Customer exposure to gasoline vapors during refueling at service stations

Gasoline is a volatile complex mixture of hydrocarbon compounds that is easily vaporized during handling under normal conditions. Modern reformulated gasoline also contains oxygenates to enhance octane number and reduce ambient pollution. This study measured the difference in the exposure of customers to gasoline and oxygenate vapors during refueling in service stations with and without vapor recovery systems. Field measurements were carried out at two self-service stations. One was equipped with Stage I and the other with Stage II vapor recovery systems. At Stage I stations there is vapor recovery only during delivery from road tanker, and at Stage II stations additional vapor recovery during refueling. The exposure of 20 customers was measured at both stations by collecting air samples from their breathing zone into charcoal tubes during refueling with 95-octane reformulated gasoline. Each sample represented two consecutive refuelings. The samples were analyzed in the laboratory by gas chromatography using mass-selective detection for vapor components. The Raid vapor pressure of gasoline was 70 kPa and an oxygen content 2 wt%. Oxygenated gasoline contained 7 percent methyl tert-butyl ether (MtBE) and 5 percent methyl tert-amyl ether (MtAE). The geometric mean concentrations of hydrocarbons (C3-C11) in the customers' breathing zone was 85 mg/m3 (range 2.5-531 mg/m3) at the Stage I service station and 18 mg/m3 (range < 0.2-129 mg/m3) at the Stage II service station. The geometric mean of the exposure of customers to MtBE during refueling at the Stage I service station was 15.3 mg/m3 (range 1.8-74 mg/m3), and at the Stage II service station 3.4 mg/m3 (range 0.2-16 mg/m3). The differences in exposure were statistically significant (p < 0.05). The mean refueling times were 57 seconds (range 23-207) at the Stage I and 66 seconds (range 18-120) at the Stage II station. The measurements were done on consecutive days at the various service stations. The temperature ranged from 10 to 17 degrees C, and wind velocity was 2-4 m/s. The climatic conditions were very similar on the measurement days. Based on this study it was found that the Stage II vapor recovery system reduces gasoline emission considerably. The exposure level of customers at the Stage II station during refueling was circa 20-25 percent of the exposure at the Stage I service station when conditions were equal and no other confounding factors such as leaks or spills were present.     

Service station attendants' exposure to benzene and gasoline vapors.

Service station attendants' exposure to benzene, based on 85 TWA results at 7 stations, were well below 1 ppm except one exposure of 2.08 ppm. Short term exposures were 1.21 ppm or less over 15 minutes. Attendants' TWA exposures to total gasoline vapor were 114 ppm or less, with measured 15 minute exposures no higher than 100 ppm during actual filling operations. One station had vapor recovery nozzles; exposures here were below the detectable level (0.01 ppm benzene) on 10% more days than the next lowest station. Still, the magnitude of overall exposures and the degree of reduction indicate that vapor recovery is not needed to control exposures. Some attendants had consistently higher exposures than others. This is felt to be due to work practices, such as standing close to the fill opening, plus local wind conditions around the car as it is filled with gasoline.     

Psychological performance and long-term exposure to mercury vapors

In a cross-sectional study the psychological test performances of a group of 36 male chlorine-alkali workers were compared with the level of exposure to mercury and to the corresponding results of referents. The mercury exposure had lasted for at least 10 years and had been controlled by regular health examinations and urine analyses. Several dose indicators were calculated. The more heavily exposed workers performed more poorly on the verbal intelligence test (Similarities) than the referents did. Impairments in the memory tests showed a statistically significant correlation with the actual exposure level, especially with the actual concentration of mercury in blood. The monitoring of mercury in blood can be useful in health surveillance programs. The level of mercury in the air was calculated from the dose indicators. The results support the recommended exposure limit of 25 micrograms/m3 for metallic mercury vapor in the air as a level avoiding adverse effects in exposed workers.     

Asbestosis in a truck driver: a clinical case and analysis of the exposure]

The paper reports a case of asbestosis in a truck driver whose anamnesis, at first, revealed no evidence of previous exposure to asbestos, whether occupational or extra occupational. A pleuro-pulmonary fibrosis was discovered in 1987, following an episode of exudative pleurisy on the right side. The thickened pleura was then surgically removed. In the samples of pleuro-pulmonary fibroid tissue taken during the operation, typical asbestos bodies were demonstrated in optical microscopy. The analysis of possible exposure to asbestos that might not have been referred in the anamnesis revealed that in at least six widely used truck models (of which three were driven by the worker from 1958 to 1984), the presence of an asbestos winding around a manifold found on the bottom or on the side of the engine. In such trucks, the engine is inside the driver's cab, covered by a cowling set on the floor. Asbestos fibers could enter the driver's cab through a little window in the cowling or through outlets in the dashboard, carried by the airflow generated by the big fan at the back of the radiator and by the truck motion itself. The window or the outlets remained open during cold periods of the year to allow the air, warmed by the motor, to enter the driver's cab.     

