Exploring chainsaw operator occupational exposure to carbon monoxide in forestry

Exposure to carbon monoxide (CO) emitted by chainsaws can negatively impact health in forestry workers. This exploratory study measures CO concentration within the breathing zone of chainsaw operators during motor-manual operations, and discusses the potential influences on CO exposure levels. A CO monitoring instrument was paired with a concurrent video recording of task activities to enable correlation of exact working operations to critical exposure levels. Multiple streams of meteorological data were also collected from sensors worn by the eight professional tree fellers/log makers. Time-weighted averages were applied to investigate levels of CO exposure during a nominal 1-hr monitoring period. The differing task demands and environment were found to influence worker exposure to CO, supporting previous research. Pending further investigation, a number of possible actions are recommended to reduce observed high exposure levels and/or emission concentration.     

Simultaneous assessment of occupational exposures from multiple worker groups

The methods developed by Rappaport et al. [Ann. Occup. Hyg. 39 (1995) 469] and Lyles et al. [J. Agri. Bio. Environ. Stat. 2 (1997a) 64; Ann. Occup. Hyg. 41 (1997b) 63]) for assessing workplace exposures on a group-by-group basis are extended to allow for the simultaneous assessment of data from multiple worker groups within the same industry. These extended methods allow models to be fit simultaneously to data on all groups in a study, even when some of the groups might not contribute adequate information to be modeled separately. We assume that the exposures are log-normally distributed, and that they can be adequately modeled by a mixed effects regression model with parameters for exposure levels and for between- and within-worker variance components. Simultaneously analyzing data from multiple groups is only advantageous when at least one of these variance components can be assumed to be homogeneous across the groups. Here, we advocate testing an assumption of homogeneous within-worker variance components, sigma(2)(w,h), using a likelihood ratio test to choose between a full model (distinct sigma(2)(w,h) for each group) and a reduced model (common sigma(2)(w) across groups). We then develop a procedure, which is conditional on the results of the likelihood ratio test, for testing whether or not each group of workers is overexposed to the contaminant of interest. This modeling and testing procedure was applied to 39 different data sets, each containing data for multiple groups, from a wide variety of industries. For these data, the testing procedure generally resulted in the same conclusion regarding overexposure under both models, even in those data sets where the within-worker variance components appeared to be quite heterogeneous. We also conducted a small simulation study to estimate the significance level of the proposed testing procedure, and found that the significance levels tended to be adequately close to the specified nominal level when a likelihood ratio test with significance level of at least 0.01 was used as a preliminary test. Additionally, we make specific recommendations for designing studies and suggest a method for determining whether engineering and administrative controls or individual-level interventions would be of most benefit to an overexposed group of workers.     

Chickenpox ARDS in a health care worker following occupational exposure

A case is described of chickenpox acute respiratory distresssyndrome in an ambulance driver after the inter-hospital transferof a patient known to have chickenpox pneumonia. Following thisexposure, he neither avoided patient contact nor received varicellazoster immune globulin. He subsequently required 13 days ofventilatory support before making a full recovery. The casedescribed supports the contention that health care workers shouldbe screened by serology for immunity to chickenpox before patientcontact occurs, with subsequent vaccination of those who arenon-immune, when the vaccine becomes available.     

职业性接触抗癌药对护工的急性影响

1 病例报告 一位41岁在社区教学医院肿瘤楼层工作的护士,按医院要求,空戴防护服和手套,到厕所倒完便盆后约30min出现瘙痒,身上显现出皮疹.     

Acute effects from occupational exposure to antineoplastic drugs in a para-professional health care worker

BACKGROUND: While health risks from occupational exposure of nursing and pharmacy staff have been recognized, exposure of para-professional health care workers (HCW) has received little attention. METHODS: This case report describes a patient care assistant who developed allergic reactions subsequent to exposure to urine of oncology patients who had been treated with antineoplastics. RESULTS: The patient care assistant on two occasions developed a pruritic, disseminated rash shortly after emptying commodes containing the urine of oncology patients treated with Vincristine and Adriamycin (doxorubicin). CONCLUSIONS: Increased attention should be focused on the occupational exposures of para-professional HCWs to potentially hazardous antineoplastics.     

