The intensity and duration of occupational noise exposure and cardiovascular disease in the United States: a nationally representative study, 2015 to 2020.

OBJECTIVES: Occupational noise exposure may be associated with an increased risk of cardiovascular disease (CVD). Yet the findings are inconclusive. This study aimed to examine the association between self-reported occupational noise exposure and CVD (using a broad composite case definition and by each condition) and identify how these associations vary with the intensity and duration of noise exposure, and combinations thereof. METHODS: This cross-sectional study included a nationally representative sample (n = 6,266) from the National Health and Nutrition Examination Survey (2015 to 2020), aged 20 and greater, in the United States. Survey-weighted logistic regression models were constructed from multiple imputed datasets. RESULTS: Relative to the unexposed, the adjusted odds ratio (95% confidence interval) of composite CVD was 1.33 (1.05 to 1.67) among the noise-exposed population, and ranged from 1.23 to 1.56 when examining CVD conditions separately. The odds ratios of composite CVD were 1.43 (1.06 to 1.93), 1.43 (1.04 to 1.95), and 1.51 (1.03 to 2.21) among those who had noise exposure with very loud intensity of any duration, with duration ≥10 years at any intensity, and with a combination of very loud noise ≥10 years, respectively, compared to those unexposed. CONCLUSIONS: Increased risk of CVD is associated with occupational noise exposure, particularly at higher intensities and longer durations. Policies and interventions for noise mitigation at workplaces are warranted, targeting individuals with chronic exposure to high-level noise.

Developing wipe sampling strategy guidance for assessing environmental contamination of antineoplastic drugs.

Surveillance for environmental contamination of antineoplastic drugs has been recommended by authoritative bodies such as the United States Pharmacopeia and the National Association of Pharmacy Regulatory Authorities. Clear guidance is needed on how to develop sampling strategies that align with surveillance objectives efficiently and effectively. We conducted a series of simulations using previously collected surveillance data from nine cancer treatment centers to evaluate different sampling strategies. We evaluated the impact of sampling 2, 5, 10, or 20 surfaces, at monthly, quarterly, semi-annual, and annual frequencies, while employing either a random or sentinel surface selection strategy to assess contamination by a single antineoplastic drug (AD) or by a panel of three ADs. We applied two different benchmarks: a binary benchmark of above or below the limit of detection and AD-specific hygienic guidance values, based on 90th percentile values as quantitative benchmarks. The use of sentinel surfaces to evaluate a three-drug panel relative to 90th percentile hygienic guidance values (HGVs) resulted in the most efficient and effective surveillance strategy.

Diesel Engine Exhaust Exposure in the Ontario Civil Infrastructure Construction Industry.

OBJECTIVES: Diesel engine exhaust (DEE) is a known lung carcinogen and a common occupational exposure in Canada. The use of diesel-powered equipment in the construction industry is particularly widespread, but little is known about DEE exposures in this work setting. The objective of this study was to determine exposure levels and identify and characterize key determinants of DEE exposure at construction sites in Ontario. METHODS: Elemental carbon (EC, a surrogate of DEE exposure) measurements were collected at seven civil infrastructure construction worksites and one trades training facility in Ontario using NIOSH method 5040. Full-shift personal air samples were collected using a constant-flow pump and SKC aluminium cyclone with quartz fibre filters in a 37-mm cassette. Exposures were compared with published health-based limits, including the Dutch Expert Committee on Occupational Safety (DECOS) limit (1.03 µg m-3 respirable EC) and the Finnish Institute of Occupational Health (FIOH) recommendation (5 µg m-3 respirable EC). Mixed-effects linear regression was used to identify determinants of EC exposure. RESULTS: In total, 149 EC samples were collected, ranging from <0.25 to 52.58 µg m-3 with a geometric mean (GM) of 3.71 µg m-3 [geometric standard deviation (GSD) = 3.32]. Overall, 41.6% of samples exceeded the FIOH limit, mostly within underground worksites (93.5%), and 90.6% exceeded the DECOS limit. Underground workers (GM = 13.20 µg m-3, GSD = 1.83) had exposures approximately four times higher than below grade workers (GM = 3.56 µg m-3, GSD = 1.94) and nine times higher than above ground workers (GM = 1.49 µg m-3, GSD = 1.75). Training facility exposures were similar to above ground workers (GM = 1.86 µg m-3, GSD = 4.12); however, exposures were highly variable. Work setting and enclosed cabins were identified as the key determinants of exposure in the final model (adjusted R2 = 0.72, P < 0.001). The highest DEE exposures were observed in underground workplaces and when using unenclosed cabins. CONCLUSIONS: This study provides data on current DEE exposure in Canadian construction workers. Most exposures were above recommended health-based limits, albeit in other jurisdictions, signifying a need to further reduce DEE levels in construction. These results can inform a hazard reduction strategy including targeted intervention/control measures to reduce DEE exposure and the burden of occupational lung cancer.

