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Remediation Technologies Screening Matrix, Version 4.0  
Chapter 2 Landfill Covers and Liners
Table of Contents



2-2 Hazard Analysis

Principal unique hazards associated with landfill covers and liners include:

Physical Hazards Chemical Hazards Radiological Hazards Biological Hazards

a. Physical Hazards

(1) Description: Landfill covers/liners installed during periods of high winds may pose trip hazards and/or throw or knock down workers holding or standing on or near unsecured liners.

Control: Controls for wind hazards include selecting an appropriate liner material, installing liners on calm days, and placing soil or sand bags onto the unrolled portion of the liner. The new installer should determine the temporary anchoring needs at the time of installation and ensure that specifications for anchoring are met or exceeded. CONTROL POINT: Design, Construction, Operations, Maintenance

(2) Description: Geomembrane and wet clay liners can be very slippery, and when placed on the slopes or used for footing while a worker carries equipment or materials, can present significant slip hazards.

Control: Controls for slip hazards should be considered during design (see EM 385-1-1, Section 21.A). Additional controls may include using rope ladders for ascending/descending lined slopes, selecting appropriate shoe soles for maximum traction, laying high-traction walkways over the liners, carrying light loads, or using more workers to carry larger single loads. CONTROL POINT: Design, Construction, Operations, Maintenance

(3) Description: Synthetic liners are made in varying thicknesses and rigidities. Some liner edges are sharp and stiff after cutting to shape, and can inflict cuts and abrasions.

Control: Controls include wearing long-sleeve shirts, full-length pants, and appropriate work gloves (e.g. leather or leather-palmed) for better grip and protection. Safety glasses or goggles should also be worn to help prevent eye injuries. CONTROL POINT: Construction, Operations, Maintenance

(4) Description: Most synthetic cover/liner materials are dark or black colored to enhance ultraviolet (UV) resistance, and thus absorb radiant energy and emit considerable heat. The surfaces of cover/liner materials can also reflect considerable angled radiant energy, amplifying the energy absorbed by the worker even when wearing a hat. Heat stress, including heat exhaustion and heat stroke, may effect workers during operations. Hot and humid conditions, combined with operations, such as liner welding or other heat-producing activities, may also increase the potential for a heat-related illness.

Control: Controls include wearing hats and wick clothing, providing water to replace body fluid, taking frequent breaks to ingest, prohibiting alcoholic beverages, providing ventilation, canopies and/or shaded break areas. Additional measures include working nights, working early and late in the day, scheduling jobs for cooler times of the year. CONTROL POINT: Design, Construction, Operations

(5) Description: Manual lifting and moving of heavy materials used for anchoring may expose workers to muscle strain/sprain to the lower back and/or shoulder.

Control: Mechanical lifting equipment, such as cranes, backhoes with cables, and spreaders should be used to lift, move, and unfold or unroll liner material to help avoid worker muscle injuries. CONTROL POINT: Construction, Operations

(6) Description: Equipment, including "hot-shoe" welders and extrusion welders, can expose workers to burn hazards. Flare systems for the discharge of off gas from the landfill and generators may also pose burn hazards.

Control: All personnel using welding equipment should be trained and experienced in the proper use of hot-shoe welding equipment. Those using or exposed to hot operating equipment should be informed at the start of the project, and reminded during daily health and safety meetings about the hazards posed by the equipment. All exposed heated surfaces should be guarded when practical to prevent accidental contact. Procedures for the safe operation, repair, and maintenance of this equipment should be requested from the manufacturer and/or installer, and included in health and safety and installation work plans. The use of insulated gloves with gauntlets, coveralls, and face protection may be warranted. CONTROL POINT: Construction, Operations

(7) Description: Fire and explosion hazards may exist if the off-gas flare systems are improperly designed, maintained, or installed. Also, volatile organic compounds (VOCs) may be generated as off-gas products from wastes in the landfill and accumulate. These gases are explosive and may be ignited as off-gas products by sparks, open flame, or heated surfaces.

Control: The landfill designer should ensure that the accumulation of off gases is prevented by a properly designed and installed off-gas management system. The system should be designed using the guidance provided in the EPA Document: EPA/625/4-89/022, Requirements of Hazardous Waste Landfill Design, Construction and Closure. Gas collection and vent systems should be installed into the cover. Unless properly vented, the lateral migration of gas should be anticipated. CONTROL POINT: Design, Construction, Operations, Maintenance

(8) Description: Off-gas drive engines may generate carbon monoxide and carbon dioxide during operation. Also, VOCs generated as off-gas products by landfill wastes may accumulate. If the gases are not properly vented, they may accumulate to hazardous levels in areas such as buildings and sheds. Exposure to elevated levels of these gases may cause headaches, dizziness, and nausea, or possibly even death.

