Recommended Practices: Protecting Temporary Workers

[Excerpt] Workers employed through staffing agencies are generally called temporary or supplied workers. For the purposes of these recommended practices, “temporary workers” are those supplied to a host employer and paid by a staffing agency, whether or not the job is actually temporary. Whether temporary or permanent, all workers always have a right to a safe and healthy workplace. The staffing agency and the staffing agency’s client (the host employer) are joint employers of temporary workers and, therefore, both are responsible for providing and maintaining a safe work environment for those workers. The staffing agency and the host employer must work together to ensure that the Occupational Safety and Health Act of 1970 (the OSH Act) requirements are fully met. See 29 U.S.C. § 651. The extent of the obligations of each employer will vary depending on workplace conditions and should therefore be described in the agreement or contract between the employers. Their safety and health responsibilities will sometimes overlap. Either the staffing agency or the host employer may be better suited to ensure compliance with a particular requirement, and may assume primary responsibility for it. The joint employment structure requires effective communication and a common understanding of the division of responsibilities for safety and health. Ideally, these will be set forth in a written contract. OSHA and NIOSH recommend the following practices to staffing agencies and host employers so that they may better protect temporary workers through mutual cooperation and collaboration. Unless otherwise legally required, these recommendations are for the purpose of guidance and in some cases represent best practices

Guidelines for the control and monitoring of methane gas on continuous mining operations

"Until the early 1980s, mine face ventilation systems were designed for ventilating cutting depths up to 20 feet. Since that time, use of remotely operated mining machines have allowed cutting depths to increase to 40 ft, increasing concerns about the effects on methane levels at the mine face area. The principles for efficient methane control during deeper cutting remained the same, namely: 1. Move a sufficient quantity of intake air from the end of the tubing or curtain to the face. 2. Mix intake air with methane gas liberated at the face. 3. Move methane contaminated air away from the face. However, when cutting to depths greater than 20 ft (known as deep-cut mining), airflow quantities reaching the face area often decreased because it was difficult to maintain tubing or brattice setback distances. Earlier research showed that use of machine-mounted scrubbers and water sprays increased airflow at the face area during deep cutting. NIOSH research examined how these and other factors affected face airflow. A full-scale ventilation test gallery was used to study how different operating conditions caused airflow patterns and methane distributions near the face to vary. The research results showed that during deep-cut mining: 1. Without additional controls, only a small percentage of the air delivered to the end of the tubing or curtain reached the face area. 2. Operation of a machine-mounted scrubber increased airflow and reduced methane levels at the face area as long as the quantity of intake air delivered to the end of the curtain or tubing was not reduced. 3. Operation of water sprays did not significantly increase the volume of air reaching the face but did improve mixing of methane and intake air at the face. Methane monitoring requirements remained the same for deep cutting, but the possibility of rapidly changing conditions at the face increases the need for accurate estimates of face methane concentration. Research examined currently available instrumentation and sampling methods for monitoring methane at the face. The results from this NIOSH research program demonstrate how existing and new engineering controls can be used to (educe face methane levels. The sampling methods that were investigated can provide better ways to measure methane levels near the front of the continuous mining machine. In this report several practical guidelines are recommended for controlling and monitoring methane levels in the face areas of underground coal mines. Most of the recommendations were based on studies conducted in the NIOSH ventilation test gallery. 