Efficacy of occupant-collected dust samples in the evaluation of residential allergen and fungal levels.

This study evaluated the ability of a resident to evaluate their home for allergens and mold using a settled dust test kit compared with evaluation and collection of settled dust by an industrial hygienist. Forty-three home residents were provided with a kit containing written instructions and a vacuum cleaner attachment for collecting a settled dust sample. Within 2 weeks of receiving the occupant-collected sample, an industrial hygienist evaluated these homes, including a visual inspection, collection of settled dust, and collection of spore trap samples. Settled dust samples were analyzed for major dog, cat, dust mite, and cockroach allergens using immunoassay methods, and for mold spore equivalents using quantitative polymerase chain reaction methods for the 13 mold species or species groups comprising the American Relative Moldiness Index (ARMI). Allergen concentrations and ARMIs were compared between the resident- and industrial hygienist-collected samples. Linear regression between the two sets of samples showed strong correlations for dog allergen (r(2) = 0.92) and cat allergen (r(2) = 0.90). Correlations for dust mite (r(2) = 0.57) and cockroach allergens (r(2) = 0.22) were lower, likely due to most samples being near the limit of detection. ARMIs were highly correlated (r(2) = 0.68) and were in categorical (high, medium, or low) agreement for 76% of residences. These results show that residents can reliably follow directions and collect settled dust samples, providing an efficient method to remotely screen homes for elevated allergen levels and to identify homes with a potential mold or moisture problem that may need further evaluation.

Diacetyl exposures in the flavor manufacturing industry.

Recently, worker exposures to diacetyl, a chemical used in the production of butter popcorn, has been linked to bronchiolitis obliterans, a severe lung disease. This chemical is also used in the flavor industry to confer a buttery flavor to many food products, with more than 228,000 pounds used in 2005. Diacetyl exposures were monitored at 16 small-to medium-sized flavor facilities to determine potential diacetyl exposures. A total of 181 diacetyl samples (both personal and area samples) were obtained, and a number of real-time samples were collected using an IR spectrometer. Samples were obtained during liquid and powder compounding operations at the facilities as well as during laboratory and QC operations. The personal and area samples ranged from non-detectable (<0.02 ppm) to as high as 60 ppm. Ninety-two (51%) of the samples were below the limit of detection, and the mean diacetyl concentration for all processes was 1.80 ppm. Mean diacetyl levels during powder operations were generally higher (4.24 ppm) than mean diacetyl levels during liquid operations (2.02 ppm). Maximum real-time diacetyl exposures during powder operations could reach as high as 525 ppm. These results are similar to exposures measured by NIOSH in popcorn facilities where lung disease was found; however, the duration of use and frequency of use may be significantly lower.

Perceptions of indoor air quality associated with ventilation system types in elementary schools.

With the increased utilization of school buildings on a year-round basis, school indoor air quality has become a national concern. The purpose of this study was to evaluate possible associations between ventilation system type and occupant perception of indoor air quality. Staff (n = 403) from 12 schools completed a self-administered questionnaire. Carbon dioxide (CO2) levels, air exchange rates, and particle counts were also measured for each school. Schools with unit ventilator (UV) systems had the lowest mean CO2 level at 637 ppm, followed by the variable air volume (VAV) systems with 664 ppm, and constant volume (CV) systems with a mean of 703 ppm. Schools with UV systems had the lowest mean air exchange rate at 2.67 air changes per hour (ACH), followed by the VAV system type at 2.80 ACH and the CV system type at 4.61 ACH. Indoor versus outdoor particle ratios were calculated for each ventilation system type. Particles with aerodynamic diameters ranging from 0.1-1.0 microm had a geometric mean ratio ranging from 0.38 to 0.68; particles with aerodynamic diameters ranging from 1-3 microm had ratios ranging from 1.39 to 5.47, and particles with aerodynamic diameters greater than 3 microm had ratios ranging from 3.20 to 14.76. Schools using VAV systems had a significantly lower prevalence of red and watery eyes while schools with UV systems had an elevated prevalence of nasal congestion, sore throat, headache, and dustiness complaints. This increased prevalence of complaints in buildings with UV systems may be due to the increased particulate levels.

Beryllium particulate exposure and disease relations in a beryllium machining plant.

