Fingerprinting of yeasts at the strain level by differential sensitivity responses to a panel of selected killer toxins.

We used differential sensitivities to a panel of twenty-five cell-free crude killer toxins to fingerprint forty-four Saccharomyces cerevisiae strains of different origin and all taxonomically certified by nDNA-nDNA reassociation. Cluster analysis of numerical data obtained by different growth inhibition areas observed in Petri dishes allowed the complete and reproducible discrimination of all S. cerevisiae strains.

The use of 3M porous polymer extraction discs in assessing protective clothing chemical permeation.

The aim of the study was to assess the use of 3M porous polymer extraction discs (3M Empore sorbent filters) for detection of chemical permeation of protective clothing. Analysis of some commonly used solvents on 3M Empore sorbent filters was performed for methanol, acetone, trichloroethylene (TriCE), and toluene by solvent desorption and gas chromatography. All solvents exhibited >98 percent adsorption on the filters at a spiking level of 1.8 microL for each solvent. Solvent recovery for the system was calculated for each solvent, ranging from 72-94 percent (RSD < or = 4.0%) for all solvents over the spiking range 0.2-1.8 microL. The modified ASTM F739 method was used to determine breakthrough times for five protective glove materials (polyvinyl chloride, natural rubber, polymerized alkene, nitrile, and nitrile butyl rubber) using the model solvents as test chemicals. Breakthrough times for each type of protective glove were determined, and found to range from 36 s to 9 min for acetone, from 142 s to 52 min for methanol, from 18 s to 12 min for TriCE, and from 32 s to 28 min for toluene. The quantitative mass of the solvents on the filters at the time of breakthrough detection ranged from 150-159, 157-166, 570-581, and 371-382 microg/cm2 for acetone, methanol, TriCE, and toluene, respectively. The sorbent filter should find utility in collecting chemical permeation samples through protective gloves in both laboratory and field studies for quantitative analysis.

Respiratory symptoms among crab processing workers in Alaska: epidemiological and environmental assessment.

BACKGROUND: Crab processing workers may develop respiratory symptoms and specific IgE responses, but the risk factors have not been fully described. METHODS: In 1998, 107 workers at a crab processing facility completed a survey both at the beginning and end of the processing season. The surveys included standardized symptom questionnaires, spirometry, and serological testing, as well as measurement of workplace airborne crab allergens and microscopic analysis of aerosolized materials. RESULTS: Over the crab processing season, asthma-like symptoms developed in 26% of study participants and bronchitic symptoms in 19%. Only 9% of those with new asthma-like symptoms were IgE-sensitized to crab at the end of the season. Among the crab processing jobs, butchering and degilling workers had the highest incidence of respiratory symptoms. CONCLUSIONS: Both personal and process-related factors appear to affect the development of respiratory symptoms in crab processing workers. In this study, crab specific IgE was not detected in most of the workers with new symptoms. Published 2001 Wiley-Liss, Inc.

A quantitative study of aromatic amine permeation through protective gloves using amine adsorptive pads.

A quantitative study of aromatic amine permeation through a glove material using Permea-Tec aromatic amine pads, used for the detection of chemical breakthrough of protective clothing, was performed for aniline following the microwave extraction process and gas chromatographic analysis. Aniline exhibited >99% adsorption on the pads at a spiking level of 1.94 mg (1.9 microL). Aniline showed recoveries from 65 to 89% (RSD < or =5.6%) over the range 1.1-1.9 microL (1.12-1.94 mg) of aniline applied to pads. The modified ASTM F739 and direct permeability testing procedures were used to determine breakthrough times for five protective glove materials using aniline as a challenge chemical. Breakthrough times for six protective gloves were determined, ranging from 182 sec to 82 min. The quantitative concentration of aniline on the pads following permeation through the gloves also was determined, ranging from 0.53 to 0.55 mg/cm2 (1.79-1.88 mg/pad).