Break-even Analysis of Respirable Crystalline Silica (RCS) Exposure Interventions in the Construction Sector.

OBJECTIVE: We investigated long-term economic impacts of respirable crystalline silica (RCS) removal interventions in the construction at the societal level. METHODS: We estimated costs and benefits of two RCS exposure interventions, use of "respirators" and "wet method," over a 30-year time period. We identified economic impacts of the interventions under four different scenarios. RESULTS: Under current practices, we estimated that approximately 125 lung cancer cases attributable to RCS exposure would arise in 2060. Under the full exposure removal scenario, we estimated there would be 53 new cases. Over the 30-year time period, the estimated cumulative averted cases are 787 and 482 for respirators and wet method, respectively, which amount to net benefits of $422.13 and $394.92 million. CONCLUSIONS: Findings provide important information for policymakers seeking to reduce the economic burden of occupational lung cancer in society.

Economic evaluation of interventions to reduce solar ultraviolet radiation (UVR) exposure among construction workers.

Solar ultraviolet radiation is one of the most common occupational carcinogens in Canada and is responsible for approximately 5,556 non-melanoma skin cancers per year. A large part of these cases are preventable by reducing solar ultraviolet radiation exposure. In this study, investigators estimated the potential economic impacts of different solar ultraviolet radiation reduction interventions among construction workers, as they are one of the largest at-risk occupational groups. Investigators performed an economic evaluation from a societal perspective, by comparing incremental costs in relation to incremental benefits achieved by two interventions-use of personal protective equipment by all exposed individuals and use of shade structure wherever and whenever feasible. Interventions costs were estimated for 2020-2050, and benefits with a 10-year delay, i.e., for the period 2030-2060. Economic evaluation estimates were reported by intervention costs, total costs of non-melanoma skin cancers cases averted, incremental cost per avert case, return on investment, and the break-even point. Various sensitivity analyses were undertaken with key parameters. Our findings indicate that if the rising trend of incidence continues, cases will be double in 2060, whereas by using personal protective equipment or shade structure, with the best-case scenario of full ultraviolet radiation removal, would result in 6,034 and 2,945 cases averted over 30 years, respectively. This translates into a total of $38.0 and $20.5 million of averted costs (all monetary values represented in 2017 Canadian dollars). Under this scenario investigators expect that by 2060, for every dollar invested in personal protective equipment and shade structures, $0.49 and $0.35 will be returned, respectively. Findings also suggested that under a conservative scenario, prevention of non-melanoma skin cancer cases by personal protective equipment and shade structures resulted in $5,812 and $7,355 incremental costs, respectively, over the 30-year period. This study provides important insights for decision makers about the potential impacts of solar ultraviolet radiation reduction interventions in the construction sector and other sectors with substantial outdoor work. Our estimates also can raise awareness of the importance of solar ultraviolet radiation reduction interventions.

