William E. Longo

Manganese Exposures During Shielded Metal Arc Welding (SMAW) in an Enclosed Space

The work reported here evaluates the effectiveness of various rates of dilution ventilation in controlling welder exposures to manganese in shielded metal arc welding (SMAW) fume when working in enclosed or restricted spaces. Personal and area monitoring using total and respirable sampling techniques, along with multiple analytical techniques, was conducted during the welding operations. With 2000 cubic feet per minute (CFM) (56.63 m 3 /min) dilution ventilation, personal breathing zone concentrations for the welder using 1/8″ (3.18 mm) E6010 and E7018 mild steel electrodes were within 75% of the existing threshold limit value (TLV® of 0.2 mg/m 3 for total manganese and were five times greater than the 2001–2003 proposed respirable manganese TLV of 0.03 mg/m 3 . Manganese concentrations using high manganese content electrodes were five times greater than those for E6010 and E7018 electrodes. Area samples upstream and downstream of the welder using E6010 and E7018 electrodes exceeded 0.2 mg/m3 manganese. Concentrations inside and outside the welding helmet do not indicate diversion of welding fume by the welding helmet from the welders breathing zone. There was close agreement between respirable manganese and total manganese fume concentrations. Total fume concentrations measured by gravimetric analysis of matched-weight, mixed cellulose ester filters were comparable to those measured via preweighed PVC filter media. This study indicates that 2000 CFM general dilution ventilation per 29 CFR 1910.252 (c)(2) may not be a sufficient means of controlling respirable manganese exposures for either welders or their helpers in restricted or enclosed spaces. In the absence of site-specific monitoring data indicating otherwise, it is prudent to employ respiratory protection or source capture ventilation for SMAW with E6010, E7018, and high manganese content electrodes rather than depending solely on 2000 CFM general dilution ventilation in enclosed spaces.

Mineral Fiber Content of Lung Tissue in Patients with Environmental Exposures: Household Contacts vs. Building Occupants

Analysis of tissue mineral fiber content in patients with environmental exposures has seldom been reported in the past. Our studies of six household contacts of asbestos workers indicate that these individuals often have pulmonary asbestos concentrations similar to some occupationally exposed individuals. In contrast, our studies of four occupants of buildings with asbestos-containing materials indicate that these individuals often have pulmonary asbestos burdens indistinguishable from the general nonoccupationally exposed population. However, one such building occupant exposed for many years and who later developed pleural mesothelioma was studied in detail, and it was concluded that her exposure as a teachers aide in a school building containing acoustical plaster was the likely cause of her mesothelioma.

Fiber release during the removal of asbestos-containing gaskets: a work practice simulation.

Work practice studies were conducted involving the removal of asbestos-containing sheet gaskets from steam flanges. These studies were performed to determine potential exposure levels to individuals who have worked with these types of materials in the past and may still work with these products today. The work practices were conducted inside an exposure characterization laboratory (ECL) and were performed by scraping and wire brushing, chrysotile-containing (65% to 85%) sheet gaskets from a number of used steam flanges. Airborne asbestos levels were measured by phase contrast microscopy (PCM) and transmission electron microscopy (TEM) for the personnel and area air samples collected during the study. These workplace simulations showed substantial asbestos fiber release using scraping, hand wire brushing, and power wire brushing techniques during the gasket removal process. The range of concentration was 2.1 to 31.0 fibers/cc greater than 5 micrometers when measured by PCM. These results contrasted with the few reported results in the published literature where lower airborne asbestos levels were reported. In these studies the airborne asbestos fiber levels measured in many of the samples exceeded all current and historical Occupational Safety and Health Administration (OSHA) excursion limits (15-30 minutes) and some previous permissible exposure limits (PEL) based on eight-hour time-weighted average (TWA) standards. Also, individuals who performed this type of work in the past may have had exposures higher than previously suspected. The results demonstrated that employees who remove dry asbestos-containing gaskets with no localized ventilation should wear a full face supplied air respirator with a HEPA escape canister and the work area should be designated a regulated area.

Zonolite Attic Insulation Exposure Studies

Abstract Several studies were designed and conducted to evaluate amphibole asbestos exposures in homes containing Zonolite (expanded vermiculite) attic insulation (ZAI). A range of tasks selected for evaluation included cleaning, working around, moving, and removal of ZAI in attics and living spaces. The fieldwork for these studies was conducted at two homes in Spokane, WA and one home in Silver Spring, MD. Personal and area air samples were collected and analyzed as part of the exposure studies. Surface dust samples and bulk samples were also collected and analyzed. The results demonstrated that airborne concentrations of amphibole asbestos were not elevated if the material is undisturbed. The results also demonstrated that cleaning, remodeling, and other activities did produce significant concentrations of airborne amphibole asbestos when the ZAI was disturbed.

Baseline Studies of Asbestos Exposure During Operations and Maintenance Activities

Abstract Eight simulations of installation, repair, remodeling, and maintenance tasks in buildings with asbestos-containing material (ACM) were conducted to investigate worker exposure to airborne asbestos. Since the tasks were performed using typical custodial and maintenance procedures without regard to the presence of ACM, the results contribute to establishing exposure baselines for custodial and maintenance workers. These baselines can also be used to judge the effectiveness of special operations and maintenance programs designed to minimize asbestos exposure in buildings which contain asbestos materials. Six different types of tasks (moving an office wall, cleaning a storage area, replacing ceiling tile, repairing/installing electrical fixtures, repairing plaster, and removing carpet) and two types of ACM (fireproofing and acoustical plaster) were included in the eight simulations. Exposure was measured by monitoring levels of airborne asbestos before, during, and after the task (and for two simulat...