1. Free-standing fans can be used to ventilate empty headings in coal mines; a) The fan nozzle should be designed to provide maximum throw distance. b) Recirculation should be minimized by proper placement of fan inlet and or by placing curtains partway across the entry. 2. With blowing systems, the single most important factor on face methane dilution is the velocity of the air directed toward the face; a) For the same airflows, use of tubing rather than a curtain usually provides better control of face methane, especially at longer setback distances. 3. With blowing and exhausting systems, and with the mining machine at the face, use of scrubbers increases the amount of intake airflow reaching the mining face; a) Scrubber and spray systems should be designed to achieve efficient face ventilation for the effective removal of gas from the face. 4. Measurement of airflow speed and direction between the curtain and the face helps to predict methane concentrations in the face area; a) In empty entries, airflow velocity is much lower in narrower entries. More airflow should be provided during box cuts to prevent higher methane levels. 5. Regardless of intake flow quantity, increasing scrubber flow will reduce face methane levels if recirculation is controlled. Recirculation can be controlled by; a) Minimizing leakage around the ventilation curtain; b) Directing scrubber exhaust away from the blowing curtain. With exhaust systems the mouth of the curtain should always be outby the scrubber exhaust. 6. Water sprays on the mining machine should be directed to provide the best airflow across the entire face. 7. Methanometer response times can be measured using either of two techniques developed by NIOSH. Instruments with shorter response times more accurately measure current methane levels. Dust cap design has the greatest effect on response times; a) When selecting a methanometer the dust cap design should be examined. The cap should protect the methane sensor from dust and water but not significantly increase the response time. 8.Alternative methane sampling locations on the mining machine should be compared and selected based on the relative protection provided to the face workers. 9. Mine personnel should be provided with methane monitors that can be worn while working in areas that cannot be regularly monitored. Audible, visual, and vibratory alarms for the monitors should be evaluated based on the environment in which the instruments are used. 10. Miners must be safely removed from a mine without exposure to excessive methane following stoppage of a main fan; a) Mines should be evaluated for the most likely area where methane gas can accumulate following stoppage of a main mine fan. 11. In areas between the mouth of the ventilation curtain and the face, airflow direction is constantly changing and it is difficult to accurately measure flow velocity with a single-axis anemometer (e.g., a vane anemometer); a) Following approval for underground use, multi-axis anemometers should be used to monitor airflow direction and velocity between the mouth of the ventilation curtain or tubing and the face. Multi-axis instruments should also be used to monitor flow at locations outby the mining face. 12. During roof bolting, if it is not practical to monitor methane levels at the mining face, methane levels should be measured with a bolter machine-mounted monitor and a detector held 16 ft inby the last row of bolts using a extensible pole." - NIOSHTIC-2by Charles D. Taylor, J. Emery Chilton, Gerrit V.R. Goodman."April 2010."Also available via the World Wide Web.Includes bibliographical references (p. 71-75).Includes bibliographical references and index

