A. Palaszewska, A. Swidwinska-Gajewska, Nofer Institute of Occupational Medicine, Lodz, Poland.
In January 2005, the Nofer Institute of Occupational Medicine (NIOM) started to collect and analyze data about acute releases of hazardous substances as the result of cooperation with the Agency for Toxic Substances and Diseases Registry concerning the hazardous substances emergency events surveillance system implementation in Poland. The initial goal of the study was to estimate the level, severity, and structure of chemicals releases in Poland, together with their potential consequences to public health and environment. The kind of data gathered for the 2-yr period enabled detailed description of temporal and spatial distribution of emergencies connected with hazardous substances releases. Moreover the morbidity and mortality among employees, first-responders, and the general public were also described. As long-term goals, NIOM intends to identify the risk factors and develop and describe strategies and new rescue action procedures, the introduction of which would result in reducing the frequency and severity of injuries occurring during chemical emergencies. The structure of hazardous chemicals releases, subsequent types of injuries, and rescue procedures proposed for each separate substance or group of substances also will be presented.
S. Tarkington, A. Harris, P. Barton, B. Chandler, P. Goad, Center for Toxicology and Environmental Health, LLC, Little Rock, AR.
Shelter-in-place strategies are often recommended by emergency services personnel to protect the general public after a release of volatile hazardous chemicals. These strategies include remaining indoors; breathing through a dampened cloth; sealing cracks in windows and doors using towels, duct tape, or plastic sheeting; and running a shower. Similar recommendations have been made to and used by community members after a release of large quantities of anhydrous ammonia, following the derailment of a tank car or other catastrophic releases. Using one or more of these recommended shelter-in-place strategies has proven to decrease — and sometimes eliminate — injuries during major chemical releases. Although some studies have evaluated the effectiveness of remaining in the home or breathing through a wet cloth, there have been no studies that directly address their usefulness for ammonia or measure the efficacy of turning on a shower to reduce ammonia concentrations. To do this, a chamber was built to simulate sheltering-in-place inside a typical bathroom with the shower on. Ammonia gas at 300 and 1000 ppm was introduced into the chamber to simulate exposure. The effectiveness of breathing through a dampened cloth was evaluated using a CPR manikin placed inside the chamber. Real-time monitoring devices were used to continuously monitor the atmosphere inside the chamber during the studies. After the ammonia concentration peaked and stabilized, the shower was turned on. Operating the shower rapidly reduced the ammonia concentrations over a short period. A typical run resulted in a reduction of the ammonia concentrations of at least 98% from the initial concentration after approximately 27 min, even though ammonia gas was being continuously added to the chamber. These results indicate that using these shelter-in-place strategies can substantially reduce exposure after a catastrophic release of ammonia.
K. Kirollos, G. Mihaylov, T. Tekleab, Microteq, LLC, Virginia Beach, VA.
Post-Sept. 11, there is an increasing and unprecedented terrorist threat to the military and civilian populations. Military personnel and first responders are in great need of a fast, selective, highly sensitive, and easy-to-use system for the detection of chemical warfare agents in the air.
This presentation shows a new and validated system for the detection of chemical agents in air. The system consists mainly of a manifold with a pistol-grip handle holding five detector tubes connected to one push-button electric sampling pump. Within 4 min, the system is capable of selective detection of nerve agents (3x10-6mg/l), mustard agents (0.005mg/l), lewisites (0.002mg/l), cyanogen chloride (0.002mg/l), hydrogen cyanide (0.002mg/l), phosgene (0.002mg/l), and diphosgene (0.002mg/l). The detection limits are significantly below the U.S. Joint Services Operational Requirements. The operation of the system was tested and validated at temperatures ranging from 10oC to 40oC and relative humidities ranging from 10 to 80 RH.
Rigorous testing and validation using representative chemical agents were conducted by the U.S. Army Soldier Biological and Chemical Command at Aberdeen Proving Ground, Md.