Spatial and Temporal Variability in Antineoplastic Drug Surface Contamination in Cancer Care Centers in Alberta and Minnesota.

The health risks of exposure to antineoplastic drugs (ADs) are well established, and healthcare professionals can be exposed while caring for cancer patients receiving AD therapy. Studies conducted worldwide over the past two decades indicate continuing widespread surface contamination by ADs. No occupational exposure limits have been established for ADs, but concerns over exposures have led to the development of guidelines, such as United States Pharmacopeia (USP) General Chapter <800> Hazardous Drugs-Handling in Healthcare. While recommending regular surveillance for surface contamination by ADs these guidelines do not provide guidance on sampling strategies. Better characterization of spatial and temporal variability of multidrug contamination would help to inform such strategies. We conducted surface-wipe monitoring of nine cancer care centers in Alberta, Canada and Minnesota, USA, with each center sampled eight times over a 12-month period. Twenty surfaces from within pharmacy and drug administration areas were sampled, and 11 drugs were analyzed from each wipe sample. Exposure data were highly left-censored which restricted data analysis; we examined prevalence of samples above limit of detection (LOD), and used the 90th percentile of the exposure distribution as a measure of level of contamination. We collected 1984 wipe samples over a total of 75 sampling days resulting in 21 824 observations. Forty-five percent of wipe samples detected at least one drug above the LOD, but only three of the drugs had more than 10% of observations above the LOD: gemcitabine (GEM) (24%), cyclophosphamide (CP) (16%), and paclitaxel (13%). Of 741 wipe samples with at least one drug above LOD, 60% had a single drug above LOD, 19% had two drugs, and 21% had three drugs or more; the maximum number of drugs found above LOD on one wipe was 8. Surfaces in the compounding area of the pharmacy and in the patient area showed the highest prevalence of samples above the LOD, including the compounding work surface, drug fridge handle, clean room cart, passthrough tray, and hazardous drug room temperature storage, the IV pump keypad, patient washroom toilet handle, patient washroom door handle, nurses' storage shelf/tray, and patient side table. Over the course of the study, both 90th percentiles and prevalence above LOD varied without clear temporal patterns, although some centers appeared to show decreasing levels with time. Within centers, the degree of variability was high, with some centers showing changes of two to three orders of magnitude in the 90th percentile of drug concentrations month to month. A clear difference was observed between the six centers located in Alberta and the three in Minnesota, with Minnesota centers having substantially higher percentages of samples above the LOD for CP and GEM. Other factors that were associated with significant variability in exposures were drug compounding volume, size of center, number of patients seen, and age of the center. We hope that demonstrating variability associated with drug, surface, clinic-factors, and time will aid in a better understanding of the nature of AD contamination, and inform improved sampling strategies.

Garnet sand reveals rock recycling processes in the youngest exhumed high- and ultrahigh-pressure terrane on Earth.

Rock recycling within the forearcs of subduction zones involves subduction of sediments and hydrated lithosphere into the upper mantle, exhumation of rocks to the surface, and erosion to form new sediment. The compositions of, and inclusions within detrital minerals revealed by electron microprobe analysis and Raman spectroscopy preserve petrogenetic clues that can be related to transit through the rock cycle. We report the discovery of the ultrahigh-pressure (UHP) indicator mineral coesite as inclusions in detrital garnet from a modern placer deposit in the actively exhuming Late Miocene-Recent high- and ultrahigh-pressure ((U)HP) metamorphic terrane of eastern Papua New Guinea. Garnet compositions indicate the coesite-bearing detrital garnets are sourced from felsic protoliths. Carbonate, graphite, and CO2 inclusions also provide observational constraints for geochemical cycling of carbon and volatiles during subduction. Additional discoveries include polyphase inclusions of metastable polymorphs of SiO2 (cristobalite) and K-feldspar (kokchetavite) that we interpret as rapidly cooled former melt inclusions. Application of elastic thermobarometry on coexisting quartz and zircon inclusions in six detrital garnets indicates elastic equilibration during exhumation at granulite and amphibolite facies conditions. The garnet placer deposit preserves a record of the complete rock cycle, operative on <10-My geologic timescales, including subduction of sedimentary protoliths to UHP conditions, rapid exhumation, surface uplift, and erosion. Detrital garnet geochemistry and inclusion suites from both modern sediments and stratigraphic sections can be used to decipher the petrologic evolution of plate boundary zones and reveal recycling processes throughout Earth's history.