Coal dust explosibility meter evaluation and recommendations for application

"This report details the results of a NIOSH investigation on the ability of the Coal Dust Explosibility Meter (CDEM) to accurately predict the explosibility of samples of coal and rock dust mixtures collected from underground coal mines in the U.S. The CDEM, which gives instantaneous results in real time, represents a new way for miners and operators to assess the relative hazard of dust accumulations in their mines and the effectiveness of their rock dusting practices. The CDEM was developed by the National Institute for Occupational Safety and Health (NIOSH) and successfully underwent national and international peer review. The intention of the device is to assist mine operators in complying with the Mine Safety and Health Administration (MSHA) final rule 30 CFR* 75.403, requiring that the incombustible content of combined coal dust, rock dust, and other dust be at least 80% in underground areas of bituminous coal mines. As a final step towards commercialization of the CDEM, and to evaluate the performance of the device as a potential compliance tool, NIOSH undertook an extensive cooperative study with MSHA. This study, completed in 2009-2010, involved field use of the CDEM within MSHA's 10 bituminous coal districts. As part of their routine dust compliance surveys in these districts, MSHA inspectors collected sample coal and rock dust mixtures, field testing these samples for explosibility with the CDEM. Samples were then sent to the MSHA National Air and Dust Laboratory at Mt. Hope, WV, for parallel testing, first using a drying oven to determine the moisture followed by the traditional low temperature ashing (LTA) method. The LTA method determines explosibility of a coal and rock dust sample in a laboratory by heating the mixture to burn off the combustible material. The results, when combined with the moisture, are reported as total incombustible content (TIC). If the TIC is . 80%, the sample is deemed to be nonexplosible and compliant with 30 CFR 75.403. In the field component of this study, MSHA's use of the CDEM indicated that 30% (175) of the 591 samples collected were explosible. NIOSH was able to obtain and remeasure 297 samples, and 97% of those identified by the CDEM as being explosible (27% of samples) or nonexplosible (73% of samples) correlated with the results of the subsequent lab analysis using the LTA method. Of the remaining 3% where there were differences between the field and laboratory methods, subsequent NIOSH evaluation attributed these differences to the variability (incomplete mixing, inadequate drying of the sample, the particle size of the rock dust and/or coal dust) of the samples being analyzed, the retained moisture in those samples, and the inherent ash in the coal. In considering these results and comparing the CDEM field measurements to the LTA laboratory measurements, it is important to understand the fundamental distinctions between the two methods. The determination of TIC by the LTA method is not itself a direct measure of explosibility, but a surrogate that calculates a single parameter associated with full-scale experimental results. This method is not based on particle size and treats all particles equally regardless of the size. In contrast, the CDEM utilizes a different approach, using optical reflectance to determine the ratio of rock dust to coal dust in a mixture, with full-scale experiments on flame propagation having already demonstrated the effects of varying the coal dust particle sizes and incombustible concentrations on the explosible vs. nonexplosible dust mixtures. A final important distinction between the two methods is that the CDEM offers real-time measurements of the explosion propagation hazard within a coal mine entry, allowing for immediate identification and mitigation of the problem, while the results from the traditional LTA method are not known for days or weeks after a sample is collected, allowing for the deficiency in rock dust to continue. The conclusions of this study strongly support the field use of the CDEM to measure the explosibility of coal and rock dust mixtures, to more effectively improve the onsite adequacy of rock dusting for explosion prevention. Mine operators could use the CDEM on a regular basis to ensure that their rock dusting practices are achieving inertization requirements and meeting the intent of 30 CFR 75.403. MSHA inspectors could use the CDEM as a tool to immediately identify onsite explosibility hazards and initiate corrective action. A critical issue to both the LTA and the CDEM analysis methods is that the results are dependent on representative samples being collected for analysis." - NIOSHTIC-2Executive summary -- Introduction -- Background on coal dust and explosibility testing -- CDEM 0peration -- Comparison of laboratory results and CDEM results -- Joint study between NIOSH and MSHA -- Results and discussion -- GREEN measurements -- RED/YELLOW measurements -- Conclusions from the NIOSH study -- Commercial CDEM development -- Calibration and programming of the commercial CDEM -- Commercial CDEM changes based on potential customer concerns -- The Commercial CDEM as a verification and compliance tool -- NIOSH recommendations -- Acknowledgments -- References -- APPENDIX A: CDEM design -- APPENDIX B: CDEM training -- APPENDIX C: Prototype CDEM calibration and testing procedures used in the joint study -- APPENDIX D: Particle size effect -- APPENDIX E: MSHA inspector questions and commentsMarcia L. Harris, Michael J. Sapko, Floyd D. Varley, and Eric S. Weiss"August 2012."Also available via the World Wide Web.Includes bibliographical references (p. 25-26)

