. Sparer, M. Cullen, M. Stowe, C. Holm, C. Redlich, Yale University School of Medicine, New Haven, CT; S. Woskie, D. Bello, University of Massachusetts-Lowell, Lowell, MA
Subjective evaluation of respiratory protection devices (RPDs) used in autobody shops has been rarely reported. The purpose of this study was to evaluate subjective estimates of comfort and efficiency of negative- and positive-pressure respirators in real autobody work conditions. As part of a large epidemiologic study, 47 workers from 12 autobody shops participated in this evaluation. Subjective assessments included comfort, visual and respiratory discomfort, ease to put on and maintain in place, protection efficiency, and a summary evaluation of respirator use.
Worker judgment of an acceptable wearing duration was also evaluated. Assessment parameters were contained in a booklet with each on a separate page. Each parameter was presented on a 5- or 6-point vertical scale. Subjects were asked to mark a place on the scale. The distance (in millimeters) between the lower end of the scale and the point marked by the subject was measured and averaged for each parameter and compared among types of RPDs and workers.
Results showed that supplied-air respirators had the highest ratings with good comfort, minimal breathing and visual discomfort, ease to put on and maintain, and perceived good protection. Half-masks with organic cartridges and paint filters were considered by the workers as even easier to put on and maintain, but they were perceived as providing less protection efficiency and comfort. They were also reported as causing slight visual and breathing discomfort.
N95 dust masks were perceived as easy to put on and maintain, but workers regarded their protection as less efficient than the other respirators. Workers judged the acceptable duration of wear for cartridge respirators and dust masks as 107 and 152 minutes, respectively.
These results may be considered in setting up a respiratory protection program for autobody shop workers.
EXPOSURE PROFILE EFFECTS ON QUANTITATIVE FIT-FACTOR ASSESSMENT. D. Dalamagas, Harder Mechanical Contractors, Portland, OR; C. Coffey, Z. Zhuang, NIOSH, Morgantown, WV
The purpose of this study was to correlate quantitative fit-factors to specific exposures by measuring Freonā-113 in a wearer’s exhaled breath. This was done by determining whether identical exposures, occurring at different times during a 30-minute simulated workplace test (SWPT), would result in different end-exhaled air concentrations (EACs) of Freonā-113.
The study consisted of three phases, each with four different subjects. End-exhaled air samples were collected 30 minutes after the SWPT and analyzed by gas chromatography. The first phase consisted of four exposure scenarios: 1) 500 ppm during the first minute of the SWPT; 2) 500 ppm during the last minute of the SWPT; 3) 33 ppm during the first 15 minutes of the SWPT; and 4) 33 ppm during the last 15 minutes of the SWPT.
The second phase consisted of 1) 500 ppm during the first six minutes of the SWPT; and 2) 500 ppm during the last six minutes of the SWPT. The third phase consisted of 1) 500 ppm during the first two minutes, between 15 and 16 minutes, and between 28 and 30 minutes of the SWPT; and 2) continuous exposure of 100 ppm during the entire SWPT.
No significant difference was found between the means for these scenarios except that the means of scenario 2 of phase 1 was higher for two subjects. A significance level of 0.05 was used for all analyses.
It was concluded that exposures of the same magnitude produced the same EACs regardless of when they occurred. Freonā-113 EAC can be used to determine the actual level of protection provided by an air-purifying respirator.
COMPARISON OF SIX RESPIRATOR FIT-TEST METHODS WITH AN ACTUAL MEASUREMENT OF EXPOSURE USING FULL-FACEPIECE RESPIRATORS. C. Coffey, Z. Zhuang, R. Lawrence, P. Jensen, NIOSH, Morgantown, WV
A recent study found that some quantitative fit-test (QNFT) methods may be predictive of actual half-mask respirator performance. The purpose of this study was to determine whether the same degree of predictability could be found using full-facepiece respirators.
Fit-factors from six QNFT methods performed under laboratory conditions were compared with the exposure to 1,1,2 trichloro-1,2,2 trifluoroethane (Freonā-113) assessed by exhaled breath analysis. The six QNFT methods were 1) low flow, flush probe corn oil (CLF); 2) high flow, deep probe corn oil (CHD); 3) controlled negative pressure (CNP); 4) ambient aerosol, 10 minutes, six exercises (AA1); 5) ambient aerosol, 30 minutes, 17 exercises (AA2); and 6) high flow, deep probe ambient aerosol (AAHD).
Each method was conducted on a sample of 30 subjects with three replications. Each subject randomly selected 3 of 10 organic vapor/P100 full-facepiece respirators. The exhaled breath of each subject exposed to 500 ppm of Freonā-113 was first evaluated at 30 minutes post-exposure. This characterization was then used to estimate the actual exposure to Freonā-113 during correlation testing. Fit-factors resulting from the QNFT protocols were then individually correlated with the Freonā-113 exposures using the coefficient of determination, R2.
Statistically significant correlation between fit-factors and actual exposure doses of Freonā-113 was found with some QNFT methods. But the highest R2 value was only 0.20. The correlations were not as strong as those observed with the half-mask respirators in the previous study.
The results of this study suggest that some QNFT methods can predict actual performance of full-facepiece respirators.
SUGGESTING THE DIRECTION FOR DEVELOPMENT OF SOME RESPIRATOR FILTERS IN KOREA. D. Han, Inje University, Kimhae, Republic of Korea
Most manufacturers try to produce the most efficient filter for respirators with the lowest breathing resistance. Filter performance depends on the low aerosol penetration (i.e., high efficiency [%] and pressure drop [mmH2O]). Performance of mechanical respirator filters depends considerably on the proportion of mixing of raw materials, such as glass fiber, mini fiber, activated carbon fiber, and pulp, which is very important to produce a good quality filter.
This study was performed to suggest the direction for development of some mechanical filters and filtering facepieces that performed well in Korea. Two mechanical filters, S and K (made in Korea) and three filtering facepieces (S made in China, C in Korea, and M in the United States) - all of which are widely used in Korean workplaces - were chosen to be tested for aerosol penetration and pressure drop.
Twenty filters of each were tested with TSI Incorporated’s Automated Filter Tester Model 8110ā using polydisperse NaCl for types of test particles. Aerosol penetration and pressure drop were measured for four constant airflow rates at 10, 32, 64, and 85 L/min. Mechanical filter S showed that aerosol penetration rates were very low at all airflow rates compared with Korean standards (<5% at airflow rate 30 L/min), but pressure drops increased dramatically at airflow rates of more than 32 L/min, even though its pressure drop was in compliance with Korean standards 6 mmH2O at the 30 L/min airflow rate.
Mechanical filter K showed that penetration rates and pressure drops were higher than those of S, and increased linearly with airflow rates. The results indicated that mechanical filter S should decrease pressure drop without increasing efficiency, but K should decrease pressure drop and increase efficiency simultaneously for better quality. While filtering facepiece M performed well compared with Korea standards, S and C were improved for both efficiency and pressure drop.
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