The system also includes a manual pump and venturi pump as optional alternatives for the electric pump. The short sampling time and ease of use, together with the favorable testing and validation, make this detection system a viable and useful means of detecting chemical warfare agents in emergencies.
C. Stanion, Duke University & Health System/University of North Carolina, Chapel Hill, NC.
Two million U.S. employees work closely with animals and are at risk of developing animal-induced occupational allergies and asthma. This study examines the cost-effectiveness of respiratory protection to prevent these diseases, compared to respirator use only by those with symptoms. A Markov cohort simulation was used to estimate the development of animal-induced allergies and asthma over six years among 1000 newly animal-exposed employees under both respiratory protection scenarios. Model parameters were based on a review of relevant epidemiology literature. Costs were based on wage data from the Bureau of Labor Statistics, respirator prices from national suppliers, and medical costs gathered from the literature. Incremental cost-effectiveness ratios (costs per prevented case of allergies and costs per prevented case of asthma) were calculated from societal and employer perspectives. From the societal perspective, which includes the costs of medical treatment, using respiratory protection to prevent development of allergies and asthma is estimated to cost an additional $950 per prevented case of allergies or $3300 per prevented case of asthma, compared with using respiratory protection only for those with symptoms. From the employer’s perspective, the incremental cost-effectiveness ratio is estimated at $3500 per prevented case of allergies or $11,000 per prevented case of asthma, assuming that the employer would not directly benefit from reduced medical costs. One-way sensitivity analysis indicated that the model was most sensitive to the probability of disease development among healthy employees wearing respirators. The use of respiratory protection for the prevention of animal-induced occupational allergies and asthma is more cost-effective for society than for employers. Employers may be hesitant to adopt the use of respiratory protection among all animal-exposed employees because they would bear most of the costs, but they may not directly benefit from reduced allergies and asthma among their employees.
P. Grogin, K. Brandt, Los Alamos National Laboratory, Los Alamos, NM.
Suspect/counterfeit items (S/CI) are becoming an increasing concern to business and industry. Undetected S/CI in safety-related or mission-critical applications can cause electrical or mechanical failure that may lead to personnel injury or death. According to a February 2005 article in Business Week, the World Customs Organization estimated that counterfeiting in 2004 was equivalent to $512 billion in lost sales. During the same year, seizure of counterfeit items by U.S. Customs and Border Protection increased by 46%. The Los Alamos National Laboratory (LANL) has taken an active role in addressing the S/CI problem. In addition to a procurement program designed to minimize the purchase of S/CI, LANL has increased work force awareness of S/CI through a variety of media, including live classes, informational fliers, posters, and reference cards. Live training, developed specifically by and for LANL, includes an overview of past and current S/CI issues, LANL’s procurement and S/CI identification processes, and systems for preventing the introduction of S/CI into the workplace. LANL uses photographs and actual examples of both suspect and known counterfeit items to familiarize trainees with the methods of detecting counterfeit materials and equipment in the field. Informational fliers describe and illustrate specific SC/I items that are known to exist within the workplace. These fliers include summaries that describe actual S/CI discoveries and resources to contact if personnel have questions about S/CI at their work sites. In certain courses, instructors provide pocket-sized suspect/counterfeit bolt reference cards to trainees. The Institutional ESH (Environment, Safety, and Health) Training Center displays posters to raise the awareness of new and returning trainees and sends copies of the posters and fliers to other LANL areas upon request. This increased awareness has assisted with the identification of a variety of S/CI found in areas throughout LANL before the items failed and possibly could have caused injury to personnel or damage to property.