Worker exposure to methanol vapors during cleaning of semiconductor wafers in a manufacturing setting

An exposure simulation was conducted to characterize methanol exposure of workers who cleaned wafers in quality control departments within the semiconductor industry. Short-term (15 min) and long-term (2-4 hr) personal and area samples (at distances of 1 m and 3-6 m from the source) were collected during the 2-day simulation. On the first day, 45 mL of methanol were used per hour by a single worker washing wafers in a 102 m(3) room with a ventilation rate of about 10 air changes per hour (ACH). Virtually all methanol volatilized. To assess exposures under conditions associated with higher productivity, on the second day, two workers cleaned wafers simultaneously, together using methanol at over twice the rate of the first day (95 mL/hr). On this day, the ventilation rate was halved (5 ACH). Personal concentrations on the first day averaged 60 ppm (SD = 46 ppm) and ranged from 10-140 ppm. On the second day, personal concentrations for both workers averaged 118 ppm (SD = 50 ppm; range: 64-270 ppm). Area concentrations measured on the first day at 1 m from the source and throughout the balance of the room averaged 29 ppm (SD = 19 ppm; range: 4-83 ppm) and 18 ppm (SD = 12 ppm; range: 3-42 ppm), respectively. As expected, area concentrations measured on the second day were higher than the first and averaged 73 ppm (SD = 25 ppm; range: 27-140 ppm) at 1 meter and 48 ppm (SD = 13 ppm; range: 21-67 ppm) throughout the balance of the room. The results of this simulation suggest that the use of methanol to clean semiconductor wafers without the use of local exhaust ventilation and with relatively low room ventilation rates is unlikely to result in worker exposures exceeding the current ACGIH(R) threshold limit value of 200 ppm. This study also confirmed prior studies suggesting that when a relatively volatile chemical is located within arm's length (near field), breathing zone concentrations will be about two- to threefold greater than the room concentration when the air exchange rate is 5-10 ACH.     

Evaluation of exposure to benzene vapour during the loading of petrol

Sherwood, R. J. (1972).Brit. J. industr. Med.,29, 65-69. Evaluation of exposure to benzene vapour during loading of petrol. The exposure of three workers to benzene vapour has been determined by personal air sampling, and has been related to their intake (assessed by sampling exhaled breath), and to their metabolism of benzene (evaluated from the concentration of phenol in urine.) The results obtained agree in general with those already published in the literature and with a preliminary experimental exposure undertaken as part of the development of techniques.

The two loaders who handled the loading arms were exposed to mean concentrations of 1·6 and 2·5 p.p.m. over the 5-hour period of loading. The probability of their exposure to concentrations greater than 25 p.p.m. was about 0·1 and 1%. The weigher working between the tracks was exposed to a mean concentration of 20 p.p.m. over the same period and had a total exposure of 114 p.p.m.-hour. Samples of exhaled breath taken at the end of work showed 0·14 and 0·18 p.p.m. benzene for the loaders and 0·84 p.p.m. for the weigher. The following morning the latter showed 0·19 p.p.m. Urine samples taken from the loaders at the end of work contained 12 and 25 mg/l total phenol and for the weigher 83 mg/l. The following morning the phenol was not above natural levels in the loaders' urine, and was 38 mg/l in a sample from the weigher.

It is suggested that any or all of the methods developed for this study could be used in conjunction with appropriate clinical studies to provide a more quantitative basis for determining the hazard of occupational exposure to benzene.