We examined the relationship between exposure to beryllium and the presence of beryllium sensitization (BeS) and chronic beryllium disease (CBD) in a cohort of workers in a beryllium precision machining facility. Twenty workers with BeS or CBD (cases) were compared with 206 worker-controls in a case-control study. Exposure for each job title was measured using cascade impactors placed in the workers' breathing zone to measure total beryllium exposure and exposure to particles < 6 microns and < 1 micron in aerodynamic diameter. Cumulative exposure was calculated as sigma (job title exposure estimate x years in job title). Individual lifetime-weighted (LTW) exposure was calculated as sigma [(job title exposure x years in job title) divided by total years employment)]. Workers in the case group were more likely to have worked as machinists (odds ratio, 4.4; 95% confidence interval, 1.1 to 17.5) than those in the control group. The median cumulative exposure was consistently greater in the cases compared with the controls for all exposure estimates and particle size fractions, although this was not statistically significant. The median cumulative exposure was 2.9 micrograms/m3-years in the cases versus 1.2 micrograms/m3-years in the controls for total exposure, and 1.7 micrograms/m3-years in the cases versus 0.5 microgram/m3-years in the controls for exposure to particles < 6 microns in diameter. With cumulative exposure categorized into low-, intermediate-, and high-exposure groups, the odds ratios were 2.4 (95% confidence interval, 0.7 to 8.2) for the intermediate-exposure group and 1.2 (95% confidence interval, 0.4 to 4.2) for the high-exposure group compared with the low-exposure group. The median LTW exposure was 0.25 microgram/m3 in both groups. The median LTW exposure to particles < 6 microns was 0.20 microgram/m3 in the cases compared with 0.14 microgram/m3 in the controls. The differences in cumulative and LTW exposure were not statistically significant. None of the 22 workers with LTW exposure < 0.02 microgram/m3 had BeS or CBD. Twelve workers (60%) in the case group had LTW exposures > 0.20. In conclusion, increased cumulative and LTW exposure to total and respirable beryllium was observed in workers with CBD or BeS compared with the controls. These results support efforts to control beryllium exposure in the workplace.

Development of an exposure database and surveillance system for use by practicing OSH professionals.

This report summarizes the development of an occupational exposure database and surveillance system for use by health and safety professionals at Rocky Flats Environmental Technology Site (RFETS), a former nuclear weapons production facility. The site itself is currently in the cleanup stage with work expected to continue into 2006. The system was developed with the intent of helping health and safety personnel not only to manage and analyze exposure monitoring data, but also to identify exposure determinants during the highly variable cleanup work. Utilizing a series of focused meetings with health and safety personnel from two of the major contractors at RFETS, core data elements were established. These data elements were selected based on their utility for analysis and identification of exposure determinants. A task-based coding scheme was employed to better define the highly variable work. The coding scheme consisted of a two-tiered hierarchical list with a total of 34 possible combinations of work type and task. The data elements were incorporated into a Microsoft Access database with built-in data entry features to both promote consistency and limit entry choices to enable stratified analyses. In designing the system, emphasis was placed on the ability of end users to perform complex analyses and multiparameter queries to identify trends in their exposure data. A very flexible and user-friendly report generator was built into the system. This report generator allowed users to perform multiparameter queries using an intuitive system with very little training. In addition, a number of automated graphical analyses were built into the system, including exposure levels by any combination of building, date, employee, job classification, type of contaminant, work type or task, exposure levels over time, exposure levels relative to the permissible exposure limit (PELS), and distributions of exposure levels. Both of these interfaces, allow the user to "drill down" or gradually narrow query criteria to identify specific exposure determinants. A number of other industrial hygiene processes were automated by the use of this database. Exposure calculations were coded into the system to allow automatic calculation of time-weighted averages and sample volumes. In addition, a table containing all the PELs and other relevant occupational exposure limits was built into the system to allow automatic comparisons with the current standards. Finally, the process of generating reports for employee notification was automated. The implementation of this system demonstrates that an integrated database system can save time for a practicing hygienist as well as provide useful and more importantly, timely information to guide primary prevention efforts.

Integrating workplace exposure databases for occupational medicine services and epidemiologic studies at a former nuclear weapons facility.