A scoping review to identify strategies that work to prevent four important occupational diseases.

BACKGROUND: Despite being largely preventable, many occupational diseases continue to be highly prevalent and extremely costly. Effective strategies are required to reduce their human, economic, and social impacts. METHODS: To better understand which approaches are most likely to lead to progress in preventing noise-related hearing loss, occupational contact dermatitis, occupational cancers, and occupational asthma, we undertook a scoping review and consulted with a number of key informants. RESULTS: We examined a total of 404 articles and found that various types of interventions are reported to contribute to occupational disease prevention but each has its limitations and each is often insufficient on its own. Our principal findings included: legislation and regulations can be an effective means of primary prevention, but their impact depends on both the nature of the regulations and the degree of enforcement; measures across the hierarchy of controls can reduce the risk of some of these diseases and reduce exposures; monitoring, surveillance, and screening are effective prevention tools and for evaluating the impact of legislative/policy change; the effect of education and training is context-dependent and influenced by the manner of delivery; and, multifaceted interventions are often more effective than ones consisting of a single activity. CONCLUSIONS: This scoping review identifies occupational disease prevention strategies worthy of further exploration by decisionmakers and stakeholders and of future systematic evaluation by researchers. It also identified important gaps, including a lack of studies of precarious workers and the need for more studies that rigorously evaluate the effectiveness of interventions.

The impact of night shift work on breast cancer: Results from the Burden of Occupational Cancer in Canada Study.

BACKGROUND: We estimated the proportion and number of female breast cancer cases in Canada attributable to night shift work, a probable cause of breast cancer. METHODS: Levin's equation was used to calculate population attributable fractions (PAFs) among Canadian women who ever worked night/rotating shifts from 1961 to 2000, accounting for labor turnover and survival to the year 2011. The calculated PAFs were applied to 2011 Canadian breast cancer incidence statistics to obtain the number of attributable cases. RESULTS: Approximately 1.5 million women ever worked night/rotating shifts during 1961-2000 and survived to 2011. The PAFs ranged from 2.0% (95% confidence interval [CI]: 1.4-6.2) to 5.2% (95% CI: 3.7-13.6), and 470 to 1200 incident breast cancer cases in 2011 were likely due to shift work, of which 38% would have been diagnosed among women in health-related occupations. CONCLUSIONS: More research is needed to increase the certainty of this association, but current evidence supports workplace-based prevention.

The current burden of cancer attributable to occupational exposures in Canada.

Exposure to occupational carcinogens is often overlooked as a contributor to the burden of cancer. To estimate the proportion of cancer cases attributable to occupational exposure in Canada in 2011, exposure prevalence and levels of 44 carcinogens were informed by data from the Canadian carcinogen exposure surveillance project (CAREX Canada). These were used with Canadian Census (between 1961 and 2011) and Labour Force Survey (annual surveys between 1976 and 2013) data to estimate the number of workers ever exposed to occupational carcinogens. Risk estimates of the association between each carcinogen and cancer site were selected mainly from published literature reviews. Population attributable risks were estimated using Levin's equation and applied to the 2011 cancer statistics from the Canadian Cancer Registry. It is estimated that 15.5 million Canadians alive in 2011 were exposed, during at least one year between 1961 and 2001, to at least one carcinogen in the workplace. Overall, we estimated that in 2011, between 3.9% (95% CI: 3.1%-8.1%) and 4.2% (95% CI: 3.3%-8.7%) of all incident cases of cancer were due to occupational exposure, corresponding to lower and upper numbers of 7700-21,800 cases. Five of the cancer sites - mesothelioma, non-melanoma skin cancer, lung, female breast, and urinary bladder - account for a total of 7600 to 21,200 cancers attributable to occupational exposures such as solar radiation, asbestos, diesel engine exhaust, crystalline silica, and night shift work. Our study highlights cancer sites and occupational exposures that need recognition and efforts by all stakeholders to avoid preventable cancers in the future.