G. Tencer, N. Greeson, Duke University, Durham, NC.
Large, modern universities are so complex and diverse that meaningful analysis of work-related injuries and illnesses is extremely difficult. University business can span a wide spectrum of industries, including academic instruction, research, hospitals, clinical practices, clinical laboratories, construction and maintenance, transportation, law enforcement, and infrastructure activities such as housekeeping and foodservice. Analysis of the organizational structure and component function, followed by operational group mapping of work-related injuries and illnesses, can result in much more useful data. At Duke University Health System, an institution with over 32,000 employees, we employed a three-step process. The first step divided the institution into companies in alignment with the institution’s management hierarchy. These companies are independent entities with individual missions and functions. A separate OSHA 300 log is maintained for each. The second step split up the companies into smaller operational units, to delve deeper into areas of concern. For each of these units, we calculated quarterly rates of work-related injuries and illnesses that resulted in days away from the days away/restricted or transfer (DART) rate. Groups with DART rates above a selected threshold were targeted for additional focus and intervention. The final step was to enhance investigation of work-related injuries and illnesses, which yielded a better perspective of causative factors. This in turn led to improved communication with targeted groups. The strategy employed at Duke has resulted in many improvements, such as more reliable benchmarking, both internally and externally. Further, intercompany collaboration at the operational group level has fostered shared solutions for reducing hazards (for example, focusing on slips and falls in wet work environments). The process has enabled a better understanding of causative factors, allowing management to focus on problems within its control. Through this strategy, Duke has reduced work-related injuries and illnesses — a trend that continues.
E. Reed, Liberty Mutual Insurance Co., Englewood, CO; E. Stevenson, Liberty Mutual Insurance Co., Hopkinton, MA.
Environmental health and safety (EHS) professionals usually have strong feelings about the value of safety, typically surrounding thoughts like protecting workers against accidents, avoiding injuries, and providing a healthful workplace. This presentation instead focuses on the financial cost and benefits of our control recommendations, where industrial hygienists (IHs) have more difficulty explaining their value. This presentation uses IH examples and focuses on the barriers between safety performance and business value in order to enhance knowledge and understanding of (1) workplace accident and injury costs, (2) safety and IH as a business expense and investment, (3) safety in support of business values, (4) the linking of safety and business outcomes and the effects of safety to the bottom line, and (5) reasons why EHS professionals need to help senior financial executives understand the process of improving safety. Control recommendations are evaluated based on straightforward financial applications for the net present value of money as applied to the recommendations. The analysis tries to capture all the costs and savings for the proposed controls and can compare alternative safety controls from a business perspective.
V. Turcotte, McGill University/MHV Inc., Montréal, QC, Canada; C. Dion, S. Viau, IRSST, Montréal, QC, Canada; A. Dufresne, McGill University, Montréal, QC, Canada.
In this study, our objective was to develop a protocol to test the efficiency of cleansing solutions in the decontamination of surfaces made of beryllium/copper. The surfaces examined included a beryllium-copper mold used for the extrusion of 100 mL plastic bottles and beryllium/copper thin plates (2 mm). Decontamination was performed by wiping each surface with Ghost Wipes moistened with one of five solutions: (1) Citranox, a 2% acid solution, (2) Alconox, a 1% basic solution, (3) Luminox, a 4% neutral solution, (4) Fantastik, and (5) warm water. Beryllium concentrations on Ghost Wipes were then analyzed by inductively coupled plasma mass spectroscopy (ICP-MS) in the IRSST laboratory according to method IRSST 359. For the first decontamination, when we analyzed wipes used for the five solvents, beryllium concentrations on the mould’s surface ranged from 1.98 to 35.7 µg/100 cm2, with Citronox showing the highest performance for removing beryllium. After this first decontamination, residual concentrations of beryllium were still detectable and varied from 0.09 to 0.80 µg/100 cm2. The second decontamination, with Alconox, Citranox, and Luminox alone, yielded beryllium concentrations of 0.57, 2.44, and 31.1 µg/100 cm2, respectively. Residual beryllium concentrations after this second decontamination were 0.15, 0.22, and 1.60 µg/100 cm2 for Alconox, Citronox, and Luminox, respectively. The decontamination of the plate showed a similar pattern. Of the three solutions used in this project, Citronox was the most efficient cleansing solution and removed the highest concentration of beryllium on the mold’s surface as well as the plate (results not shown). However, it was still possible to extract beryllium after successive decontamination procedures conducted over several weeks. Therefore, our observations suggest that the present experimental conditions do not allow us to reach the decontamination criterion of 0.2 µg/100 cm2.