Determination of alkylamine permeation through protective gloves using aliphatic amine pads.

A quantitative study of alkylamine permeation through a glove material using Permea-Tec aliphatic amine pads, used for the detection of chemical breakthrough of protective clothing, was performed for triethylamine following a microwave-extraction process and gas chromatographic analysis. Triethylamine exhibited > 99% adsorption on the pads at a spiking level of 729 ng (1.0 ml). Triethylamine showed recoveries from 63 to 90% (RSD < or = 5%) over the range 0.2-1.0 ml (146-729 ng) applied to pads. The ASTM F739 standard and direct permeability testing procedures were used to determine breakthrough times for five protective glove materials using triethylamine as a challenge chemical. Breakthrough times for six protective gloves were determined ranging from 40 s to > 4 h. The quantitative concentration of triethylamine on the pads following permeation through the gloves was also determined, ranging from 101 to 103 ng cm-2 (382-386 ng per pad).

Recovery of some common solvents from protective clothing breakthrough indicator pads by microwave-solvent extraction and gas chromatography.

The efficiency of solvent adsorption using Permea-Tec general solvent pads, used for the detection of chemical breakthrough of protective clothing, was determined for methanol, acetone, ethyl methyl ketone, trichloroethylene (TriCE), tetrachloroethylene (TetCE), toluene, m-xylene, and D-limonene. Known volumes of single or mixed solvents were added to pads in the range 0.2-5.0 microliters (0.16-8.13 micrograms). After microwave-solvent extraction (ME) into hexan-1-ol, the samples (0.5-3.0 microliters) of the filtered and extracted solutions were analyzed by gas chromatography. All solvents exhibited > 97% adsorption on the pads at spiking levels of 0.48-0.98 microgram for each solvent. The solvent recovery for the system was calculated for each solvent, with solvents with boiling points below 110 degrees C showing recoveries of > 90%, and with solvents with boiling points above 110 degrees C showing recoveries from 80 to 90%. The recovery precision was good (RSD < or = 4%) for all solvents over the range 1.0-2.5 microliters of applied solvents to pads for ME and 1.0 microliter of extracted solutions for GC analysis.

Ammonia and ethylene oxide permeation through selected protective clothing.

An automated permeation test system was developed to collect permeation data. Three test specimens were evaluated simultaneously versus a challenge gas. The study evaluated chemical protective clothing garment materials for use by emergency response personnel confronted by ammonia or ethylene oxide in the gas phase. A total of 13 encapsulating suit materials and 2 glove materials were tested. Surgical latex material is not recommended for use in handling ammonia or ethylene oxide; other materials offer much greater protection.

Using immersion test data to screen chemical protective clothing.

A test to screen chemical protective materials in order to select potential candidates for further testing has been examined. The method involved determining the weight and volume changes in materials caused by immersion in the challenge chemical. Simple regression analysis showed that relatively short breakthrough times based on weight change and final thickness could be predicted with 90% confidence. Better results were obtained when discriminant analysis was used to classify breakthrough times greater than either 4 or 8 hr as a function of the weight change and final thickness. In 6% or less of the cases, actual breakthrough times were less than 4 or 8 hr when the predicted times were greater than these values. Discriminant analysis also was used to classify permeation rates as less than either 90 or 400 mg/m2-min based on weight change and initial thickness. In this case, actual permeation rates less than these were predicted to be greater in 4% and 7% of the cases, respectively.

Chemical protective clothing breakthrough time: comparison of several test systems.

This study compared chemical permeation data obtained with a photo-ionization detector in both open- and closed-loop test systems. Also, chemical permeation data obtained at two flow rates with an infrared detector in a closed-loop test system were compared. Breakthrough times for acetone-neoprene were obtained using all systems. Results were evaluated and determined to be system dependent.

Chemical protective clothing standard test method development. Part 1. Penetration test method.