We outline methods for integrating epidemiologic and industrial hygiene data systems for the purpose of exposure estimation, exposure surveillance, worker notification, and occupational medicine practice. We present examples of these methods from our work at the Rocky Flats Plant--a former nuclear weapons facility that fabricated plutonium triggers for nuclear weapons and is now being decontaminated and decommissioned. The weapons production processes exposed workers to plutonium, gamma photons, neutrons, beryllium, asbestos, and several hazardous chemical agents, including chlorinated hydrocarbons and heavy metals. We developed a job exposure matrix (JEM) for estimating exposures to 10 chemical agents in 20 buildings for 120 different job categories over a production history spanning 34 years. With the JEM, we estimated lifetime chemical exposures for about 12,000 of the 16,000 former production workers. We show how the JEM database is used to estimate cumulative exposures over different time periods for epidemiological studies and to provide notification and determine eligibility for a medical screening program developed for former workers. We designed an industrial hygiene data system for maintaining exposure data for current cleanup workers. We describe how this system can be used for exposure surveillance and linked with the JEM and databases on radiation doses to develop lifetime exposure histories and to determine appropriate medical monitoring tests for current cleanup workers. We also present time-line-based graphical methods for reviewing and correcting exposure estimates and reporting them to individual workers.

Cleanup worker exposures to hazardous chemicals at a former nuclear weapons plant: piloting of an exposure surveillance system.

Cleanup of former U.S. Department of Energy (DOE) nuclear weapons production facilities involves potential exposures to various hazardous chemicals. We have collaboratively developed and piloted an exposure database and surveillance system for cleanup worker hazardous chemical exposure data with a cleanup contractor at the Rocky Flats Environmental Technology Site (RFETS). A unique system feature is the incorporation of a 34-category work task-coding scheme. This report presents an overview of the data captured by this system during development and piloting from March 1995 through August 1998. All air samples collected were entered into the system. Of the 859 breathing zone samples collected, 103 unique employees and 39 unique compounds were represented. Breathing zone exposure levels were usually low (86% of breathing zone samples were below analytical limits of detection). The use of respirators and other exposure controls was high (87 and 88%, respectively). Occasional high-level excursions did occur. Detailed quantitative summaries are provided for the six most monitored compounds: asbestos, beryllium, carbon tetrachloride, chromium, lead, and methylene chloride. Task and job title data were successfully collected for most samples, and showed specific cleanup activities by pipe fitters to be the most commonly represented in the database. Importantly, these results demonstrate the feasibility of the implementation of integrated exposure database and surveillance systems by practicing industrial hygienists employed in industry as well as the preventive potential and research uses of such systems. This exposure database and surveillance system--the central features of which are applicable in any industrial work setting--has enabled one of the first systematic quantitative characterizations of DOE cleanup worker exposures to hazardous chemicals.

Aerosols generated during beryllium machining.

Some beryllium processes, especially machining, are associated with an increased risk of beryllium sensitization and disease. Little is known about exposure characteristics contributing to risk, such as particle size. This study examined the characteristics of beryllium machining exposures under actual working conditions. Stationary samples, using eight-stage Lovelace Multijet Cascade Impactors, were taken at the process point of operation and at the closest point that the worker would routinely approach. Paired samples were collected at the operator's breathing zone by using a Marple Personal Cascade Impactor and a 35-mm closed-faced cassette. More than 50% of the beryllium machining particles in the breathing zone were less than 10 microns in aerodynamic diameter. This small particle size may result in beryllium deposition into the deepest portion of the lung and may explain elevated rates of sensitization among beryllium machinists.

"Lifeguard lung": endemic granulomatous pneumonitis in an indoor swimming pool.

OBJECTIVES: Two sequential outbreaks of respiratory disease among lifeguards at an indoor swimming pool with water spray features were investigated. METHODS: Questionnaires were administered to recreation center employees following each outbreak. Respondents reporting 2 or more pool-related symptoms were offered clinical evaluation, including bronchoscopy with bronchoalveolar lavage and transbronchial biopsy. Pool air and water were sampled for fungi, bacteria, amoebae, endotoxin, and respirable particulates. RESULTS: Thirty-three lifeguards had noncaseating granulomas on biopsy and/or bronchoalveolar lavage lymphocytosis. Attack rates for the outbreaks were 27% and 65%. Case patients had higher cumulative hours of work and tended to work more hours per week. Analyses indicated increased levels of endotoxin in pool air and water (relative to control pools) and gram-negative bacterial colonization of water sprays. Use of water spray features generated a 5.2-fold increase in the number of respirable particles and up to an 8-fold increase in air endotoxin levels. CONCLUSIONS: Lifeguards in this indoor swimming pool developed granulomatous lung disease associated with endotoxin-containing respirable bioaerosols from water spray features, which ventilation system improvements did not prevent.