S. Czerczak, A. Palaszewska, The Nofer Institute of Occupational Medicine, Lodz, Poland.
A regulation of the Minister of Health of Dec. 1, 2004, addresses carcinogenic or mutagenic substances, preparations, agents, or technological processes in the working environment, in accordance with European Union legislation. Containing a registry of over 800 carcinogenic and mutagenic agents, the regulation describes employers’ duties with respect to workers’ exposure to carcinogens. Because employees’ health is a priority, the employer is obliged to monitor both health parameters and the working environment for occurrence of carcinogens as well as their type and potential exposure levels. Moreover, employers have to characterize health risks resulting from occupational exposure to specific chemicals. As health risk assessment is a complex and difficult process, Nofer Institute of Occupational Medicine (NIOM) prepares guidelines for employers and relevant labor safety services containing detailed toxicological profiles and health-risk characteristics for different carcinogens. The chemical (carcinogen) is described in terms of its physicochemical properties, usage, exposure, occurrence, toxicity, carcinogenic, mutagenic, and reprotoxic potential. Both qualitative and quantitative risk assessment of the neoplastic changes development are made for each. Quantitative risk assessment, which has enabled estimation of the potential health risk with reference to the specified exposure levels within specific working conditions, has been made for nearly 100 carcinogenic agents.
L. Butler, University of British Columbia, Vancouver, BC, Canada.
Our objective was to develop a chemical exposure risk prioritization and assessment model for an oil refinery that could be applied to chemical exposures at any of the refinery’s units or to the operators under normal operating conditions. Chemical hazards and exposure characteristics were identified at two of the refinery’s units; they were prioritized using a custom-made risk-ranking model, taking into account the frequency of exposure, number of workers exposed, effectiveness of existing control measures, volume of chemical exposed, and potential health consequences. The risks were also prioritized for the individual worker, by omitting the number of workers exposed factor from the risk model. The model categorized the hazards as low, moderate, or high. High hazards were identified as needing further investigation and implementation of control measures, if exposure levels exceed regulated occupational exposure limits. A model validation step was also included to confirm the results of applying the model, before it was extended to other units in the refinery. The chemical exposure risk prioritization and assessment model was validated with industrial hygiene monitoring, by examining hazards in all three risk classification categories. The model therefore will provide an accurate and simple means both to rule out the low risks and to prioritize the higher ranked risks for workplace monitoring at any of the refinery’s units. A template of the risk prioritization and assessment model will be made available, as we hope this model will be applicable to other industrial workplaces.
M. Ramsey, Liberty Mutual Group, Wayne, PA.
Accidental worker exposure can occur from unplanned gas releases into a work space due to equipment failure, physical damage, worker error, or inadequate procedures. Having reasonable estimates of the amount of time required for atmospheric concentrations to reach certain target concentration levels — such as immediately dangerous to life or health (IDLH), permissible exposure limit, threshold limit value, and so on — is an important consideration when assessing the degree of hazard presented by unplanned gas releases. The continuity equation for air contaminants was used to develop an Excel spreadsheet to judge the risk presented by hypothetical accidental releases of nitrogen. To accommodate calculations of oxygen concentrations instead of contaminant concentrations, modifications were made in the continuity equation as presented in ACGIH’s Industrial Ventilation: A Manual of Recommended Practice.
