"Construction workers may be exposed to hazardous dust containing crystalline silica during site preparation when drilling systems are used. The National Institute for Occupational Safety and Health (NIOSH) found that drill dust could be decreased by using wet or dry dust reduction engineering controls, enclosed cabs, and implementing a dust control program." - NIOSHTIC-2"The principal contributors to this publication were John Organiscak, Andrew Cecala, and Steven Page of the Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health. John Whalen under a contract with the U.S. Public Health Service, Division of Federal Occupational Health served as writer/editor." - acknowledgements"April 2009."Also available via the World Wide Web

Pittsburgh Research Laboratory (National Institute for Occupational Safety and Health)

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"Construction workers may be exposed to hazardous dust containing crystalline silica during site preparation when drilling systems are used. The National Institute for Occupational Safety and Health (NIOSH) found that drill dust could be decreased by using wet or dry dust reduction engineering controls, enclosed cabs, and implementing a dust control program." - NIOSHTIC-2"The principal contributors to this publication were John Organiscak, Andrew Cecala, and Steven Page of the Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health. John Whalen under a contract with the U.S. Public Health Service, Division of Federal Occupational Health served as writer/editor." - acknowledgement

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DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Institute for Occupational Safety and HealthSummaryConstruction workers may be exposed to hazardous dust con-taining crystalline silica during site preparation when drilling systems are used. The National Institute for Occupational Safety and Health (NIOSH) found that drill dust could be decreased by using wet or dry dust reduction engineering controls, enclosed cabs, and implementing a dust control program.Reducing Hazardous Dust Exposure When Rock Drilling During ConstructionDescription of ExposureBreathing dust that contains crystal-line silica can lead to silicosis, a deadly lung disease. No effective treatment exists for silicosis, but it can be pre-vented by controlling workers’ expo-sures to dust containing crystalline sil-ica. Exposure to crystalline silica has also been linked to lung cancer, kid-ney disease, reduced lung function, and other disorders [NIOSH 2002]. Many tasks in construction may gen-erate dust containing crystalline silica: grinding or cutting concrete, tuck-pointing masonry, using a jackham-mer to break concrete, or when using drilling systems during construction. Rock drilling before blasting for high-way construction may generate a large amount of dust containing crystal-line silica.  Also, rock drilling for oth-er reasons during construction such as site preparation, pipeline installa-tion, or water well drilling may gen-erate hazardous dust (see Figure 1). Acute and accelerated cases of silico-sis have been reported in rock drill-ers [NIOSH 1992]. NIOSH [1996] noted that a drill operator working at a building site where no dust con-trols were used was exposed to 16 times the NIOSH recommended ex-posure level (REL).  NIOSH Studies and ControlsNIOSH has conducted studies in the construction and mining industries where rock drilling is done. Engineer-ing controls and work practices iden-tified in these studies help prevent Rock drilling without appropriate dust control.Figure 1. silicosis by keeping dust containing crystalline silica out of the air workers may breathe (see Figure 2). NIOSH recommends that the same controls and work practices, described below, be used in construction activities where rock drilling may generate silica dust.Under federal occupational safety and health regulations, employers have the responsibility for implementing en-gineering controls and administrative controls, providing personal protective equipment, and providing safety and health training for employees.  Site set-upDevelop a site-specific safety and health plan. The plan  should include guidance for recognizing when silica dust may be generated and describe strategies to control or eliminate dust. Include engineering controls, personal protective equipment, and work practices.During rock drilling operations, use wet or dry con- trol systems to control dust. Wet systems are efficient but may freeze in the winter. Caution is advised when using wet systems in the presence of electrical ener-gy sources. When purchasing equipment, look for dust controls. Always use the dust control system and keep it well maintained. Do not use equipment if the dust control system is not working properly.Establish a documented maintenance program for the  dust control systems mentioned below. Dry systems require careful maintenance of the drill deck shroud. When changing filters, the use of respirators by work-ers may be appropriate.Take safety precautions to minimize the presence of  workers near rock drilling. Also, use warning signs and barriers to separate workers, pedestrians, and vehicles from rock drilling equipment.Provide training to rock drillers and assistants in the  use of controls and work procedures.During rock drilling, perform air monitoring of respi- rable crystalline silica exposures to make sure engi-neering controls are working and to determine wheth-er workers need respiratory protection.Engineering ControlsWet drilling systems pump water through the drill  stem to prevent dust from being released into the air. The drill operator controls the flow using a con-trol valve. Some drills are equipped with a flow meter. Raising the water flow will improve dust capture, but too much water will cause operational problems [Or-ganiscak et al. 2003].  