Expostats: A Bayesian Toolkit to Aid the Interpretation of Occupational Exposure Measurements.

INTRODUCTION: Interpretation of exposure measurements has evolved into a framework based on the lognormal distribution. Most available practical tools are based on traditional frequentist statistical procedures that do not satisfactorily account for censored data and are not amenable to simple probabilistic risk statements. Bayesian methods offer promising solutions to these challenges. Such methods have been proposed in the literature but are not widely and freely available to practitioners. METHODS: A set of computer applications were developed aimed at answering typical inferential questions that are important to occupational health practitioners: Is a group of workers compliant with an occupational exposure limit? Are some individuals within this group likely to experience substantially higher exposure than its average member? How does an intervention influence the distribution of exposures? These questions were addressed using Bayesian models, simultaneously accounting for left, right, and interval-censored data with multiple censoring points. The models are estimated using the JAGS Gibbs sampler called through the R statistical package. RESULTS: The Expostats toolkit is freely available from www.expostats.ca as four tools accessible through a Web application, an offline standalone application or algorithms. The tools include a variety of calculations and graphical outputs useful according to current practices in analysis and interpretation of exposure measurements collected by occupational hygienists. Tool1 and its simplified version Tool1 Express focus on inferences from data from a similarly exposed group. Tool2 evaluates within- and between-worker components of variability, as well as the probability that an individual worker might be overexposed. Tool3 compares exposure data across groups, e.g. evaluates the effect of an intervention. Uncertainty management includes the calculation of credible intervals and produces probabilistic statements about the exposure metrics (e.g. probability that over 5% of exposures are above a limit). DISCUSSION: Expostats is the first freely available toolkit that leverages the flexibility of Bayesian analysis to perform an extensive list of calculations recommended in several international guidelines on the practice of occupational hygiene.

Development of Quantitative Estimates of Wood Dust Exposure in a Canadian General Population Job-Exposure Matrix Based on Past Expert Assessments.

Objectives: The CANJEM general population job-exposure matrix summarizes expert evaluations of 31 673 jobs from four population-based case-control studies of cancer conducted in Montreal, Canada. Intensity in each CANJEM cell is represented as relative distributions of the ordinal (low, medium, high) ratings of jobs assigned by the experts. We aimed to apply quantitative concentrations to CANJEM cells using Canadian historical measurements from the Canadian Workplace Exposure Database (CWED), taking exposure to wood dust as an example. Methods: We selected 5170 personal and area wood dust measurements from 31 occupations (2011 Canadian National Occupational Classification) with a non-zero exposure probability in CANJEM between 1930 and 2005. The measurements were taken between 1981 and 2003 (median 1989). A Bayesian hierarchical model was applied to the wood dust concentrations with occupations as random effects, and sampling duration, year, sample type (area or personal), province, and the relative proportion of jobs exposed at medium and high intensity in CANJEM cells as fixed effects. Results: The estimated geometric mean (GM) concentrations for a CANJEM cell with all jobs exposed at medium or high intensity were respectively 1.3 and 2.4 times higher relative to a cell with all jobs at low intensity. An overall trend of -3%/year in exposure was observed. Applying the model estimates to all 198 cells in CANJEM with some exposure assigned by the experts, the predicted 8-hour, personal wood dust GM concentrations by occupation for 1989 ranged from 0.48 to 1.96 mg m-3. Conclusions: The model provided estimates of wood dust concentrations for any CANJEM cell with exposure, applicable for quantitative risk assessment at the population level. This framework can be implemented for other agents represented in both CANJEM and CWED.