The assessment spreadsheet allows calculation of (1) volume of gas stored in a room (when the gas equilibrates to room temperature and pressure); (2) equilibrium concentration achievable in a space and the potential for a gas release to result in a specified target concentration; (3) time required to reach target concentrations; and (4) relationship between room size, number of air changes, and the time required to reach a specified concentration. Examples of scenarios will be provided. The information provided in the spreadsheet assisted in the assessment of the risk presented by hypothetical release scenarios and the assessment of the need for further controls to reduce risk. Control recommendations that resulted from this assessment have included physical changes in gas handling systems, modifications in ventilation, procedural changes, system monitoring, training and communication, and personal protective equipment.
H. Frazer, ESIS Global Risk Control Services, Phoenix, AZ.
There are commercial flow splitters available for collecting multiple tube samples using one pump, but none is available for multiple particulate sampling. In certain situations it is beneficial to be able to collect two particulate samples on the same individual using one sampling pump. Using one pump is less stress on the employee and requires less equipment for the industrial hygienist. When assessing exposure to welders conducting stainless steel welding, it is desirable to be able to sample simultaneously on a mixed cellulose ester (MCE) filter for metallic welding fumes and a polyvinyl chloride (PVC) filter for hexavalent chromium. Another process that requires the need for multiple dust filters is rosin solder fume (as colophony) and lead fume/particulate. Although two pumps could be used, it requires twice as much equipment and employees resist wearing two pumps, especially if their job requires active climbing or maneuvering around equipment in tight, enclosed spaces. A simple, economical method was developed using a Y-connector to “split” the vacuum from a single personal sampling pump through two dust cassettes. The Y-connector and multiple filter combinations were tested to determine if it was practical to use and would allow collection of appropriate volumes of air (in both duration of operation and flow rate) for good detection limits for each analytical analysis. A method will be presented on how to “adjust” the airflow at each sampling leg/filter by changing the resistance of each leg. Field trials with multiple filter configurations were conducted to determine adjustment for flows, worker acceptance, flow reliability, and overall durability of the method. The field tests demonstrate this method is easy, provides accurate flows, and can provide a method to assess multiple particulate exposures using a single sampling pump.
J. Kenny, ESIS Environmental Health Lab, Cromwell, CT; H. Cohen, University of New Haven, New Haven, CT.
The ACGIH’s Threshold Limit Value (TLV) Committee has been moving toward replacing many of its single-value aerosol standards with standards for inhalable, thoracic, and respirable dust fractions. There are now 21 compounds including wood dust that specify the inhalable dust fraction collection as the TLV. Existing inhalable samplers are far more expensive that traditional 37-mm cassette samplers. Also, ordering, special handling, and setting up inhalable samplers can be perceived as an inconvenience by the end user. Because of the cost and inconvenience of available inhalable samplers, a new disposal inhalable sampler was designed. Our new device was designed to address these issues and use the same linear capture velocity of the existing SKC IOM and SKC Button inhalable samplers. Our device also offers vertical elutriation, through the use of an extended cowl, which should reduce the positive interfering effect of projectile particles that can bias inhalable samplers. We tested the new inhalable sampler side by side with the IOM sampler in a woodworking shop. Twenty-four side-by-side samples were taken along with eight duplicate samples (each device sampled in duplicate). Dust concentrations ranged from 0.1-3.0 mg/m3 in the woodworking shop. Analyses revealed that results were not statistically different (p<0.05), although the new sampler provided results that were approximately 10-15% lower. Regression analyses of the two sampling devices indicated an excellent correlation (R2 = 0.90). Analyses of paired results indicated that the new sampler had approximately half the variability of the IOM sampler. These results suggest that it is possible to provide industrial hygienists with a low-cost, disposable inhalable sampler that is capable of performing at least as well as traditional devices on the market. Plans are under way to conduct additional testing in workplaces that have a variety of different aerosol contaminants.