Media and secondhand smoke exposure: results from a national survey

OBJECTIVES: To investigate whether associations between anti-secondhand smoke (SHS) media, social cognitions about SHS, and home restrictions on smoking follow patterns observed in smoking behavior. METHODS: Based on a nationally representative sample of 2348 US adults drawn from the American Legacy Foundation's American Smoking and Health Survey, we tested relationships among scales of anti-SHS media, social cognitions, and home restrictions. RESULTS: We found anti-SHS media and SHS cognitions, as well as social cognitions and home restrictions, to be significantly associated. Social cognitions mediated the relationship between anti-SHS media and home restrictions. CONCLUSIONS: Previously observed relationships between media, social cognitions, and smoking also exist for SHS. Anti-SHS media campaigns to increase home restrictions may help to reduce SHS exposure.     

The Application of a new carbon disulfide exposure test in occupational health

Summary The commonly-used iodo-azide test (IAT) for exposure to carbon disulphide is compared with two new gaschromatographic (GLC) methods.The GLC methods are consistent with each other, but not consistent with the IAT.The urine values of 23 exposed and 6 non-exposed workers were compared with the results of the IAT and the two GLC methods.The conclusion was that GLC methods are better suited for measuring in urine at low exposure for qualitative purposes.     

Occupational and residential 60-Hz electromagnetic fields and high-frequency electric transients: exposure assessment using a new dosimeter

One problem that has limited past epidemiologic studies of cancer and exposure to extremely low-frequency (0-100 Hz) electric and magnetic fields has been the lack of adequate methods for assessing personal exposure to these fields. A new 60-Hz electromagnetic field dosimeter was tested to assess occupational and residential exposures of a group of electrical utility workers and a comparison background group over a 7-day period. Comparing work periods only, utility workers' exposures were significantly higher than background levels by a factor of about 10 for electric (E) and magnetic (B) fields and by a factor of 171 for high-frequency transient electric (HFTE) fields. When overall weekly time-weighted averages combining work and nonwork exposures were compared, ratios of the exposed to background groups were lower. B and HFTE exposure ratios remained statistically significant, with values of 3.5 and 58, respectively, whereas the electric field exposure ratio was no longer significant, with a value of 1.7. E-field exposures of the background group were the highest during the nonwork period, probably reflecting the use of electrical appliances at home. Residential E- and B-field exposures were in the same range as published results from other surveys, whereas occupational E-field exposures tended to be lower than exposures reported in other studies. The high variability associated with occupational exposures probably accounts for the latter discrepancy. Worker acceptance of wearing the dosimeter was good: 95% of participants found it to be of little or no inconvenience while at work. At home, 37% found the device to be inconvenient in its present form but would not object to wearing a slightly smaller and lighter dosimeter.     

Respirator use and protection from exposure to carbon monoxide

Investigations of the protective effect afforded by respirators in Baltimore firefighters are presented. The data indicates that the continuous use of respirators offers significant protection from exposure to carbon monoxide but that this protection is not absolute. A surprising finding is that the intermittent use of the face mask offers as little protection to the men as does non-use. These findings emphasize the difficulties in relying upon respiratory personal protective equipment for protection from exposure.     

1起急性一氧化碳职业中毒事故调查报告

目的调查事故原因,提出防范对策。方法采用现场职业卫生学调查。结果2名患者均直接接触一氧化碳。一氧化碳浓度在事故发生后5h仍高达20.0mg/m3。结论这是1起急性一氧化碳职业中毒事故。     

Mayak film dosimeter response studies, part iii: application to worker dose assessment

This paper describes the methods used to correct individual dosimeter readings for workers to obtain estimates of worker doses received at the Mayak Production Association (Mayak PA). Film dosimeters were used at Mayak PA for worker monitoring from 1948 until 1992. The method requires a determination of the relationship between the absorbed dose in film emulsion and the dose in air under calibration conditions, which is then extended to exposures in the actual radiation fields of the workplace. Corrections needed to account for actual workplace exposure conditions were determined by modeling with the Monte Carlo radiation transport computer code MCNP. Correction factors were developed to convert from dosimeter reading to a realistic worker dose. The method was applied as a basis for individual dose reconstruction using film dosimeters in realistic photon spectra and geometries at Mayak PA work areas.     

Incidence and causes of carbon monoxide intoxication: results of an epidemiologic survey in a French department.