Control: The landfill designer should specify the ventilation/flaring requirements necessary to ensure adequate venting of off gases from beneath landfill covers and prevent the potential accumulation of gases migrating into nearby buildings or other structures on or off site. Buildings or other enclosed-space facilities should be properly ventilated and tested to prevent accumulations of carbon monoxide, carbon dioxide, methane, hydrogen sulfide and other dangerous gases. CONTROL POINT: Design, Construction, Operations, Maintenance

(9) Description: Electric shock hazards may exist from on-site generators/infrastructure. Generators may be present during construction, operations (off-gas dependent generation), or maintenance.

Control: Verify that the hazardous area classifications, as defined in National Fire Protection Association (NFPA) 70-500-1 through 500-10, are indicated on the drawings. All controls, wiring and equipment, including the on-site generators/infrastructure, should be in conformance with the requirements of EM 385-1-1, Section 11.G and NFPA 70 for the identified hazard areas. Equipment should be grounded and/or provided with ground fault interrupter circuit (GFIC) protection if required by EM 385-1-1, Section 11 or NFPA 70 requirements. Only trained and experienced workers should be permitted to work on the systems. Appropriate lockout/tagout procedures should be included in the construction and O&M of the system. Fire extinguishers rated for energized electrical systems should be readily available where electrical equipment is installed and operated. CONTROL POINT: Design, Construction, Operations, Maintenance

(10) Description: Heavy equipment and portable electric generators may create noise hazards to operators or workers in the immediate vicinity. The generators may also pose an electrocution hazard.

Control: Hearing protection should be worn by workers exposed to noise at or above 85 decibels (steady-state), or to impulse noise of 140 decibels such as that generated by heavy construction equipment or generators. CONTROL POINT: Construction, Operations, Maintenance

(11) Description: Any equipment (small and large) used to move soil and liner materials on steep slopes may roll over, crushing the operator.

Control: The angle of the slope should be designed to minimize the potential for roll-over. The construction contractor must maintain safe slopes during construction. Heavy equipment should be equipped with roll-over protective devices (ROPS), and operators should not operate equipment on excessively steep slopes. Seat belts should be worn during operation. CONTROL POINT: Design, Construction, Operations

(12) Description: During placement of cover soils over geosynthetics, small, lighter earth-moving equipment may be used in performing construction operations because the lighter weight may minimize damage to the existing cover. However, if this lighter equipment is operated on steep slopes, there may be increased risk of the equipment rolling over. During construction, heavy vehicular traffic may also pose a danger to site workers. The movement of heavy equipment in high traffic areas or public roads may further pose a danger to site workers or to the public.

Control: Haul road considerations should be addressed in the design stage (see EM 385-1-1, Section 21.I for control measures). Where equipment must cross over active roads, warning devices should be used according to the criteria of the Department of Transportation Manual on Uniform Traffic Devices for Streets and Highways. Equipment should have roll-over protective devices (ROPS), and should not be operated on excessively steep slopes. CONTROL POINT: Design, Construction, Operations, Maintenance

(13) Description: During installation of the liner, trenches may be excavated to secure the liner edges. Open excavations may pose a trip hazard to workers crossing the excavation, or a collapse hazard to workers working near trench edges.

Control: Protection shall be provided to prevent personnel, vehicles, and equipment from falling into excavations. All workers should be informed of on-site hazards and allowable access to the landfill. See EM 385-1-1, Section 25.B for additional control measures and requirements. CONTROL POINT: Construction, Operations, Maintenance

(14) Description: Workers may be seriously injured or killed during operation by heavy equipment moving liners and other materials. As liners are unrolled, workers may be exposed to these same hazards if the liner is allowed to unroll down a working slope of a landfill.

Control: Earth-moving equipment and trucks should be equipped with a backup alarm that alerts workers. When approaching operating equipment, the approach should be made from the front and always within view of the operator. An alarm communication system should be developed to warn workers during liner unrolling activities, as necessary. CONTROL POINT: Construction, Operations, Maintenance

(15) Description: Steam-pressure washing of equipment may expose workers to thermal or burn hazards, eye hazards from flying projectiles dislodged during washing, slip hazards from wet surfaces, and noise hazards.

Control: Thermal burns may be prevented by using insulated gloves (e.g. silica fabric gloves). Eye injuries and hearing loss may be prevented by using safety goggles and hearing protection. Slip hazards may be controlled by wearing slip-resistant boots, and draining water away from decontamination operations into a tank or pit. Walking surfaces should be drained and free of standing liquids or mud. CONTROL POINT: Construction, Operations, Maintenance

(16) Description: Depending on soil types, exposure to respirable quartz may be a hazard. Consult geology staff to confirm the presence of a respirable quartz hazard (e.g. to determine if soil types are likely to be rich in respirable quartz). As an aid in determining respirable quartz exposure potential, sample and analyze site soils for fines content by ASTM D422, followed by analysis of the fines by X-Ray Diffraction to determine fine material quartz content.