A. Buck, C. Loomis, A.P. Buck Inc., Orlando, FL.
Traditional sampling for contaminates in the air requires accurate flow measurements of the vacuum being drawn through a collection device. Historically, this has been done using a classic soap film calibrator. These devices only took a single flow measurement as the soap film passed up the fixed volume of the flow cell. This technique provides a volumetric flow reading with an accuracy of 0.5%. It also provides true flow at any altitude. Rotary lobe pumps have been used for years as high-volume air pumps and liquid pumps. By miniaturizing this positive displacement device and monitoring the revolution per minute, the precise flow rate can be measured. Since the air is being chopped into discrete parcels and counted as passed on through the device, no pressure spikes or pulses occur as with other styles such as a dry piston calibrator.
Spur gears are attached to the rotating shafts to synchronize the lobes, which keeps the lobes from touching during rotation and prevents wearing of the lobe shape. Flow range is determined by the diameter and length of the lobes. An electric motor is attached to one of the shafts on the outside of the rotary lobe’s chamber. A microprocessor controls the speed of the rotating lobes until the pressure drop across the lobe chamber is no more than one inch of water pressure. This ensures a minimal backpressure load on the air stream. Today’s dry calibrators with high loads and pulsation can negatively affect a sampling pump’s accuracy. These rotating lobe flowmeters are a positive displacement device and therefore are accurate for measuring volumetric flow at any altitude. An accuracy of 0.1% can be achieved with this technique.
E. Stevenson, E. Patricio, Liberty Mutual Insurance Co., Hopkinton, MA.
On Feb. 28, 2006, OSHA significantly lowed its permissible exposure limit (PEL) for hexavalent chromium (CrVI) compounds from 100 µg per cubic meter (µg/m3) measured as CrO3 as a ceiling limit to 5 µg/m3 measured as CrVI, based on an 8-hr time-weighted average (TWA), and established an action level at 2.5 µg/m3. The new PEL is lower than the ACGIH threshold limit values (TLV-TWA) and does not distinguish between soluble and insoluble CrVI, as does the TLV. In addition to inhalation exposure assessment, OSHA has separate paragraphs for establishing regulated work areas and ensuring that eating and drinking areas and surfaces are maintained as free as practicable of Chrome VI. OSHA has established an air sampling method as well as wipe and bulk sampling methods. This presentation is developed from past experience from field collection and laboratory analysis of chromium. To correctly evaluate inhalation, skin contact and ingestion exposure potential, the industrial hygienist (IH) must understand the following: (1) some operations are more likely to produce CrVI in the workplace; (2) different operations and work practices may release either soluble or insoluble Chrome VI (Differences are seen even between different types of welding on stainless steel.); (3) Cdllection and analysis of soluble and insoluble Chrome VI differ, and communication between the IH and the IH laboratory is critical to proper workplace evaluations; and (4) some sampling and collection considerations reduce the conversion of Cr+6 to Cr+3.
E. Lee, M. Harper, J. Nelson, NIOSH, Morgantown, WV; P. Hintz, NIOSH, Spokane, WA.
The GK2.69 cyclone has been developed and used for both respirable and thoracic particle sampling application. In this study, area samples were taken from six stations in an ore processing mill, at a mine whose ore contains amphibole minerals, to compare fiber concentrations from the GK2.69 sampler (used with 37-mm filter cassette) against the 25-mm cowled sampler (current NIOSH 7400 standard method). At each station, four area samples were taken using the two samplers (24 paired samples). Slides were prepared using the dimethylformamide/Euparal technique and recently commercially available relocatable cover slips. Two counters examined the slides using a phase contrast microscope. Prior to counting the samples, four reference slides were randomly selected and counted three times on different days to compare the coefficient of variation (CV) within and between counters. For the reference slides, the CV between counters (0.04-0.33) showed slightly higher than the CVs within counters (0.01-0.10 for counter-A and 0.01-0.20 for counter-B). Overall, fiber concentrations collected from the GK2.69 sampler were higher than those from the cowled sampler, except for 3 out of 24 paired-samples (concentration ratio (CGK2.69/CCowled): 0.60-6.72). A Pearson’s correlation coefficient of 0.913 indicated a good correlation between the two samplers. A statistically significant correlation was observed from the linear regression analysis (p-value: <0.0001, R-square: 0.8339) between the two samplers; the fiber concentration of the GK2.69 sampler was about 1.32´ higher than the cowled sampler concentration, which is possibly inconsistent with a previous study by other researchers that evaluated the performance of different thoracic samplers in laboratory tests. Analysis of further field samples would be necessary to investigate uncertainties, such as the influence of the homogeneity of fiber deposition over the filters, on the results. In addition to many more samples from this site being available for analysis, samples are being collected at additional sites.