Best practices for dust control in metal/nonmetal mining

"Respirable silica dust exposure has long been known to be a serious health threat to workers in many industries. Overexposure to respirable silica dust can lead to the development of silicosis - a lung disease that can be disabling and fatal in its most severe form. Once contracted, there is no cure for silicosis so the goal must be to prevent development by limiting a worker's exposure to respirable silica dust. In addition, the International Agency for Research on Cancer (IARC) has concluded that there is sufficient evidence to classify silica as a human carcinogen. For workers in the metal/nonmetal mining industry, the Mine Safety and Health Administration (MSHA) regulates and monitors exposure to respirable silica dust through personal dust sampling. Recent MSHA personal sampling results indicate that overexposures to respirable silica dust continue to occur for miners in metal/nonmetal mining operations. From 2004 to 2008, the percentages of samples that exceeded the applicable respirable dust standard for the different mining commodities were: 1. 12% for sand and gravel; 2.13% for stone; 3.18% for nonmetal; 4.21% for metal. Of the 2,407 deaths attributed to silicosis in the United States frm 1990-1999, employment information was available for 881 deaths. Metal/nonmetal mining was the industry recorded for over 15% of these 881 deaths, with mining machine operator the most frequently recorded occupation. In light of ongoing silica overexposures and reported silicosis deaths in metal/nonmetal miners, an ongoing threat to miners' health is evident. This handbook was developed to identify available engineering controls that can assist the industry in reducing worker exposure to respirable silica dust. The controls discussed in this handbook range from long-used controls which have developed into industry standards, to newer controls, which are still being optimized. The intent is to identify the "best practices" that are available for controlling respirable dust levels in underground and surface metal/nonmetal mining operations. This handbook provides general information on the control technologies along with extensive references. In some cases, the full reference(s) will need to be accessed to gain in-depth information on the testing or implementation of the control of interest. The handbook is divided into five chapters. Chapter 1 discusses the health effects of exposure to respirable silica dust, while Chapter 2 discusses dust sampling instruments and sampling methods. Chapters 3, 4 and 5 are focused upon dust control technologies for underground mining, mineral processing, and surface mining, respectively. Finally, it must be stressed that after control technologies are implemented, the ultimate success of ongoing protection for workers is dependent upon continued maintenance of these controls. On numerous occasions, National Institute for Occupational Safety and Health (NIOSH) researchers have seen appropriate controls installed, but worker overexposures continued to occur in the absence of proper maintenance of these controls." - NIOSHTIC-2by Jay F. Colinet, Andrew B. Cecala, Gregory J. Chekan, John A. Organiscak, and Anita L. Wolfe."May 2010."Also available via the World Wide Web.Includes bibliographical references (p. 72- 75)

Recommendations for a new rock dusting standard to prevent coal dust explosions in intake airways

"The workings of a bituminous coal mine produce explosive coal dust for which adding rock dust can reduce the potential for explosions. Accordingly, guidelines have been established by the Mine Safety and Health Administration (MSHA) about the relative proportion of rock dust that must be present in a mine's intake and return airways. Current MSHA regulations require that intake airways contain at least 65% incombustible content and return airways contain at least 80% incombustible content. The higher limit for return airways was set in large part because finer coal dust tends to collect in these airways. Based on extensive in-mine coal dust particle size surveys and large-scale explosion tests, the National Institute for Occupational Safety and Health (NIOSH) recommends a new standard of 80% total incombustible content (TIC) be required in the intake airways of bituminous coal mines in the absence of methane. MSHA inspectors routinely monitor rock dust inerting efforts by collecting dust samples and measuring the percentage of TIC, which includes measurements of the moisture in the samples, the ash in the coal, and the rock dust. These regulations were based on two important findings: a survey of coal dust particle size that was performed in the 1920s, and large-scale explosion tests conducted in the U.S. Bureau of Mines' Bruceton Experimental Mine (BEM) using dust particles of that survey's size range to determine the amount of inerting material required to prevent explosion propagation. Mining technology and practices have changed considerably since the 1920s, when the original coal dust particle survey was performed. Also, it has been conclusively shown that as the size of coal dust particles decreases, the explosion hazard increases. Given these factors, NIOSH and MSHA conducted a joint survey to determine the range of coal particle sizes found in dust samples collected from intake and return airways of U.S. coal mines. Results from this survey show that the coal dust found in mines today is much finer than in mines of the 1920s. This increase in fine dust is presumably due to the increase in mechanization. In light of this recent comprehensive dust survey, NIOSH conducted additional large-scale explosion tests at the Lake Lynn Experimental Mine (LLEM) to determine the degree of rock dusting necessary to abate explosions. The tests used Pittsburgh seam coal dust blended as 38% minus 200 mesh and referred to as medium-sized dust. This medium-sized blend was used to represent the average of the finest coal particle size collected from the recent dust survey. Explosion tests indicate that medium-sized coal dust required 76.4% TIC to prevent explosion propagation. Even the coarse coal dust (20% minus 200 mesh or 75 microm), representative of samples obtained from mines in the 1920s, required approximately 70% TIC to be rendered inert in the larger LLEM, a level higher than the current regulation of 65% TIC. Given the results of the extensive in-mine coal dust particle size surveys and large-scale explosion tests, NIOSH recommends a new standard of 80% TIC be required in the intake airways of bituminous coal mines in the absence of methane. The survey results indicate that in some cases there are no substantial differences between the coal dust particle size distributions in return and intake air courses in today's coal mines. The survey results indicate that the current requirement of 80% TIC in return airways is still appropriate in the absence of background methane." - NIOSHTIC-2Kenneth L. Cashdollar, Michael J. Sapko, Eric S. Weiss, Chi-Keung Man, Samuel P. Harteis, and Gregory M. Green."May 2010."Also available via the World Wide Web at the National Institute for Occupational Safety and Health web site.Includes bibliographical references (p. 23-26)