Control: Worker exposure to dust rich in respirable quartz may be minimized by periodically wetting the soil with water or by using respiratory protection, such as an air purifying respirator equipped with a HEPA filter/cartridge. Wetting of soil may require additional controls to deal with resulting water, ice, mud, etc. CONTROL POINT: Design, Construction, Operations, Maintenance

(17) Description: During site activities, workers may be exposed to direct and indirect sunlight and the corresponding UV radiation. Even short-term exposure to sunlight can cause burns and dermal damage.

Control: Exposure to direct and indirect sunlight should be minimized where possible in the summer months. Workers can minimize direct sun exposure by wearing long-sleeve shirts and full-length pants, and by applying UV barrier sunscreen. If possible, work and break areas should be shaded. CONTROL POINT: Construction, Operations

(18) Description: Predesign field activities associated with landfill construction include surveying, biological surveys, soil gas surveys, geophysical surveys, methane gas assessments, trenching, drilling, and other activities. Each of these field activities may expose the survey personnel to physical, chemical and biological hazards.

Control: An activity hazard analysis should be prepared for predesign field survey activities. EM 385-1-1, Section 1.A provides guidance on developing an activity hazard analysis. CONTROL POINT: Design, Construction, Operations

(19) Description: The general public may be exposed to traffic hazards and the potential for accidents during loading and transporting soil from borrow pits to the landfill.

Control: A traffic management plan should be developed before excavation activities commence to help prevent accidents involving dump trucks and automobiles. EM 385-1-1, Section 21.I10 provides plan details. CONTROL POINT: Design, Construction, Operations

(20) Description: Workers may be exposed to electrocution hazards when working around electrical utilities such as overhead power lines.

Control: The location of overhead power lines, either existing or proposed, should be noted in the pre-design phase. According to Occupational Safety and Health Administration (OSHA) regulation 29 CFR 1926.550 and EM 385-1-1, Section 11.E, all lifting equipment, such as cranes, forklifts and drilling rigs, should remain at least 10 feet from a power line. CONTROL POINT: Design, Construction, Operations

(21) Description: During excavation activities, workers may be exposed to explosion hazards associated with unexploded ordnance or buried flammable materials at military bases.

Control: Prior to excavation, metal detectors or ground penetrating radar should be used to clear the excavation area of such hazards. Hand probes may also be used. Excavation into soil suspected of containing an underground hazard should proceed slowly and with caution. CONTROL POINT: Design, Construction, Operations

b. Chemical Hazards

(1) Description: The heating or solvent welding of the cover/liner materials may generate vapors from adhesives, thermal decomposition and/or outgassing of liner material components such as plasticizers (e.g. phthalate esters, adipate esters), or from any solvents contained in the adhesive (e.g. methyl ethyl ketone, methylene chloride). A dermal hazard may also exist from skin contact with the cementing chemicals and/or waste materials generated during installation.

Control: During installation, workers may need to ventilate the area or use appropriate respirators to control exposures. Respirator cartridges should be selected based on consultations with the liner manufacturer(s), and the potential compounds which may be emitted. Use of personal protective equipment (e.g. chemically-resistant gloves such as nitrile) may be used to help control dermal exposure. An analysis of possible chemical exposures should be performed prior to issuing gloves and other personal protective equipment. The analysis should include obtaining specific chemical hazard information on the liner constituents, and/or constituents used in the cementing agents to ensure that the personal protective equipment (PPE) specified will be appropriate for respective chemical hazards. CONTROL POINT: Construction, Operations, Maintenance

(2) Description: Workers may be exposed to waste chemicals such as airborne dusts and particulates, and VOC emissions resulting from redistribution of wastes associated with liner installation, landfill off gassing, and/or leachate collected by leachate collection and treatment systems. Leachate may contain both organic and inorganic constituents.

Control: Workers may apply water or an amended water solution to help control the generation of airborne dusts, particulates and VOCs. Workers may also use respiratory protection including air-purifying respirators equipped with approved filters/cartridges (HEPA filters for particulates, OV cartridges for vapors, or combination filter/cartridges for dual protection). Exposure to leachate may be controlled by the use of PPE. An analysis of the work tasks and potential chemical exposure should be performed to determine the correct PPE and/or respirator cartridge(s) if needed. All analyses should include a chemical waste profile on wastes to help ensure that the PPE specified will be appropriate for the respective chemical hazard(s). CONTROL POINT: Construction, Operations, Maintenance

(3) Description: Methane generated by existing landfills is highly combustible and is an asphyxiant. The off gas generated from an existing landfill may also contain substantial concentrations of vinyl chloride and hydrogen sulfide. Vinyl chloride is a human carcinogen and hydrogen sulfide damages lungs and circulation. The hazards from exposure to landfill gas must be considered during predesign, design, construction and O&M phases.