M. Simmons, OSHA, Sandy, UT.
OSHA required an active sampler for the collection and measurement of hydrogen sulfide gas in the workplace that was free of sampling and analytical interferences. This sampler was easily prepared and analyzed in the laboratory, and it could collect both 15-min ceiling and 4-hr time-weighted average samples. Following OSHA Evaluation Guidelines for Air Sampling Methods and using a controlled test atmosphere, a new 8-cm long glass sampler was developed and tested. The sampler consists of two prefilters, used to scrub particulates and sulfur dioxide, followed by two sections of silver nitrate coated silica gel. During sampling, hydrogen sulfide reacts with the silver nitrate to form silver sulfide. The resultant sulfide is extracted from the silica gel using an alkaline cyanide solution, converted to sulfate using hydrogen peroxide and analyzed by ion chromatography using a conductivity detector. Based on the evaluation results obtained, the new sampler was found to be acceptable for the collection and measurement of hydrogen sulfide gas in the workplace.
K. Kirollos, T. Tekleab, G. Mihaylov, Microteq, LLC, Virginia Beach, VA.
Red phosphorus is a dangerous substance widely used in clandestine labs for methamphetamine synthesis. Fatal incidents are widespread in using the red phosphorus method for methamphetamine synthesis. Law enforcement officers and firefighters are under imminent threat when entering the methamphetamine labs, due to the potential formation of phosphine on the headspace of red phosporus containers. In this work, a colorimetric direct-read device and method have been developed for detecting traces of red phosphorus on surfaces. The device includes a 7.1 cm2 swab and a 15 cm3 developing jar. A predetermined amount of reagent is patched inside the developing jar, and a chemical sensor selective to red phosphorus has been incorporated on the exterior part of the jar, where the chemical sensor is exposed to the contents in the jar through a pinhole. A precalibrated scale for length of stain has been designed adjacent to the chemical sensor. Using the swab, traces of red phosphorus are collected from any surface, and the swab is placed in the developing jar. Upon addition of the developing solution, a brown-reddish length of stain develops on the sensor that is proportional to the amount of red phosphorus collected from the surface. The minimum detection limit of red phosphorus is 0.1µg. The device has been validated for red phosphorus concentration range of 0.1µg to 2 µg.