Emission of Diacetyl (2,3 butanedione) from Natural Butter, Microwave Popcorn Butter Flavor Powder, Paste, and Liquid Products

Abstract Diacetyl (2,3 butanedione), a butter-flavored diketone, has been linked to a severe lung disease, bronchiolitis obliterans. We tested a total of three natural butters and artificial microwave popcorn butter flavorings (three powders, two pastes, and one liquid) for bulk diacetyl concentration and diacetyl emissions when heated. Pastes and liquid butter flavors contained the highest amount (6% to 10.6%) while natural butter possessed up to 7500 times less diacetyl. All artificial butter flavors studied emitted diacetyl. Dry powders emitted up to 1.62 ppm diacetyl; wetted powders up to 54.7 ppm diacetyl; and pastes emitted up to 34.9 ppm diacetyl. The liquid butter flavor emitted up to 17.2 ppm diacetyl. Microwave popcorn flavoring mixtures emitted up to 11.4 ppm diacetyl. At least 93% of the dry powder particles were inhalable. These studies show that microwave butter flavoring products generate concentrations of diacetyl in the air great enough to endanger those exposed.

Exposure to fluoropolymers and VOCs during spray sealant product use.

Fluoropolymer based tile and fabric spray sealants were evaluated for the release of airborne fluoropolymer constituents and volatile organic compounds (VOCs) during typical product use scenarios in a simulated bathroom and a simulated recreational vehicle. Fluoride was quantified after oxygen bomb digestion of airborne spray collected from personal, area, and surface samples. VOCs were quantified by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization spectrometry (GC/FID). Tile grout sealant contained approximately 1% acrylic fluoropolymer resin and 90% VOCs not including propellants. VOCs were short- and medium- chain methylated isoparaffinic hydrocarbons. When horizontally spraying a bathroom shower floor, grout spray sealant released a non-detectable amount of fluoride (<0.8 µg/m3) and 400 – 1400 mg/m3 total VOCs. When vertically spraying a shower wall, up to 2.0 µg/m3 of fluoride and from 1000 to 2300 mg/m3 total VOCs were detected. Fabric spray sealant contained 1% acrylic fluoropolymer resin and approximately 90% VOCs including perchloroethylene (PERC). Fabric spray released from 0.5 to 2.3 µg/m3 fluoride inside a recreational vehicle in the absence of crosswinds and less than 0.5 µg/m3 fluoride in the presence of a 10 mph crosswind. VOC release measured 240 - 938 mg/m3 without crosswinds and 161 - 522 mg/m3 with crosswinds. These studies show that fluoropolymer constituents from fluorinated spray sealants were near non-detectable levels in the breathing zone in nearly all samples while VOCs were measured at elevated levels (>400 mg/m3). The toxicological consequences of elevated VOCs during sealant spraying and the effects of certain fluoropolymer constituents are discussed.

Egilman’s assessment regarding exposures of auto mechanics to amphiboles is correct

Dear Dr. Gardner: We are responding to Dr. Paustenbach’s 2,514 word response almost entirely devoted to one sentence of Dr. Egilman’s original letter: “Victor/Dana used crocidolite in gaskets until at least 1963, Borg Warner used crocidolite in transmission friction plates, Ford hygienists were aware of the use of amosite in brakes, Maremont used crocidolite during the Canadian asbestos strike, and Borg Warner admitted that it used crocidolite in brakes in one set of sworn interrogatories, and denied this in another.” The regular readers of this publication may wonder why so much ink is being spilled over what may seem to be a trivial issue: whether or not brake workers are exposed to amphibole (amosite, crocidolite or tremolite) asbestoscontaining products when they repair or replace automobile parts including brake pads, clutches, gaskets, transmission bands, and mufflers. Every year hundreds of automobile repair workers develop mesothelioma and some of them sue automobile parts manufacturers/sellers for compensation (Lemen, 2004). In fact, hundreds of millions (perhaps) billions of dollars are at stake. In asbestos litigation generally, and in automobile cases in particular, many companies have concocted a “fiber type” defense (Welch, 2007; Egilman et al., 2011). While there are variations, the central feature of this defense is a claim that whichever fiber type was used in a particular company’s products has not been shown to cause mesothelioma. It is undisputed, outside courtrooms, that all fiber types cause lung cancer. Since chrysotile constituted 95% of the fiber used in the US, companies have developed a second line of defense: according to them tremolite found in chrysotile rather than the chrysotile itself is the major cause of mesothelioma in those exposed to chrysotile. Finally, they argue that although chrysotile itself can cause mesothelioma, this only occurs with massive exposure while tremolite and other amphiboles are far more potent. This argument is based on a misinterpretation of the Quebec Asbestos Mining Association studies and has been debunked (Egilman et al., 2003). The “dispute,” which is designed to manufacture doubt over the relative toxicity of different fiber types, did not arise until regulation and litigation commenced in the late 1960s. The tremolite theory was first published in 1995 (McDonald and McDonald, 1995). As a result, asbestos product companies have poured more than fifty million dollars to fund “research” that will show that their products do not contain amphiboles (Egilman et al., 2011). This explains the vehemence and surliness of the current exchange. This is not a dispute over science; it is a dispute that sounds like science. The actual subject matter is the compensation of injured workers, relatives and bystanders which has taken the form of a scientific dispute.