Endemic work-related febrile respiratory illness among construction workers.

Construction workers building Denver International Airport (DIA) reported work-related respiratory and flulike symptoms of several months duration. We performed a cross-sectional interview study of 495 randomly selected DIA workers from six contractors in comparison with preplacement workers. We defined cases as workers with two work-attributed lower respiratory symptoms and one work-attributed systemic symptom. Case rates were significantly higher among DIA workers (34%) compared with those who had never worked at DIA (2%). Risk factors for illness included exposure to fireproofing (OR, 4.21; 95% CI, 1.95-9.08), work in tunnels and adjoining areas (OR, 3.07; 95% CI, 1.84-5.12), length of DIA employment (OR, 0.65; 95% CI, 0.46-0.92), and preexisting bronchitis (OR, 2.43; 95% CI, 1.17-5.05). Our industrial hygiene investigation revealed alkaline dust (pH 11) present at a worksite associated with elevated risk of illness, and we identified airborne Penicillium mold widely distributed indoors at DIA. Clinical evaluation of 26 self-identified symptomatic DIA employees, including bronchoalveolar lavage and biopsy in 10, revealed work-related asthma in three workers and histologic evidence of chronic bronchitis in four who had never smoked. We concluded that future investigations of endemic work-related febrile respiratory illness among construction workers should evaluate its association with indoor exposure to dusts from alkaline fireproofing, Penicillium mold, mycotoxins, and bacterial bioaerosols.

Epidemiology of beryllium sensitization and disease in nuclear workers.

We examined the epidemiology of chronic beryllium disease among a stratified, random sample (n = 895) of nuclear weapons workers using the blood beryllium lymphocyte transformation (BeLT) test and chest radiograph for case identification. Of 18 new cases of beryllium sensitization, 12 had beryllium disease, and three more developed pulmonary granulomas on lung biopsy over the succeeding 2 yr. Beryllium-sensitized cases did not differ from noncases in age, gender, race, ethnicity, smoking, most respiratory symptoms, spirometric or radiographic abnormalities, or job tenure. The six sensitized cases without initial disease differed from beryllium disease cases in having greater pack-years of smoking. Sensitization occurred among workers with inadvertent or bystander exposure, such as a secretary and security guard. However, beryllium sensitization risk was higher for machinists (4.7%) and for persons reporting measured overexposure (7.4%, odds ratio 5.1); exposure beginning before 1970 (3.6%, odds ratio 2.7); consistent beryllium exposure (3.4%); and sawing (4.7%) or band sawing (6.0%) of beryllium metal. We conclude that both individual susceptibility to sensitization and exposure circumstances are important in developing disease.

Lead absorption in indoor firing range users.

To determine if users of indoor firing ranges may be at risk from lead exposure, we studied a law enforcement trainee class during three months of firearms instruction. Blood lead levels were obtained before training and at four-week intervals during training. Air lead levels were measured three times during instruction. Blood lead levels rose from a pre-training mean of 0.31 mumol/L to 2.47 mumol/L. Mean air lead levels were above 2,000 micrograms/m3, more than 40 times the Occupational Safety and Health Administration's standard of 50 micrograms/m3. Cumulative exposure to lead and the change in blood lead were positively correlated. Control measures need to be studied to determine their efficacy in decreasing or eliminating this health risk.

Yersinae isolated from wapiti (Cervus canadensis roosevelti).

Yersinia enterocolitica and Yersinia enterocolitica-like bacteria were isolated from 22 of 90 fecal samples taken from five herds of wapiti studied in northwestern California. The serotypes included: (5), (6), (11), (16), (2,19), (4,16) and (6,15). In one herd, all of the organisms were isolated from within a one hectare area. A significantly higher (p < .02) prevalence of isolations was obtained during April and May.

Listeria monocytogenes isolated from wapiti (Cervus canadensis roosevelti).

Serotypes 1 and 4 Listeria monocytogenes were isolated from 14 of 72 wapiti among four of five herds studied in northwestern California. More isolations of Listeria were made during the summer months than during the other months of the study from one of the herds. The pathogenicity of the strains varied with their ability to ferment xylose and rhamnose.