Dean R. Lillquist

Machining Performance and Health Effects of Cutting Fluid Application in Drilling of A390.0 Cast Aluminum Alloy

Environmental issues in machining have led to a push to curtail the use of cutting fluids. However, cutting fluid effects on part quality, process planning, and operator exposure to aerosols need to be first studied. The effects of cutting fluid application on hole accuracy and mist generation have been studied for blind-hole drilling of A390.0 aluminum alloy. Different cutting fluid types and application modes were tested under varying conditions of cutting speed, feed, and hole depth. The cooling and chip-transporting ability of cutting fluids was found to have the maximum effect on dimensional accuracy. Dry cutting yielded holes with the least accuracy, while mist lubrication was found to give superior dimensional accuracy to dry cutting but had the worst aerosol concentration. Flooding with synthetic cutting fluid gave the best overall results.

Fatal injuries in the United States construction industry involving cranes 1984-1994.

There is little published information concerning the epidemiology of injuries in the construction industry involving cranes other than for electrical injury from power line contact. For the 11-year period of 1984 through 1994, the US Occupational Safety and Health Administration (OSHA) investigated 502 deaths in 479 incidents involving cranes in the construction industry. Electrocution was the largest category, with 198 deaths (39%) reported. Other major categories were assembly/dismantling (58 deaths, 12%), boom buckling (41 deaths, 8%), crane upset/overturn (37 deaths, 7%), and rigging failure (36 deaths, 7%). The majority of the deaths during assembly/dismantling involved removal of the boom pins from lattice boom cranes. Only 34% of the construction firms employing the fatally injured workers had ever been inspected by OSHA. OSHA cited the employer for safety violations in 436 deaths (83%). Additional worker training, increased OSHA inspections, and crane inspection programs could prevent many crane-related deaths.

Assessment of Occupational Methyl Tertiary Butyl Ether Vapor Exposures to Petroleum Refinery and Transport Loading Rack Facility Employees

Abstract The use of oxygenated gasoline is required for metropolitan areas which exceed the carbon monoxide nonattainment standard as specified by the Clean Air Act Amendments of 1990. Many petroleum refineries blend methyl tertiary butyl ether (MTBE) with gasoline to make oxygenated fuel, which burns cleaner and reduces carbon monoxide emissions from motor vehicle exhaust. MTBE has a low acute toxicity ranking and is only mildly irritating to the eyes and skin. Excessive acute vapor inhalation causes depression of the central nervous system. Limited animal data indicate that MTBE may increase the risk of cancer, although this has not been adequately addressed. This assessment was conducted to monitor airborne MTBE occupational exposure to petroleum refinery and transport loading rack facility employees at one location. The 47 time-weighted average (TWA) and short-term exposure limit (STEL) personal air samples collected did not exceed the American Industrial Hygiene Association workplace environmental ex...

A Comparison of Indoor/Outdoor PM10 Concentrations Measured at Three Hospitals and a Centrally Located Monitor in Utah

Abstract This research measured daily 24-hour PM10 concentrations at various locations in Salt Lake City, Utah, from November 1994 to May 1995. Between four and six indoor locations were sampled at each of three hospitals. Indoor data were compared with outdoor roof data from each respective hospital and with the citys central monitoring location. The study goals were to: (1) evaluate variation of PM10 concentrations at four different outdoor sampling locations across the Salt Lake Valley; (2) determine if a centrally located monitor can predict PM10 concentrations across the valley; (3) compare indoor/outdoor roof concentrations at three hospitals to determine if an outdoor roof sampler can be used to predict indoor concentrations; (4) evaluate variation in PM10 concentrations inside hospitals to see if a single indoor sampler can estimate exposure for an entire hospital; and (5) determine if a centrally located monitor can predict indoor concentrations in the three hospitals. Results from outdoor sampl...

Comparison of N95 Disposable Filtering Facepiece Fits Using Bitrex Qualitative and TSI Portacount® Quantitative Fit Testing

Abstract As a means of evaluating the use of denatonium benzoate (bitrex) as a qualitative fit test agent with filtering facepiece respirators, the bitrex qualitative and TSI Protacount® quantitative fit-test methods were compared using N95 filtering facepieces. Seventy-nine paired tests (trial) were performed. Detection of bitrex during a qualitative fit test or measurement of a fit factor of <100 during a quantitative fit test constituted a failure. Qualitative and quantitative methods were performed using identical test protocols. Data were analyzed using pass/fail criteria, and matched-pair analysis methods were applied. The results of this study indicate that the use of bitrex during qualitative fit testing of N95 disposable filtering facepieces results in an increase in failure and/or rejection in cases where a TSI Portacount (plus N95 companion accessory) quantitatively establishes an acceptable fit.