T. Tekleab, G. Mihaylov, K. Kirollos, Microteq, LLC, Virginia Beach, VA.
Over 17,000 clandestine labs are discovered every year in the United States. Law enforcement personnel and firefighters entering these labs are under imminent danger of exposure to a wide range of toxic gases and vapors. Further, to ensure the safety of people reoccupying these facilities after remediation, it is mandatory to establish the cleanliness by checking for traces of toxic substances that may still exist in the facility. In this work, a comprehensive air sampling system is developed and validated for simultaneous, selective, and on-site detection of acetic and hydrochloric acids, ammonia, iodine, phosphine, phosgene, and total organics. The system also includes sorption media (charcoal, silica gel, and Microlite) for the collection of organic gases and vapors, inorganic gases, and mercury vapors. The system mainly consists of a manifold with pistol-grip handle holding seven detector tubes and two sorption tubes connected to one push-button electric sampling pump. Within 5 min, the system is capable of detecting acetic acid (2.5 ppm to 10 ppm), ammonia (5 ppm to 50 ppm), HCl (2.5 ppm to 10 ppm), phosphine (0.1 ppm to 2.5 ppm), phosgene (0.05 ppm to 3 ppm), and iodine (0.05 ppm to 3 ppm). The total organic detector is validated for acetone (100 ppm to 800 ppm), toluene (10 ppm to 400 ppm), ethanol (200 ppm to 1400 ppm), methanol (1 ppm to 20 ppm), naphtha (2 ppm to 25 ppm), and ethers (5 ppm to 25 ppm). Within 2 min the system is capable of detecting the targeted substances at the threshold limit value levels or higher. The operation of the system was tested and validated at temperatures ranging from 5ºC to 40ºC and relative humidities ranging from 10 to 85.
T. Tekleab, G. Mihaylov, K. Kirollos, Microteq, LLC, Virginia Beach, VA.
Occupational exposure to chromium (VI) causes dermatitis, skin ulceration, and perforation of the nasal septum. Once it is absorbed into the human body, it targets blood, liver, and kidney. The main exposure routes for dusts and aerosols of chromium are inhalation and direct contact with the skin. There is a great need for on-site, real-time monitoring of chromium (VI) on occupational work areas. In this work, a colorimetric direct-read device and a method have been introduced for detecting traces of hexavalent chromium on any surface. The device includes a 1.5-cm2 swab and a color comparator that includes a color scale and a gray scale. The hexavalent chromium detecting element is incorporated in the swab. The vacuum applicator is used for holding the swab and swiping a surface area of 10 cm2. By applying one drop of a developing solution on the swab, a distinctive color change shows the presence of hexavalent chromium. A simplified color comparator was designed to read the intensity of the color for quantification of the hexavalent chromium. To compensate the color-masking effect of dirt, a gray scale was incorporated in the color comparator, which is used by matching the color scale with gray scale to match the color on the swipe. Based on the calibration of the device, a color reading value for each match of colors could be determined. The device was calibrated for hexavalent chromium concentration ranges of 0.05 µg to 10 µg. Laboratory experiments conducted to calibrate the device showed a mean coefficient of variation of 12% and a bias of 4.3%.
L. Coyne, SKC Inc., Eighty Four, PA.
Air sampling bags are used in a variety of applications in industrial hygiene and ambient air sampling. Bags are an inexpensive and simple option for collecting single or multiple component mixtures and for the calibration of direct-reading instruments. One drawback with using bags for sample collection is that bag materials can outgas and confound analytical measurements of the bag contents. Tedlar, for example, has been shown to outgas phenol and dimethyl acetamide. Other potential issues include bag and compound incompatibility and integrity of the sample in extended storage. This paper will investigate the ability of the new SKC FlexFilm to provide improved properties for sample collection compared to Tedlar film. For purposes of comparative testing, 1-L bags were made from the test film and polypropylene fittings. Stability tests were performed using gases from several classes of compounds. Various concentrations of the test gases were prepared in the bags. Analyses of the bag contents were performed at 1-, 2-, 4-, and 7-day intervals, using direct-injection into a gas chromatograph with flame ionization detection (GC/FID). Bag outgassing was tested by filling the bags with air and analyzing the bag contents by gas chromatography-mass spectrometry (GC/MS). The data show that the total volatile organic compounds (VOCs) outgassed from SKC FlexFilm were 877 µg/M3 compared with 2730 µg/M3 for Tedlar. Storage studies indicate that 21 test gases have recoveries greater than 80% after 2-day storage in bags made from the new film. Many of the test gases were stable for 7 days. In conclusion, the new film was found to be suitable as an air sampling bag. It offers the advantage of lower VOC background and longer holding times for many compounds when compared with Tedlar film bags. This new film provides a new option for sample collection using sample bags.