Applied occupational and environmental hygiene最新文献

Current occupational exposures to chemical agents were assessed as part of an epidemiological study pertaining to the cancer and mortality patterns of Ontario construction workers. The task-based exposure assessment involved members from nine construction trade unions. Air samples were taken using personal sampling pumps and collection media. A DustTrak direct-reading particulate monitor was also employed. Exposure assessments included measurements of airborne respirable, inhalable, total, and silica dust; solvents; metals; asbestos; diesel exhaust and man-made mineral fibers (MMMF). In total, 396 single- or multi-component (filter/tube), 798 direct-reading, and 71 bulk samples were collected. The results showed that Ontario construction workers are exposed to potentially hazardous levels of chemical agents. The findings are similar to those reported by other researchers, except for silica exposure. In our study, silica exposure is much lower than reported elsewhere. The difficulty associated with assessing construction workers' exposures is highlighted.

The purpose of this review is to organize and evaluate the epidemiologic evidence regarding the potential carcinogenicity of metalworking fluids. Published literature was initially examined to identify the key contributions, with a strong emphasis on the series of studies by Eisen et al. A key challenge to addressing the issue is the diversity of metalworking fluids, additives, and by-products produced in use, along with the notable changes in the composition and use of such agents over time. Although several smaller cohort studies provided useful data on this issue through the 1980s, the Eisen et al. studies offer unique information given the size of the cohort, sophistication in exposure assessment, and detailed analysis of cancer mortality risks within the cohort as a function of estimated exposure. The most notable associations, based on precision, magnitude, and evidence for increasing risk with increasing exposure are those between straight metalworking fluids and both rectal and laryngeal cancer, as well as soluble metalworking fluids and laryngeal cancer. Further progress will require additional studies of the scale of Eisen et al.'s as well as a more systematic approach to integrating information from toxicology and industrial hygiene into the interpretation of the epidemiologic literature.

Petroleum base oils (petroleum mineral oils) are manufactured from crude oils by vacuum distillation to produce several distillates and a residual oil that are then further refined. Aromatics including alkylated polycyclic aromatic compounds (PAC) are undesirable constituents of base oils because they are deleterious to product performance and are potentially carcinogenic. In modern base oil refining, aromatics are reduced by solvent extraction, catalytic hydrotreating, or hydrocracking. Chronic exposure to poorly refined base oils has the potential to cause skin cancer. A chronic mouse dermal bioassay has been the standard test for estimating carcinogenic potential of mineral oils. The level of alkylated 3-7-ring PAC in raw streams from the vacuum tower must be greatly reduced to render the base oil noncarcinogenic. The processes that can reduce PAC levels are known, but the operating conditions for the processing units (e.g., temperature, pressure, catalyst type, residence time in the unit, unit engineering design, etc.) needed to achieve adequate PAC reduction are refinery specific. Chronic dermal bioassays provide information about whether conditions applied can make a noncarcinogenic oil, but cannot be used to monitor current production for quality control or for conducting research or developing new processes since this test takes at least 78 weeks to conduct. Three short-term, non-animal assays all involving extraction of oil with dimethylsulfoxide (DMSO) have been validated for predicting potential carcinogenic activity of petroleum base oils: a modified Ames assay of a DMSO extract, a gravimetric assay (IP 346) for wt. percent of oil extracted into DMSO, and a GC-FID assay measuring 3-7-ring PAC content in a DMSO extract of oil, expressed as percent of the oil. Extraction with DMSO concentrates PAC in a manner that mimics the extraction method used in the solvent refining of noncarcinogenic oils. The three assays are described, data demonstrating the validation of the assays are shown, and test results of currently manufactured base oils are summarized to illustrate the general lack of cancer hazard for the base oils now being manufactured.

This article is based upon my own experiences with metalworking fluids and the adverse health effects and medical conditions associated with exposure to metalworking fluids. I have researched and witnessed the benefits that can be achieved when metalworking fluids are properly maintained and managed. My experiences have provided insight into how a shop operates, including comprehension of the equipment used, processes, mist generating points, engineering controls currently being adopted, and procedures that are used to maintain metalworking fluids. I have been able to share my personal experiences with the country's leading experts in the field of metalworking fluids. I have presented my insights on the topic in Washington, D.C., to the Standard Advisory Committee of OSHA, as well as at many other conferences nationwide. I have provided awareness training for a number of union and nonunion workers. Being a part of developing successful metal removal fluid programs, I realize the importance of transferring and sharing information. Many times an organization is not fully aware of certain conditions and how to combat them. My mission and intent is to properly educate those who are exposed to the harm that metalworking fluids can invoke and to inform those involved of the possible methods of reducing long- and short-term risk. One thing that must be kept in mind is the way we view these fluids. Many shops categorize the fluids as a type of "operating expense" when they should actually be seen as a sort of investment. Just as performing a scheduled maintenance on a machine promises the best possible longevity of that machine, the upkeep of metalworking fluid also provides longer "tool life." Monitoring and maintaining the fluids also provides for more effective and efficient productivity. If we fail to consider that proper management of the fluids can cut cost dramatically, then we will miss out on the financial impact they can have on a company. Try looking at the fluids as a liquid tool. Doing so I believe will bring a better understanding of the value of a successful metalworking fluids program. With this new understanding, it can be seen just who must play a role in the management of metalworking fluids. The employees who deal with the daily tasks involving the coolant play a major part. They are on the floor where these metalworking fluids are being used. In many shops, it is assumed that the environmental health & safety departments are responsible for standard operating procedures and management of fluids. The EH&S department should only be responsible for the protection from exposure and the transfer of information regarding policy and procedure to their employees. Not all shops have the resources required to develop and implement the proper standard operating procedure. Therefore, we must understand that what is feasible for one may not be for another. Companies that lack the sufficient resources should not be neglected. It is crucial t