The Effect of Thermal Loading on Laboratory Fume Hood Performance

A modified version of the ANSI/ASHRAE 110-1995 Method of Testing Performance of Laboratory Fume Hoods was used to evaluate the relationship between thermal loading in a laboratory fume hood and subsequent tracer gas leakage. Three types of laboratory burners were used, alone and in combination, to thermally challenge the hood. Heat output from burners was measured in BTU/hr, which was based on the fuel heat capacity and flow rate. Hood leakage was measured between 2824 and 69,342 BTU/hr. Sulfur hexafluoride (SF6) was released at 23.5 LPM for each level of thermal loading. Duct temperature was also measured during the heating process. Results indicate a linear relationship for both BTU/hr vs. hood leakage and duct temperature vs. hood leakage. Under these test conditions, each increase of 10,000 BTU/hr resulted in an additional 4 ppm SF6 in the manikins breathing zone (r2 = 0.68). An additional 3.1 ppm SF6 was measured for every 25 degrees F increase in duct temperature (r2 = 0.60). Both BTU/hr and duct temperature models showed p < 0.001. For these tests, BTU/hr was a better predictor of hood leakage than duct temperature. The results of this study indicate that heat output may compromise fume hood performance. This finding is consistent with those of previous studies.

A Comparison of Environmental Sample Methods for Estimating Soil Lead at Trap Shooting Ranges: The Effects of Pellet and Nonpellet Lead

Abstract Lead contamination of soil is a potential problem at trap shooting ranges. Established soil sampling methods currently used may not accurately estimate the average soil lead concentration or the contribution of pelletized lead. A primary concern is whether or not a solid lead pellet finds its way into the representative sample analyzed by the laboratory. This study was conducted to quantify the distribution of pellet and nonpellet soil lead at a trap shooting range and to compare two soil sample preparation methods. The test site consisted of a trap range that has been in use for 40 years with average soil pH of 6.4. Sixty-six composite soil samples were taken at 5-m intervals along a traverse of one trap house. All samples were screened to remove large rocks and plant material, then split. One split, representing current U.S. Department of Housing and Urban Development (HUD) soil sampling methods, was sent directly to a laboratory for lead analysis. The other split was screened to separate lead ...

The Effects of Temperature and Pressure on Airborne Exposure Concentrations When Performing Compliance Evaluations Using ACGIH TLVs and OSHA PELs

Occupational hygienists perform air sampling to characterize airborne contaminant emissions, assess occupational exposures, and establish allowable workplace airborne exposure concentrations. To perform these air sampling applications, occupational hygienists often compare an airborne exposure concentration to a corresponding American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) or an Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL). To perform such comparisons, one must understand the physiological assumptions used to establish these occupational exposure limits, the relationship between a workplace airborne exposure concentration and its associated TLV or PEL, and the effect of temperature and pressure on the performance of an accurate compliance evaluation. This article illustrates the correct procedure for performing compliance evaluations using airborne exposure concentrations expressed in both parts per million and milligrams per cubic meter. In so doing, a brief discussion is given on the physiological assumptions used to establish TLVs and PELs. It is further shown how an accurate compliance evaluation is fundamentally based on comparison of a measured work site exposure dose (derived from the sampling site exposure concentration estimate) to an estimated acceptable exposure dose (derived from the occupational exposure limit concentration). In addition, this article correctly illustrates the effect that atmospheric temperature and pressure have on airborne exposure concentrations and the eventual performance of a compliance evaluation. This article also reveals that under fairly moderate conditions of temperature and pressure, 30 degrees C and 670 torr, a misunderstanding of how varying atmospheric conditions affect concentration values can lead to a 15 percent error in assessing compliance.

Exposure at Home to Airborne Concentrations of Nitrogen Mustard during Topical Application for the Treatment of Mycosis fungoides: A Case Study

Background: Although effective at treating mycosis fungoides (MF), nitrogen mustard (HN2) creates potential exposure risks to those who administer it, including health care workers and family members. Objective: The main objective was to examine the potential for nontarget individuals to be exposed to HN2 vapors during and shortly after treatment with HN2 in a home environment. Methods: Air concentrations of HN2 were measured during the topical treatment of MF in a patients home. Results: The results demonstrate that eye and mucous membrane irritation may occur at HN2 levels commonly encountered during the treatment of MF in the home, hospital or health clinic. Because no exposure thresholds have been developed for HN2, the exposure thresholds of a surrogate chemical (sulfur mustard) were used. Conclusions: The study findings show that eye and mucous membrane irritation may occur at HN2 levels below the exposure thresholds of the surrogate chemical. Recommendations for controlling exposures to HN2 in the home are given.

Effects of Building Ventilation Types and Human Activity Patterns on Indoor PM10 Levels

Abstract Indoor and ambient PM10 levels at two Salt Lake hospitals were examined during the months of January through May 1995. In addition to the PM10 data, the level of human activity was estimated at each of the six indoor sampler sites at each hospital. At each hospital two different air filtration environments were sampled. At hospital A, bag filtration (BF) and high efficiency particulate air (HEPA) systems were sampled, and at hospital C, low efficiency (LE) and BF were sampled. The average ambient PM10 levels at each hospital were significantly different (p < 0.05). At both hospitals the average indoor PM10 for each air filtration system was compared with the ambient PM10 level. In all but one case the indoor PM10 was significantly less than the ambient PM10 (hospital A = 18.7 μg/m3/24 h and hospital C = 26 μg/m3/24 h, p < 0.05). Within an air filtration system some sampler sites had significantly higher average PM10 than did the other sampler sites. The effectiveness of BF versus HEPA and LE vers...