Priority Setting for Occupational Cancer Prevention.

BACKGROUND: Selecting priority occupational carcinogens is important for cancer prevention efforts; however, standardized selection methods are not available. The objective of this paper was to describe the methods used by CAREX Canada in 2015 to establish priorities for preventing occupational cancer, with a focus on exposure estimation and descriptive profiles. METHODS: Four criteria were used in an expert assessment process to guide carcinogen prioritization: (1) the likelihood of presence and/or use in Canadian workplaces; (2) toxicity of the substance (strength of evidence for carcinogenicity and other health effects); (3) feasibility of producing a carcinogen profile and/or an occupational estimate; and (4) special interest from the public/scientific community. Carcinogens were ranked as high, medium or low priority based on specific conditions regarding these criteria, and stakeholder input was incorporated. Priorities were set separately for the creation of new carcinogen profiles and for new occupational exposure estimates. RESULTS: Overall, 246 agents were reviewed for inclusion in the occupational priorities list. For carcinogen profile generation, 103 were prioritized (11 high, 33 medium, and 59 low priority), and 36 carcinogens were deemed priorities for occupational exposure estimation (13 high, 17 medium, and 6 low priority). CONCLUSION: Prioritizing and ranking occupational carcinogens is required for a variety of purposes, including research, resource allocation at different jurisdictional levels, calculations of occupational cancer burden, and planning of CAREX-type projects in different countries. This paper outlines how this process was achieved in Canada; this may provide a model for other countries and jurisdictions as a part of occupational cancer prevention efforts.

Burden of lung cancer attributable to occupational diesel engine exhaust exposure in Canada.

OBJECTIVE: To estimate the population attributable fraction (PAF) and number of incident and fatal lung cancers in Canada from occupational exposure to diesel engine exhaust (DEE). METHODS: DEE exposure prevalence and level estimates were used with Canadian Census and Labour Force Survey data to model the exposed population across the risk exposure period (REP, 1961-2001). Relative risks of lung cancer were calculated based on a meta-regression selected from the literature. PAFs were calculated using Levin's equation and applied to the 2011 lung cancer statistics obtained from the Canadian Cancer Registry. RESULTS: We estimated that 2.4% (95% CI 1.6% to 6.6%) of lung cancers in Canada are attributable to occupational DEE exposure, corresponding to approximately 560 (95% CI 380 to 1570) incident and 460 (95% CI 310 to 1270) fatal lung cancers in 2011. Overall, 1.6 million individuals alive in 2011 were occupationally exposed to DEE during the REP, 97% of whom were male. Occupations with the highest burden were underground miners, truck drivers and mechanics. Half of the attributable lung cancers occurred among workers with low exposure. CONCLUSIONS: This is the first study to quantify the burden of lung cancer attributable to occupational DEE exposure in Canada. Our results underscore a large potential for prevention, and a large public health impact from occupational exposure to low levels of DEE.

Prevalence of Hazardous Occupational Noise Exposure, Hearing Loss, and Hearing Protection Usage Among a Representative Sample of Working Canadians.

OBJECTIVE: The aim of this study was to estimate the prevalence of hearing loss (HL), self-reported occupational noise exposure, and hearing protection usage among Canadians. METHODS: In-person household interviews were conducted with 3666 participants, aged 16 to 79 years (1811 males) with 94% completing audiometry and distortion-product otoacoustic emission (DPOAE) evaluations. Occupational noise exposure was defined as hazardous when communicating with coworkers at an arm's length distance required speaking in a raised voice. RESULTS: An estimated 42% of respondents reported hazardous occupational noise exposure; 10 years or more was associated with HL regardless of age, sex or education. Absent DPOAEs, tinnitus, and the Wilson audiometric notch were significantly more prevalent in hazardous workplace noise-exposed workers than in nonexposed. When mandatory, 80% reported wearing hearing protection. CONCLUSIONS: These findings are consistent with other industrialized countries, underscoring the need for ongoing awareness of noise-induced occupational HL.