A "round-robin" interlaboratory study was conducted to validate the relative precision of the American Society for Testing and Materials (ASTM) F-903 test method for measuring the resistance of protective materials to penetration by liquids. The study utilized seven independent laboratories performing three trials of five protective clothing materials challenged by five widely used commercial liquids. The level of overall agreement for interlaboratory results suggests a relatively high confidence in the precision of the method. Systematic errors, however, may reduce the confidence of this method for certain materials and solvents. Recommendations to eliminate or reduce variability due to systematic errors include reduction of test pressure, use of a support screen, reporting of permeation evidence as a failure, and the use of a fluorescent dye to enhance visibility.

Chemical protective clothing standard test method development: Part II. Degradation test method.

A "round-robin" interlaboratory evaluation of a proposed American Society for Testing and Materials (ASTM) standard test method was conducted for measuring the resistance of chemical protective clothing materials to degradation by liquid chemicals. The objective of this project was to determine the relative precision of the method and, where appropriate, recommend modifications that would improve reliability. In the round-robin format, eight laboratories used the proposed method to test each of five protective clothing materials against five liquid chemicals that are widely used commercially. The resulting data revealed that the proposed test method was not stringent enough to generate acceptable levels of accuracy and precision. Both intra- and interlaboratory standard deviations showed a high degree of variability in changes for the three physical properties evaluated. Changes in the method were identified which, if implemented, should improve accuracy and precision considerably.

Prevention of occupational skin disease through use of chemical protective gloves.

Selection of chemical protective gloves for use against industrial liquids in the controlled workplace is accomplished by risk analysis, in which the appropriate physical and chemical glove properties needed by the worker to perform the job are determined. Candidate protective gloves are then subjected to chemical permeation testing. Three representative case studies illustrate risk analysis and glove selection.

A portable chemical protective clothing test method: application at a chemical plant.

The National Institute for Occupational Safety and Health (NIOSH), in cooperation with Monsanto Chemical Company, conducted an on-site evaluation of chemical protective clothing at Monsanto's Nitro, West Virginia plant. The Monsanto plant manufactures additives for the rubber industry including antioxidants, pre-vulcanization inhibitors, accelerators, etc. This survey evaluated six raw materials that have a potential for skin absorption: aniline, cyclohexylamine, diisopropylamine, tertiary butylamine, morpholine and carbon disulfide. Five generic glove materials were tested against these chemicals: nitrile, neoprene, polyvinylchloride, natural latex and natural rubber. The NIOSH chemical permeation portable test system was used to generate breakthrough time data. The results were compared to permeation data reported in the literature that were obtained by using the ASTM F739-85 test method. The test data demonstrated that aniline has too low a vapor pressure for reliable analysis on the portable direct reading detectors used. The chemical permeation test system, however, provided comparable, reliable permeation data for the other tested chemicals. Monsanto has used this data to better select chemical protection clothing for its intended use.

Penetration of methyl isocyanate through organic vapor and acid gas respirator cartridges.

Methyl isocyanate (MIC) is a volatile, toxic chemical [Threshold Limit Value (TLV) = 0.02 ppm] used to manufacture carbamate pesticides. The principal manufacturer of MIC is Union Carbide, and the site of production is Institute, West Virginia. In light of the December 1984 Bhopal, India disaster and possible safety problems at the Institute facility, NIOSH conducted this research as a basis upon which to recommend protective equipment that might be used in an emergency situation where extremely high MIC concentrations might be encountered. Both protective clothing and respirators were evaluated. In particular, NIOSH studied air-purifying respirators in order to assess their effectiveness against MIC vapor penetration. NIOSH does not recommend any air purifying respirator for MIC because of its high toxicity and lack of warning properties and because no effective end of service life indicator currently is available for MIC. This report addresses only MIC penetration through air-purifying cartridges at challenge concentrations designed to simulate emergency escape conditions. Another report addresses the protective clothing issue. The results presented are for two different manufacturers' organic vapor (OV) and acid gas cartridges. Penetration tests were conducted at three or four MIC challenge concentrations and at three different humidity conditions. In general, breakthrough times (1% of challenge concentration) were very short (less than 20 min). Also, high relative humidity was found to decrease the breakthrough time of MIC.