The purpose of this study was to estimate the incidence, mortality, and causes of carbon monoxide intoxications in France. A survey was conducted in the department of the Hauts-de-Seine, which is representative of the French population. Data were collected through a headquarters that had direct contact with all department emergency organizations and to a technical laboratory. During the 3-y study, 735 cases that were related to 291 events were reported. Thirty-six patients died. The average incidence of carbon monoxide intoxications was 17.5 per 100,000 inhabitants. Poisoning was caused by fires in 36 events and by car exhausts in 12. For the remaining events, causes were determined as follows for 196: water heaters (57%), boiler (20.5%), coal stove (9%), brazier (4%), cooker (2%), heating device (1.5%), and miscellaneous (6%). The main mechanisms of intoxication were a defective device, poor ventilation, or poor evacuation of combustion gases. Carbon monoxide intoxication occurs frequently in France, and preventive actions are warranted.     

Environmental and occupational exposure to manganese: a multimedia assessment

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic additive used in Canada since 1976 as an anti-knock agent in unleaded gasoline. Its combustion leads to the emission of Mn oxides, especially Mn₃O₄. Since no study has assessed the potential risk of chronic exposure to low concentrations resulting from these emissions, the present investigation was undertaken to assess the level of environmental and occupational exposure of the human population. The multimedia exposure of two groups of workers (garage mechanics and blue-collar workers) potentially exposed to different levels of Mn from the combustion of MMT was assessed using personal air samplers, a dietary compilation, water samples at their places of residence, an epidemiological questionnaire and blood and hair samples. Results show that garage mechanics were exposed on average to higher atmospheric Mn at work (0.42 µg/m³) than the blue-collar workers (0.04 µg/m³). However, the contribution of atmospheric Mn to the total absorbed dose was less than 1%, and well below the standards estabished for occupational or environmental exposure; food contributes more than 95% of the multimedia dose. The average whole blood Mn concentrations were similar for the two groups (0.67–0.76 µg/100 ml) and fall within the normal adult range. The average hair Mn concentrations were significantly higher for the garage mechanics (0.66 µg/g) than for the blue-collar workers (0.39 µg/g). The contribution of exogenous Mn versus endogenous Mn is questioned. As judged by the governmental standards or criteria for occupational and non-occupational environments, the current Mn levels in food, water and air may not cause any problems for the workers.     

Tissue levels of mercury determined in a deceased worker after occupational exposure

Objectives: To examine mercury (Hg) and selenium (Se) levels in autopsy samples from a thermometer worker who had been exposed over a long period to, and monitored for, mercury vapor. Case report: Hg and Se levels were determined using radiochemical neutron activation analysis in a worker who had commited suicide 4 weeks after the end of 14 years of exposure and in an unexposed age-matched referent. Histochemical staining of cerebellum was performed according to the method of Danscher and Schrøder. Results: The Hg concentrations (wet weight) were 25?μg/g in the kidney cortex, 1.2?μg/g in the liver, 0.72?μg/g in the lung, 0.025?μg/g in the testis, and 0.014–0.018?μg/g in the cerebellum (gray matter, dentate nucleus, and white matter). The Se level in the kidney cortex was high, 4.6?μg/g, whereas the concentration detected in the other tissue samples was normal. Light microscopy of the cerebellum was normal, and no histochemical staining for mercury was observed. Autopsy samples from the referent showed low Hg and Se levels consistent with other reports. Conclusions: The observed kidney-Hg, which was 50–100 times higher than that occurring in the general population, is in agreement with previous sparse data from ongoing occupational exposure. The high Se level detected in the kidney indicates coaccumulation with mercury. The low Hg concentration found in the cerebellum was unexpected, since some reports have shown much higher brain-Hg long after the cessation of exposure.     

Exacerbation of coronary artery disease by occupational carbon monoxide exposure: a report to two fatalities and a review of the literature

The recent deaths of two workers with coronary artery disease (CAD) following exposure to carbon monoxide (CO) at work reinforced our appreciation of the hazard of this exposure to individuals with preexisting heart disease. Carbon monoxide acts to precipitate ischemia by reducing oxygen delivery to the myocardium. Animal and in vitro experiments suggest that CO may accelerate the development of atherosclerosis, particularly if exposure is in association with other risk factors. Thus, persons with known CAD who are exposed to CO at work are at risk for both the acceleration of the course of the underlying disease and for precipitation of acute ischemia or infarction following excessive exposure. Particular attention should be given to control of CO exposures in light of this hazard. For various reasons, preplacement evaluations or other job selection procedures do not adequately address his hazard. In view of the high prevalence of CAD in the U.S. and the high frequency of workplace exposure to CO, particular attention should be given to control of CO exposure through industrial hygiene measures.     