CAREX Canada: an enhanced model for assessing occupational carcinogen exposure.

OBJECTIVES: To estimate the numbers of workers exposed to known and suspected occupational carcinogens in Canada, building on the methods of CARcinogen EXposure (CAREX) projects in the European Union (EU). METHODS: CAREX Canada consists of estimates of the prevalence and level of exposure to occupational carcinogens. CAREX Canada includes occupational agents evaluated by the International Agency for Research on Cancer as known, probable or possible human carcinogens that were present and feasible to assess in Canadian workplaces. A Canadian Workplace Exposure Database was established to identify the potential for exposure in particular industries and occupations, and to create exposure level estimates among priority agents, where possible. CAREX EU data were reviewed for relevance to the Canadian context and the proportion of workers likely to be exposed by industry and occupation in Canada was assigned using expert assessment and agreement by a minimum of two occupational hygienists. These proportions were used to generate prevalence estimates by linkage with the Census of Population for 2006, and these estimates are available by industry, occupation, sex and province. RESULTS: CAREX Canada estimated the number of workers exposed to 44 known, probable and suspected carcinogens. Estimates of levels of exposure were further developed for 18 priority agents. Common exposures included night shift work (1.9 million exposed), solar ultraviolet radiation exposure (1.5 million exposed) and diesel engine exhaust (781 000 exposed). CONCLUSIONS: A substantial proportion of Canadian workers are exposed to known and suspected carcinogens at work.

Exposed! Or not? The diminishing record of workplace exposure in Canada.

The Canadian Workplace Exposure Database (CWED) is the first of its kind in Canada. It was originally developed in 2008 by the Canadian Carcinogen Exposure project (CAREX Canada) to assist in estimating worker exposures to carcinogens across the country.Following the CWED's establishment, all Canadian federal and provincial agencies responsible for administering occupational health and safety regulation were surveyed to obtain a clearer picture of the quantity and quality of regulatory exposure data available. This revealed troubling reductions in exposure measurement collection, retention, and centralization by these agencies in recent years.Such trends will limit access to workplace exposure measurements for federal and provincial regulatory agencies as well as health researchers. Workplace exposure databases are used around the world for a variety of important purposes, such as identifying hazardous workplaces and workers at risk, assessing temporal-spatial trends, setting priorities for prevention, and informing epidemiological research.Efforts are underway to preserve historical data and promote prospective collection, however future success of the CWED will require collaboration and long-term vision on the part of those responsible for collecting workplace exposure measurements in Canada.

Occupational exposures to antineoplastic drugs and ionizing radiation in Canadian veterinary settings: findings from a national surveillance project.

OBJECTIVES: Although veterinary workers may encounter various occupational health hazards, a national characterization of exposures is lacking in Canada. This study used secondary data sources to identify veterinary exposure prevalence for ionizing radiation and antineoplastic agents, as part of a national surveillance project. METHODS: For ionizing radiation, data from the Radiation Protection Bureau of Health Canada were used to identify veterinarians and veterinary technicians monitored in 2006. This was combined with Census statistics to estimate a prevalence range and dose levels. For antineoplastic agents, exposure prevalence was estimated using statistics on employment by practice type and antineoplastic agent usage rates, obtained from veterinary licensing bodies and peer-reviewed literature. RESULTS: In 2006, 7,013 (37% of all) Canadian veterinary workers were monitored for ionizing radiation exposure. An estimated 3.3% to 8.2% of all veterinarians and 2.4% to 7.2% of veterinary technicians were exposed to an annual ionizing radiation dose above 0.1 mSv, representing a total of between 536 and 1,450 workers. All monitored doses were below regulatory limits. For antineoplastic agents, exposure was predicted in up to 5,300 (23%) of all veterinary workers, with an estimated prevalence range of 22% to 24% of veterinarians and 20% to 21% of veterinary technicians. CONCLUSION: This is the first national-level assessment of exposure to ionizing radiation and antineoplastic agents in Canadian veterinary settings. These hazards may pose considerable health risks. Exposures appeared to be low, however our estimates should be validated with comprehensive exposure monitoring and examination of determinants across practice areas, occupations, and tasks.