Strategies for escape and rescue from underground coal mines

"Section 2 of the Mine Improvement and New Emergency Response Act of 2006 (2006 MINER Act), Public Law 109-236, [MINER Act 2006] directed operators of underground coal mines to improve accident preparedness and response. This report summarizes the findings of research conducted by the National Institute for Occupational Safety and Health (NIOSH) between December 2007 and March 2009 to identify the attributes of an improved escape and rescue system. This report focuses on specific guidelines for escape and rescue from underground coal mines during fire and explosion incidents and contains an investigation of United States and worldwide mine practices. The basic elements of a mine emergency response system (escape, rescue, and incident command) are addressed. Further, knowledge gaps, training, human behavior, and technology challenges are also identified. This report presents a strategy of self-escape and safe-rescue including incident command as an integrated system with consideration given to U.S. underground coal mine demographics. The findings are intended to facilitate the evolution of all miners' capabilities and support institutions so that they will have a greater chance of successfully managing abnormal incidents without injury or fatalities." - NIOSHTIC-2by Danrick W. Alexander, Susan B. Bealko, Michael J. Brnich, Kathleen M. Kowalski-Trakofler, Robert H. Peters."February 2010."Available on the internet at the cdc.giv website; verified 3-17-10.Includes bibliographical references (p. 47-51

Injuries among youth on farms, 2001

"Agriculture continues to rank as one of the most hazardous industries. Youth are exposed to hazards while living, working on, or visiting farms. In 2001, there were approximately 1.9 million farms in the U.S., with an estimated 1,075,759 youth living in these farm households. Between 1995 and 2000, the annual injury fatality rate for youth on farm operations was 9.3 fatalities per 100,000 youth. In 2001, the non-fatal injury rate for youth who reside on or are hired to work on U.S. farms was 1,270 injuries per 100,000 farm youth. Household farm youth comprise all youth 0-19 years of age who live on Us. farms and include working and non-working youth. An estimated 1,075,759 youth lived on u.S. farm operations in 2001: 16,851 were injured (16 injuries per 1,000 household youth); 10-15 year olds had the highest injury rate (21 injuries per 1,000 household youth); 5,807 injuries occurred while working on the farm (10 injuries per 1,000 working household. youth); 10-15 year olds experienced the highest rate of injury while doing farm work (11 injuries per 1,000 household youth)." --NIOSHTIC-2Title from PDF title screen (CDC, viewed July 8, 2010)."December 2004."Also available on the World Wide Web

Occupational Health and Safety Prevention Plan in Water Treatment Plant

The research was carried out at the "El Guarumo" drinking water plant located in Santa Ana, province of Manabí, Ecuador. The objective of the investigation was the proposal of a plan of prevention of occupational risks that allows the management of the labor risks in said plant. The main tools used were: survey, interview, checklist, LEST questionnaire for the diagnosis of the current situation in terms of working conditions, the risk identification matrix and the binary method of risk assessment. The main results obtained were the identification of the risks in their different categories, observing that the critical risk factors are related to the physical overexertion, the uncomfortable postures and the manual lifting of the load. Among the important risks are falling objects, skin contact with toxic substances and mental overwork, closely related to work pressures and job security? It was possible to carry out the proposal of preventive and corrective measures in order to properly manage the risks and contribute to the safety and health of the workers