MRI and neuropsychological correlates of carbon monoxide exposure: a case report

A 45-year-old woman experienced long-term, chronic exposure to carbon monoxide in the restaurant kitchen where she was employed as a cook. After returning to the restaurant after 5 days off work, she noticed that her symptoms returned immediately; she then aired out the room and called the gas company. Approximately 6 hr after a leak was detected, the patient went to the hospital, where her carboxyhemoglobin was found to be within normal limits and results of a neurologic examination were described as normal. Based on her symptoms, the patient believed she had been exposed to CO for at least 1 year before the leak was discovered. Initially, she experienced flu-like symptoms, which eventually resolved. At the time of her first neuropsychological evaluation (17 months after the exposure was identified), her persisting complaints included difficulties in reading, writing, speaking and word retrieval. The test results were consistent with secondary frontal lobe dysfunction associated with subcortical disorders such as those seen after CO exposure. Results of a subsequent neuropsychological examination (29 months postexposure) showed slight improvement in performance, but her performance was still consistent with mild frontal/subcortical dysfunction. Although the initial screening of a brain magnetic resonance image (MRI) performed 15 months after the exposure was interpreted as being within normal limits, two subsequent blind reviews of the same scans identified multiple bilateral lesions in the basal ganglia, which were consistent with chronic CO exposure. We present this case as an example of the utility of MRI and neuropsychological examinations in detecting central nervous system dysfunction secondary to CO exposure.     

Birth outcomes and prenatal exposure to ozone, carbon monoxide, and particulate matter: results from the Children's Health Study

Exposures to ambient air pollutants have been associated with adverse birth outcomes. We investigated the effects of air pollutants on birth weight mediated by reduced fetal growth among term infants who were born in California during 1975-1987 and who participated in the Children's Health Study. Birth certificates provided maternal reproductive history and residence location at birth. Sociodemographic factors and maternal smoking during pregnancy were collected by questionnaire. Monthly average air pollutant levels were interpolated from monitors to the ZIP code of maternal residence at childbirth. Results from linear mixed-effects regression models showed that a 12-ppb increase in 24-hr ozone averaged over the entire pregnancy was associated with 47.2 g lower birth weight [95% confidence interval (CI), 27.4-67.0 g], and this association was most robust for exposures during the second and third trimesters. A 1.4-ppm difference in first-trimester carbon monoxide exposure was associated with 21.7 g lower birth weight (95% CI, 1.1-42.3 g) and 20% increased risk of intrauterine growth retardation (95% CI, 1.0-1.4). First-trimester CO and third-trimester O3 exposures were associated with 20% increased risk of intrauterine growth retardation. A 20-microg/m3 difference in levels of particulate matter < or = 10 microm in aerodynamic diameter (PM10) during the third trimester was associated with a 21.7-g lower birth weight (95% CI, 1.1-42.2 g), but this association was reduced and not significant after adjusting for O3. In summary, O3 exposure during the second and third trimesters and CO exposure during the first trimester were associated with reduced birth weight.     

An occupational exposure assessment of a perfluorooctanesulfonyl fluoride production site: biomonitoring

This investigation randomly sampled a fluorochemical manufacturing employee population to determine the distribution of serum fluorochemical levels according to employees' jobs and work areas. Previous analyses of medical surveillance data have not shown significant associations between fluorochemical production employees' clinical chemistry and hematology tests and their serum PFOS and perfluorooctanoate (PFOA, C(7)F(15)COO(-)) concentrations, but may have been subject to nonparticipation bias. A random sample of the on-site film plant employee population, where fluorochemicals are not produced, determined their serum concentrations also. Of the 232 employees randomly selected for serum sampling, 186 (80%) employees participated (n=126 chemical plant; n=60 film plant). Sera samples were extracted using an ion-pairing extraction procedure and were quantitatively analyzed for seven fluorochemicals using high-pressure liquid chromatography electrospray tandem mass spectrometry methods. Geometric means (in parts per million) and 95% confidence intervals (in parentheses) of the random sample of 126 chemical plant employees were: PFOS 0.941 (0.787-1.126); PFOA 0.899 (0.722-1.120); perfluorohexanesulfonate 0.180 (0.145-0.223); N-ethyl perfluorooctanesulfonamidoacetate 0.008 (0.006-0.011); N-methyl perfluorooctanesulfonamidoacetate 0.081 (0.067-0.098); perfluorooctanesulfonamide 0.013 (0.009-0.018); and perfluorooctanesulfonamidoacetate 0.022 (0.018-0.029). These geometric means were approximately one order of magnitude higher than those observed for the film plant employees.