Fertilizer use and self-reported respiratory and dermal symptoms among tree planters.

In British Columbia, some tree planting operations require workers to fertilize planted seedlings with polymer-coated nitrogen, phosphorus, and potassium (NPK) fertilizers. This study examined respiratory and dermal health associated with fertilizer exposure among tree planters. We interviewed 223 tree planters using an adapted version of the American Thoracic Society questionnaire supplemented with questions on dermal health. Subjects were grouped by categories of increasing duration of exposure, with workers who had not worked with fertilizer as a reference group. The relationship between exposure and reported work-related symptoms was analyzed using logistic regression, adjusting for age, cumulative tobacco cigarettes smoked, marijuana smoking status, sex, and exposure to abrasive spruce needles. An elevated odds ratio was seen for work-related cough, phlegm, nasal symptoms, nosebleed, and skin rash in the highest exposure group (>37 days of fertilizer use in the past 2 years) but was significant only for phlegm (odds ratio = 3.59, 95% confidence interval = 1.10-11.70). Trends of increasing odds ratios with increasing exposure were seen for cough, phlegm, nasal symptoms, and skin rash. The results suggest a weak association between respiratory and dermal irritation and work with fertilizer. Results highlight the need for further exposure monitoring within the tree planting industry, and larger studies to investigate the relationship between work with fertilizer and respiratory and dermal health symptoms. [Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a PDF file containing a respiratory and dermal health questionnaire.].

Exposure to pesticides and metal contaminants of fertilizer among tree planters.

In British Columbia, Canada, harvested forests are manually replanted by seasonal workers. The work is known to be physically demanding and ergonomically difficult, and recently, there have been concerns over chemical exposures due to pesticide residues on seedlings, fertilizers (often applied alongside seedlings), and potential metal contamination of these fertilizers. This study aimed to characterize metal and pesticide exposure among a sample of British Columbia tree planters. Between May 2006 and April 2007, exposure measurements were taken from 54 tree planters at five geographically disperse worksites throughout British Columbia. Four worksites were using fertilizer and one was not. Metal concentrations were measured by inductively coupled plasma mass spectrometry on post-shift hand wipes, full-shift personal air sample, bulk soil, seedling root balls, and fertilizer samples. Pesticides were measured on post-shift hand wipes and on bulk seedling samples. Seedling nursery pesticide application records were used to focus pesticide analyses on pesticides known to have been applied to the seedlings used at the study sites. Carbamate pesticides were analyzed by high-performance liquid chromatography/mass spectroscopy and all other pesticides by gas chromatography mass spectrometry. No evidence was found that tree planters who worked with fertilizer were at an elevated risk of exposure to arsenic, lead, cadmium, chromium, and nickel relative to tree planters who did not. Pesticide residues were found on seedlings taken from work sites early in the tree planting season in April 2007. At these worksites, the fungicides chlorothalonil and iprodione were found on the skin of workers at low levels (range 0.37-106.3 ng cm(-2) and 0.48-15.9 ng cm(-2), respectively), providing evidence for exposure potential. Very poor hygiene conditions were observed at all tree planting work sites. Hand washing facilities were not available at work sites and only 5.6% of subjects reported hand washing during the work day, including prior to eating or smoking. Gloves were worn by all subjects but no personal protective equipment programs existed to train workers in the correct use or selection of gloves, and consequentially, many glove choices were inappropriate. The lack of hand washing facilities combined with incorrect glove use could increase the duration of dermal exposure and increase the risk of hand-to-mouth ingestion exposure.