Control: During the pre-design phase, soil gas surveys should be performed to determine the level of methane, hydrogen sulfide, and vinyl chloride in soil. There are three methods for collecting landfill off-gas samples during soil gas surveys: barhole probe, permanent gas monitoring probes, and gas extraction wells. These three methods are discussed in detail in the EPA document EPA-450/3-90-011a, Air Emissions from Municipal Solid Waste Landfills. During the construction phase, periodic monitoring of landfill off gas should be performed, especially in enclosed areas such as excavations and other low, undisturbed areas. Where levels reach 10% of the lower explosive limit (LEL), the area must be allowed to ventilate until methane levels are below 10% of the LEL. CONTROL POINT: Design, Construction, Operations

c. Radiological Hazards

(1) Description: Use of a nuclear gauge to determine the moisture content and density of the clay liner and cover may pose a radiation hazard.

Control: Controls include the use of personnel with the proper training and experience in the use and maintenance of the neutron density gauge. Use of the gauge must comply with the Nuclear Regulatory Commission (NRC) Standards for Protection Against Radiation (10 CFR 20), NRC Rules of General Applicability to Domestic Licensing of Byproduct Material (10 CFR 30), licensing requirements for the particular source (10 CFR 31,32, or 39), all license conditions, and OSHA 29 CFR 1910.1096 or 29 CFR 1926.53. CONTROL POINT: Construction, Maintenance

(2) Description: Although an uncommon hazard, radioactive materials placed into the landfill (purposely or inadvertently) may pose a radiation hazard by exposure to radiation or inhalation/ingestion of radioactive particles during the installation of covers/liners. A variety of radiation sources may have ended up in landfills including Naturally Occurring Radioactive Materials (NORM) from oil and gas exploration and production, medical wastes, low-level research wastes, and disposed instruments and their sources. Some radioactive materials are pyrophoric. Machine filings or turnings of uranium or thorium may spontaneously ignite, and pose fire and airborne radioactivity hazards. Turnings or filings buried in existing landfills may combust upon excavation when the material is exposed to air. Other radioactive materials may present an external exposure hazard.

Control: The contents of the landfill should be known or tested prior to the initiation of construction or maintenance operations. If any radioactive material is found, a qualified health physicist should be consulted to determine the exposure potential and any necessary engineered controls or PPE. If present, the nature and extent of the radiation and/or radioactive materials should be determined, and the appropriate PPE used to prevent exposure. Decontamination facilities should be provided using guidance such as The Health Physics and Radiological Health Handbook (Benard, Schleien, Scinta, Inc. 1992). CONTROL POINT: Design, Construction, Operations, Maintenance

d. Biological Hazards

(1) Description: At those sites involving medical wastes or sewage sludge, biological hazards may result through inhalation/ingestion and/or dermal contact with microbes in the waste and pathogens, such as Coccidioides sp., Histoplasma sp., and Mycobacterium sp. Exposure to biological hazards may result in eye and skin bacterial and fungal infections.

Control: The contents of the landfill should be known or tested to assess the potential risk, and prevent exposure to dangerous biological materials during construction. If present, the nature and extent of biological materials should be determined, and the appropriate PPE used to prevent exposure and provide decontamination. Dust suppression techniques using water or amended water treatments should be used to help prevent inhalation/ingestion of biological materials. Dust suppression techniques may be employed when adequate runoff controls are in place, and a slip hazard is not generated from the wetting of the material. To help control eye infections, portable eye washes may be used to remove dust or other objects which enter the eyes. Prior to eating or drinking, the hands and face should be washed with germicidal soap. CONTROL POINT: Design, Construction

(2) Description: Workers may be exposed to a wide array of biological hazards, including snakes, bees, wasps, ticks, hornets, and rodents during any phase of remediation. The symptoms of exposure vary from mild irritation to anaphylactic shock and death. Deer ticks may cause Lyme disease.

Control: Periodic inspections of the site should be performed to identify bee hives and wasp nests, and for the presence of snakes. Professional exterminating companies should be consulted for removal. Tick and insect repellents may be used for exposure control. However, workers should check their skin and clothing for ticks periodically throughout the work day. CONTROL POINT: Construction, Operations, Maintenance

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