Methyl isocyanate liquid and vapor permeation through selected respirator diaphragms and chemical protective clothing.

Initially, a study was undertaken to evaluate selected chemical protective clothing suitable for use by emergency response personnel confronted with methyl isocyanate (MIC). Twenty-two chemical protective clothing materials were tested against liquid methyl isocyanate. Chemical permeation breakthrough times for these clothing materials demonstrate that only one of these garments can be considered as a candidate material against liquid MIC. In a subsequent study, three chemical protective clothing materials were evaluated against approximately 800 ppm MIC vapor. Chemical permeation breakthrough times demonstrate that these materials can be considered candidate materials. A final study tested self-contained breathing apparatus (SCBA) diaphragms. Four SCBA diaphragms were tested and all experienced rapid breakthrough when exposed to liquid MIC. Next, three SCBA diaphragms were exposed to approximately 800 ppm MIC vapor. The data demonstrate that the SCBA should be worn inside a total encapsulating suit.

Permeation of chemical protective clothing by three binary solvent mixtures.

An evaluation of glove materials against three different binary chemical mixtures selected from common industrial solvents was conducted. Changes in breakthrough time and permeation rate of the mixture components were evaluated as a function of the mixture composition. An increase in employee risk resulting from early mixture breakthrough time and enhanced mixture permeation rate over that of the pure chemicals was demonstrated. The permeation of a binary mixture through chemical protective clothing could not be predicted by the permeation results of the pure components. It is recommended that chemical protective clothing be tested for its permeation characteristics with the use of the chemical mixtures and conditions that reflect the work site exposure.

New germ tube induction medium for the identification of Candida albicans.

A new germ tube induction medium, composed of three parts Rabbit Coagulase Plasma with EDTA (BBL Microbiology Systems) and two parts Tryp-Soy broth (Scott Laboratories, Inc.), was effective for the presumptive identification of Candida albicans. This medium was safer to use, more accurate, and less expensive than other commercial germ tube induction media.

Site-specific whole glove chemical permeation.

This study explored chemical permeation of latex neoprene gloves by acetone. Twenty-three specific glove sites were monitored to determine the breakthrough time and the challenge liquid concentration at steady-state. In summation, the thinnest parts of the gloves, which are the backs, the palms, and the interstices between the fingers, exhibited the shortest breakthrough times and largest steady-state concentrations. The thickest parts of the gloves, the fingertips, exhibited the longest breakthrough times and least steady-state concentrations. The backs or palms are appropriate specimens to use for chemical permeation testing.

Permeation of eleven protective garment materials by four organic solvents.

The resistance of 11 different protective garment materials to permeation by epichlorohydrin, perchloroethylene, trichloroethylene, and 1,2-dibromoethane were determined. Water was the collection medium in the epichlorohydrin tests with samples taken periodically and analyzed by gas chromatography. Because of the relatively low solubilities of the other three challenge liquids in water, air was used as the collection medium. The concentrations of the permeant vapors in an airstream which passed across the downstream sides of the membranes were determined automatically every 2 min with a flame ionization detector. Butyl rubber offers good protection against epichlorohydrin, with breakthrough occurring after 8 hrs. With the halogenated hydrocarbons, Viton and Vitrile provide protection for at least 12 and 24 hrs, respectively, while PVA showed no breakthrough in 24 hrs with trichloroethylene and dibromoethane. With perchloroethylene, nitrile breakthrough occurred in 5 hrs. The weight and volume changes which occurred when the materials were soaked in each of the challenge liquids were also determined. The log of these changes correlated moderately well with the log of the breakthrough time normalized by the square of the material thickness.