     

Characterizing potential exposure to the public from low-level radioactive waste transportation by truck

To address public concern about potential exposure to gamma radiation from legal-weight low-level radioactive waste truck shipments to the Nevada Test Site, a stationary, automated array of four pressurized ion chambers was established for trucks to pass through. Data were collected from 1,012 of the 2,260 trucks that transported low-level radioactive waste to the Nevada Test Site from February through December 2003. To avoid perception of biasing a potential exposure low, the maximum reading (muR per hour; muR h(-1)) from the array was assigned as the gross measurement value for each truck. [In this article, exposure measurements are reported as Roentgen (R), as this unit is consistent with the data readings of the measurement instruments and has been historically presented to public stakeholders. Subsequently, dose measurements are reported as Roentgen Equivalent Man (rem).] To calculate the "net exposure" for each truck, the average and standard deviation of the maximum background values during the corresponding 12-h period when the truck arrived were subtracted from the gross value. For 483 trucks (47.7%), calculated net exposure values were equal to or less than zero, indicating that the exposure from the truck was indistinguishable from background. An additional 206 trucks (20.4%) had calculated net exposure values ranging between 0.0 and 1.0 muR h(-1). Cumulative exposure scenarios appropriate for rural transportation routes to the Nevada Test Site were developed; however, these scenarios assumed the unlikely case that the same individual was exposed to all of the trucks on that route. Cumulative exposure values were dominated by a small percentage of the trucks with comparatively high values. In communities along transportation routes, the probability of an individual receiving a potential exposure from a single truck may be a more meaningful perspective.     

Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002

The destruction of the World Trade Center (WTC) in New York City on September 11, 2001, created a 16-acre debris field composed of pulverized and burning material significantly impacting air quality. Site cleanup began almost immediately. Cleanup workers were potentially exposed to airborne contaminants, including particulate matter, volatile organic compounds, and asbestos, at elevated concentrations. This article presents the results of the exposure assessment of one important group of WTC workers, truck drivers, as well as area monitoring that was conducted directly on site during October 2001 and April 2002. In cooperation with a local labor union, 54 drivers (October) and 15 drivers (April) were recruited on site to wear two monitors during their 12-hour work shifts. In addition, drivers were administered a questionnaire asking for information ranging from "first day at the site" to respirator use. Area monitoring was conducted at four perimeter locations during October and three perimeter locations during April. During both months, monitoring was also conducted at one location in the middle of the rubble. Contaminants monitored for included total dust (TD), PM10, PM2.5, and volatile organic compounds. Particle samples were analyzed for mass, as well as elemental and organic carbon content. During October, the median personal exposure to TD was 346 microg/m3. The maximum area concentration, 1742 microg/m3, was found in middle of the debris. The maximum TD concentration found at the perimeter was 392 microg/m3 implying a strong concentration gradient from the middle of debris outward. PM2.5/PM10 ratios ranged from 23% to 100% suggesting significant fire activity during some of the sampled shifts. During April, the median personal exposure to TD was 144 microg/m3, and the highest area concentration, 195 microg/m3, was found at the perimeter. During both months, volatile organic compounds concentrations were low.     

Physiological and environmental factors affecting biological monitoring of exposure to organic solvent vapors

A review of the literature was made on the physiological and environmental factors affecting pharmacokinetic behavior of organic solvent vapors in relation to biological monitoring of exposure to organic solvents. Among the physiological factors the importance is attached to body build (body weight and body fat content), sex, and physical activity. Environmental factors are centered on cigarette smoking, medications, coexistence of other solvents, dietary intake, and ethanol consumption with special emphasis of their effects on the hepatic metabolism of organic solvents.     

Respiratory effects of exposure to chlorine vapors during a swimming pool accident in a recreational center in Rome

When inhaled, chlorine is a highly irritating gas that can damage larger airways as well as distal lung structure. We examined the short-term respiratory effects of acute chlorine inhalation during a swimming pool accident. On October 22, 1998, an emission of chlorine vapours occurred in the chlorinating maintenance procedures room of a recreational center in Rome. A total of 282 subjects (134 children) inhaled hydrogen chloride and sodium hypochlorite. Most people received bronchodilators and cortisone at the emergency room; five children were hospitalised. A telephone follow-up was taken on 260 (92.2%) subjects to obtain information about duration of exposure (less than 3 minutes, 3-5 minutes, more than 5 minutes), intensity of exposure (not at all/a little, a fair amount, a lot), and acute respiratory symptoms. A total of 236 (90.7% of the target) individuals underwent clinical examinations, which took place 15-30 days after the accident. Lung function was measured in 184 people (82 children) after 15-30 days. A multiple linear regression was run to test the association between chlorine exposure and lung function, separately in adults and in children. Acute respiratory symptoms occurred among 66.7% adults and 71.6% children. The incidence rates were highest among those who had chronic respiratory disease and had a longer duration of exposure. In about 30% of the subjects, respiratory symptoms persisted 15-30 days after the accident. Lung function levels were reduced among those who reported high intensity of exposure in comparison to those who reported low exposure, both in children and in adults (forced expiratory volume in one second, FEV1, ml differences: -109 (CI 95%: -310, 93) and -275 (CI 95%: -510, -40). Given high prevalence of potential exposed people, findings from this study should alert public health authority about the possible clinical consequences.     