Dry dust control system working correctly.Figure 2. Dry collection systems require an enclosure around  the area where the drill stem enters the ground. The enclosure is made by hanging a rubber or cloth shroud from the underside of the drill deck. The enclosure is ducted to a dust collector that has a fan outside of the filter opposite the drill hole. The fan creates neg-ative pressure inside the enclosure capturing dust as it leaves the hole during drilling. The dust is removed in the collector [Organiscak et al. 2003].  When feasible, use rock drilling equipment with en- closed positive-pressure cabs with air conditioning and filtered air supply to isolate the operator from the dust. Older cabs can be retrofitted with systems that filter, heat, and cool the air.Personal Hygiene, Protective Clothing, and Work PracticesWash hands and face before eating, drinking, or smoking.  Do not eat, drink, or use tobacco products in the work area where construction activities are being performed.Change into disposable or washable work clothes at  the worksite. If possible, shower and change into clean clothes before leaving the worksite to avoid contam-inating cars, homes, and other work areas. If it is not possible to shower or change into clean clothes, use a vacuum with a high-efficiency filter to remove dust from clothes. An effective method to remove dust from clothing involves a booth under negative pres-sure that uses an air spray manifold to blow dust from clothing [Pollock et al. 2006]. Do not use a com-pressed air hose to remove dust from clothing.Park cars where they will not be contaminated with  silica dust.Remove dust from equipment using a water hose rather  than compressed air.  Respiratory ProtectionUse respiratory protection when needed. The controls  cited in this report may greatly reduce worker expo-sure to dust; however, respirators may still be neces-sary to reduce exposure to crystalline silica below the NIOSH REL of 50µg/m3.  Follow the Occupational Safety and Health Administra- tion (OSHA) Respiratory Protection Standard (29 CFR* *Code of Federal Regulations. See CFR in References.1910.134) www.osha.gov/SLTC/etools/respiratory/ index.html). The provisions of the program include procedures for selection, medical evaluation, fit test-ing, training, use and care of respirators.   AcknowledgmentsThe principal contributors to this publication were John Organiscak, Andrew Cecala, and Steven Page of the Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health.  John Whalen under a contract with the U.S. Public Health Service, Division of Federal Occupational Health served as writer/editor. ReferencesCFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Reg-ister.NIOSH [1992]. NIOSH Alert: Preventing silicosis and death in rock drillers. Cincinnati, OH: U.S. Depart-ment of Helath and Human Services, Centers for Dis-ease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 1992–107.NIOSH [1996]. NIOSH Alert: Preventing silicosis and deaths in construction workers. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 1996–112. NIOSH [2002]. NIOSH Hazard Review: Health effects of occupational exposure to respirable crystalline sil-ica. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Pre-vention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2002–129. Organiscak JA, Page SJ, Cecala AB, Kissell FN [2003]. Surface mine dust control. In: Kissell FN, ed. Hand-book of Dust Control in Mining. Pittsburgh, PA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Information Cir-cular 9465, pp 73–82.Pollock DE, Cecala AB, Zimmer JA, O’Brien AD, How-ell JL [2006]. A new method to clean dust from soiled work clothes. In: Mutmansky JM, Ramani RV eds. Pro-ceedings of the 11th U.S./North American Mine Ventila-tion Symposium (University Park, PA, June 5–7, 2006). London: Taylor & Francis Group, pp. 197–201.DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention National Institute for Occupational Safety and Health 4676 Columbia Parkway Cincinnati, OH 45226–1998Official Business Penalty for Private Use $300For More InformationThe information in this document is based on NIOSH field studies.  More information about silica hazards and controls is available on the NIOSH Web site at http://www.cdc.gov/niosh/topics/silica/default.html. To receive copies of the NIOSH field study reports that formed the basis of this document or to obtain information about other occupational safety and health topics, contact NIOSH at Telephone: 1–800–CDC–INFO (1–800–232–4636) TTY: 1–888–232–6348  E-mail: cdcinfo@cdc.gov  or visit the NIOSH Web site at www.cdc.gov/nioshFor a monthly update on news at NIOSH, subscribe to NIOSH eNews by visiting http://www.cdc.gov/niosh/eNews.Mention of any company or product does not constitute en-dorsement by NIOSH. In addition, citations to Web sites ex-ternal to NIOSH do not constitute NIOSH endorsement of the sponsoring organizations or their programs or products. Furthermore, NIOSH is not responsible for the content of these Web sites.This document is in the public domain and may be freely copied or reprinted. NIOSH encourages all readers of the Workplace Solutions to make them available to all interested employers and workers.As part of the Centers for Disease Control and Prevention, NIOSH is the Federal agency responsible for conducting re-search and making recommendations to prevent work-related illness and injuries. All Workplace Solutions are based on re-search studies that show how worker exposures to hazardous agents or activities can be significantly reduced.Reducing Hazardous Dust Exposure When Rock Drilling During ConstructionDHHS (NIOSH) Publication No. 2009–124April 2009safer • healthier • peopletm

Reducing hazardous dust exposure when rock drilling during construction

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Reducing hazardous dust exposure when rock drilling during construction

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