On October 15, 2002, the United Kingdom (UK) Health and Safety Executive (HSE) launched new guidance for the engineering industry, aimed at reducing health risks from metalworking fluids (MWFs). This guidance was the culmination of many years of work on this subject. In the early 1990s, the UK occupational exposure standards (OES) for oil mist were 5 mg/m(-3) 8-hour time-weighted average (TWA), and 10 mg/m(-3) short-term exposure limit (STEL). This was only applicable to highly refined mineral oil mists and there was no exposure limit for water-mix MWFs (emulsions, semi-synthetics, and synthetics). HSE therefore undertook to review the existing exposure limit for neat mineral oil mists (neat oils are fluids that contain highly refined mineral oils and additives, and are used neat without mixing with water) and consider developing one for water-mix MWFs. This led to the development of new air-sampling methods, a comprehensive survey, and the development of new good practice guidance in the place of statutory exposure limits. This new good practice guidance has been endorsed and launched with the help of relevant industry supplier, employer, and employee associations. The guidance builds on the philosophy of tackling health risks as a holistic approach; for example, not just tackling mist control through the use of ventilation, but also fluid selection, fluid delivery, and fluid management (fluid management means to effectively manage all aspects of the fluid, from storage and stock preparation to sump cleaning and fluid disposal, etc.). Tools, such as laminated task sheets, are provided to make it user friendly. It also demonstrates the business benefits from this approach, that managing your MWFs effectively can reduce the incidence of ill health, reduce fluid and disposal costs, increase tool life, and improve machining performance.

Effective mist collection is important, but it is not the only determinant of mist concentration in plant air. Oil-based metalworking fluids such as straight and soluble oils contain semivolatile hydrocarbons. When these fluids form a mist, their semivolatile components partition between the vapor and mist phases depending on the makeup of the mist and on local conditions. This article addresses the relationship between the concentrations of semivolatile hydrocarbons in the vapor and mist phases using theory for partitioning developed in the field of atmospheric chemistry. Mist can be removed effectively in a collector that uses a HEPA filter as its final collection stage. Acceptable HEPA lifetime requires effective upstream stages that reduce mist loading to the HEPA; furthermore, acceptable HEPA performance requires that it be installed and maintained properly. Collectors designed to remove mist do not remove vapor, and as collector exhaust mixes into cooler plant air that already contains some mist, vapor from the collector can repartition to increase the mist concentration in the plant. Assessing the effect of vapor-to-mist repartitioning is complicated; however, repartitioning may be important for many of the compounds contained in oil-based metalworking fluids. Conditions that minimize vapor-to-mist repartitioning, such as ventilating the plant with clean outdoor air, increasing plant temperature, or controlling the release of vapor, may also be expensive, uncomfortable to plant occupants, or impractical from an engineering standpoint. As a result, very low mist concentrations in plant air may be difficult to attain.

The measurement of oil mist derived from metalworking fluids formulated with light mineral oils can be highly inaccurate when using traditional filter sampling. This is due to evaporation of oil from the filter. In this work the practicability of an alternative approach measuring total oil mist and vapor was investigated. Combinations of inhalable particle samplers with backup sorbent vapor traps and standard vapor sampling on pumped and diffusive sorbent tubes were evaluated with gravimetric, infrared spectroscopic, and gas chromatographic analytical methods against the performance requirements of European Standard EN 482. An artificial aerosol was used to compare the methods against a reference method of filter sampler in series with three impingers. Multi-orifice samplers were used with standard 8-mm diameter charcoal tubes at 2 L/min without any signs of channelling or significant breakthrough, as were conical inhalable samplers with XAD-2 tubes at 1 L/min. Most combinations of samplers had a bias of less than 3 percent, but solitary pumped charcoal tubes underestimated total oil by 13 percent. Diffusive sampling was affected by impaction of mist particles and condensation of oil vapor. Gravimetric analysis of filters revealed significant potential sample loss during storage, with 4 percent being lost after one day when stored at room temperature and 2 percent when refrigerated. Samples left overnight in the balance room to equilibrate lost 24 percent. Infrared spectroscopy gave more precise results for vapor than gas chromatography (p = 0.002). Gas chromatography was less susceptible to bias from contaminating solvent vapors than infrared spectroscopy, but was still vulnerable to petroleum distillates. Under the specific test conditions (one oil type and mist particle size), all combinations of methods examined complied with the requirements of European Standard EN 484. Total airborne oil can be measured accurately; however, care must be taken to avoid contamination by hydrocarbon solvent vapors during sampling.

The 1998 National Institute for Occupational Safety and Health (NIOSH) criteria document for metalworking fluids (MWF) is the most recent authoritative review of mortality studies of workers with these exposures. NIOSH concluded that substantial evidence exists for increased risk of cancer at several sites (larynx, rectum, pancreas, skin, scrotum, and bladder) among workers exposed to MWF before the mid-1970s, and that evidence is equivocal for cancer at several other sites, including stomach, esophagus, lung, prostate, brain, colon, and hematopoietic system. The UAW believes that systematic analysis of that body of data makes a much stronger case for stomach cancer related to MWF exposure. Since the Criteria document, the mortality experience of three of the cohorts reviewed has been either updated or reanalyzed. These updates strengthen the evidence for increased mortality from stomach and liver cancer, and non-malignant respiratory disease associated with exposure to water-based metalworking fluids. Additional toxicological data providing clear evidence for carcinogenicity of diethanolamine, a widely used ingredient, also increases the biological plausibility of these findings. Despite changes in composition of MWFs with time, and reduced exposure levels, these data contradict the notion that cancer risks have been eliminated.