Exposure to vapors, gas, dust, or fumes: assessment by a single survey item compared to a detailed exposure battery and a job exposure matrix

BACKGROUND: Occupational exposure assessment often relies upon subject report. We examined the characteristics of self-reported exposure in respondents' longest held job to vapors, gas, dust, or fumes (VGDF) compared to other measures of exposure risk. METHODS: We analyzed data from 1,876 respondents from a national US population-based telephone survey designed to estimate the association between occupational factors and chronic disease of the airways. We tested a single VGDF item against responses to a 16-item battery assessing specific inhalation exposures and against a job exposure matrix (JEM). We analyzed all of these measures for their association with adult-onset asthma after excluding subjects with COPD or asthma with onset before age 18. RESULTS: VDGF (single item) was reported by 744 (40%) subjects; any of the 16 exposures by 899 (48%); and an intermediate or high exposure likelihood job by JEM was assigned to 682 (36%). The sensitivity of the VGDF item measured against the 16-item battery was 69%; the specificity was 88%; (classification agreement kappa=0.58); against the JEM classification the sensitivity was 64% and specificity 74% (kappa=0.37). The relative odds (OR) for adult-onset asthma associated with various measures of exposure were: VGDF, 1.7 (95% Confidence Interval [CI] 1.0-2.8; P=0.04); any of the 16 exposures, 1.6 (95% CI 1.0-2.7; P=0.06), and intermediate or high by JEM, 1.2 (0.7-2.1; P>0.50). CONCLUSIONS: A single VGDF survey item appears to delineate exposure risk at least as well as a multiple-item battery assessing such exposures; it has modest agreement with a JEM-based exposure categorization.     

Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission.     

Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery

Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from <0.001 to 2.9mg/m(3), and, in all but one case, resulted in concentrations below the current U.S. Occupational Safety and Health Administration's Permissible Exposure Limits and the American Conference of Governmental Industrial Hygienists' Threshold Limit Values. The arithmetic mean total dust concentration resulting from long-term personal samples was 0.31mg/m(3). The data presented here are the most complete set of its kind in the open literature, and are useful for understanding the potential exposures during solid catalyst handling activities at this petroleum refinery and perhaps other modern refineries during the timeframe examined.     

Assessment of exposure to pesticides during mixing/loading and spraying of tomatoes in the open field

Some evidence of exposure-response of metolachlor and pendimethalin for lung cancer and an association of metribuzin with risk of glioma have been reported. The primary objectives in this study were to evaluate exposure and occupational risk during mixing/loading of pesticides and during their application to tomatoes cultivated in open fields.

Sixteen farmers were sampled. Respiratory exposure was estimated by personal air sampling using fiberglass filters in a IOM device. Dermal exposure was assessed using skin pads and hand washing. Absorbed doses were estimated assuming 100% lung retention, and 50% or 10% skin absorption for metribuzin, and pendimethalin and metolachlor, respectively. The three pesticides were quantified by gas chromatography tandem mass spectrometry in all matrices. Metolachlor was used as a tracer of contamination of clothes and tractors unrelated to the exposure monitored.

Respiratory exposure to metribuzin, used in granular form, was on average more than one order of magnitude higher than exposure to pendimethalin, used in the form of microencapsulated liquid. The actual doses were 0.067–8.08 µg/kg bw, 0.420–12.6 µg/kg bw, and 0.003–0.877 µg/kg bw for pendimethalin, metribuzin, and metolachlor, respectively. Dermal exposure was about 88% of the actual dose for metribuzin and more than 95%, for pendimethalin and metolachlor. For risk assessment, the total absorbed doses (sum of respiratory and skin absorbed doses) were compared with the AOEL for each compound.

The actual and absorbed doses of the three pesticides were always lower than the acceptable operator exposure level (AOEL), which are reported to be 234 µg/kg bw, 20 µg/kg bw, and 150 µg/kg bw for pendimethalin, metribuzin, and metolachlor, respectively. In any case, personal protective equipment and spraying devices should be chosen with care to minimize exposure.