Remediation Technologies Screening Matrix, Version 4.0  
Chapter 4 Excavation, Removal, and Off-Site Disposal
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4-2 Hazard Analysis

Principal unique hazards associated with excavation, removal, and off-site disposal include:

Physical Hazards Chemical Hazards Radiological Hazards Biological Hazards

a. Physical Hazards

(1) Description: During soil excavation, workers may be seriously injured or killed by heavy equipment such as front-end loaders and scrapers. This equipment may also generate excessive noise during operation.

Control: Heavy equipment should be equipped with a backup alarm that alerts workers. When approaching operating equipment, the approach should be made from the front and within view of the operator, preferentially making eye contact. Hearing protection should be worn when working around operating equipment. CONTROL POINT: Construction, Operations, Maintenance

(2) Description: During excavation into soil contaminated with explosive, flammable or combustible materials (e.g. carbon disulfide, hydrogen sulfide, methane, tetraethyl lead), the bucket of a backhoe or cutting blade of a crawler may spark when in contact with rocks, buried metal, or other objects, and ignite a flammable vapor that may be generated in the area. During excavation activities, a backhoe or other piece of earth moving equipment may rupture an underground utility such as electrical or gas lines, causing a fire or explosion.

Control: The location of site utilities should be determined prior to excavation activities. Controls to help prevent the ignition of vapors during excavation include equipping earth moving equipment with a non-sparking bucket or blade, and periodically wetting or foaming the active work area with water or a foam fire suppressant. The addition of foam to control vapors may also create a slip and fall hazard. Workers should not walk on areas to which foam has been applied. Conduct area monitoring when airborne chemical concentrations may exceed greater than 1/10 the Lower Explosive Limit (LEL). CONTROL POINT: Construction, Operations

(3) Description: During excavation activities, a backhoe or other piece of earth moving equipment may rupture an underground electrical utility, causing electrocution.

Control: Underground electrical utilities should be located using electromagnetic surveys, inductance surveys, installation maps and drawings, locating services, interviews with utilities personnel, and hand excavation prior to machine excavating. Controls for excavations should adhere to the excavation safety requirements of 29 CFR 1926.650-.652. CONTROL POINT: Design, Construction, Operations

(4) Description: Entry into an excavation may expose workers to confined-space atmospheric dangers and risk of excavated wall collapse. Flooding of an excavation may cause drowning or electrocution if electrical equipment is in use.

Control: A confined-space atmospheric testing program using an oxygen meter, combustible gas meter, and other specific hazardous gas meters should be implemented as part of the confined-space entry program. A confined space is defined as any space with the potential to hold toxic, asphyxiant or explosive concentrations of gas whether more dense (e.g. sump, basement, tank or excavation) or less dense (e.g. low canopy or roofed tank) than air. When confined-space hazards are known or suspected, appropriate health and safety steps include ventilation of the area, entry using supplied air and confined-space techniques, or procedures for eliminating the source of the hazard in the confined space. In basins or impoundments with the potential for rapid flooding, inflation vests should be worn, a process for water lockout should be used, and a rain event procedure developed to extricate workers during rain events. The walls of all excavations greater than 5 feet in depth must either be sloped away from the edge or properly shored in accordance with Occupational Safety and Health Administration (OSHA) guidance (29 CFR 1926.650-652). Confined-space entry procedures must be followed for excavations greater than 4 feet. Regardless of the depth, a competent person must assess the excavation prior to each entry. Workers should not enter an unstable excavation. CONTROL POINT: Design, Construction, Operations

(5) Description: Workers may also be exposed to skin puncture and cut hazards during the excavation and transport of sharp or abrasive objects contained within waste material.

Control: Personal protective equipment, including boots and gloves, should be comprised of puncture-resistant materials. Work boots should be equipped with steel-reinforced shanks to help prevent puncture when walking over waste materials. Materials should be handled with appropriate equipment, not hands or feet, to avoid injury. Materials posing a clear potential hazard (e.g. framing lumber with nails, broken glass) should be carefully removed to avoid later, inadvertent contact. CONTROL POINT: Construction, Operations, Maintenance

(6) Description: Steam pressure washing of equipment may expose workers to thermal or burn hazards, eye hazards due to flying projectiles dislodged during pressure 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 wearing safety goggles and hearing protection during pressure washing activities. Slip hazards may be controlled by workers wearing slip-resistant boots, and by draining water away from decontamination operations into a tank or pit. Walking surfaces should also be drained and kept free of standing liquids and mud. CONTROL POINT: Construction, Operations

(7) Description: Operating heavy equipment over unstable ground (ground that has been affected by pumping or involved in subsurface treatments) may cause the ground surface to subside or sink. The result may cause an injury to the operator of the equipment or to nearby workers.

Control: Where unstable soil conditions may exist, the soil should be accessed by a qualified engineer to ensure safe site operating conditions. CONTROL POINT: Design

(8) 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 amended water or by the use of respiratory protection, such as a air-purifying respirator equipped with a HEPA filter/cartridge. CONTROL POINT: Construction, Operations

(9) Description: During site activities, workers may be exposed to direct and indirect sunlight and the corresponding ultraviolet (UV) radiation. Even short-term exposure to sunlight can cause burns and dermal damage. Exposure to hot and humid conditions may also result in heat stress, which can manifest itself as heat exhaustion and heat stroke.

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, the work and break areas should be shaded. Exposure to heat stress conditions can be minimized by taking frequent breaks, drinking adequate fluids, and performing work during the early morning and late afternoon hours. CONTROL POINT: Construction, Operations

(10) 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. All lifting equipment, such as cranes, forklifts and drilling rigs should remain at least 10 feet from the power line according to OSHA regulations 29 CFR 1926.550 and EM 385-1-1, Section 11.E. CONTROL POINT: Design, Construction, Operations

(11) Description: During the implementation of field activities, equipment and workers may come in close proximity to traffic. Also, drilling rigs and other equipment may need to transit public roads. The general public may be exposed to traffic hazards and the potential for accidents during loading and transporting soil.

Control: Where equipment is to cross roads, warning signs should be used according to the criteria of the Departmentof Transportation Manual on Uniform Traffic Devices for Streets and Highways. A traffic management plan should be developed before remediation activities begin to help prevent accidents involving site trucks and automobiles. EM 385-1-1, Section 21.I.10 provides plan details. CONTROL POINT: Design, Construction, Operations

b. Chemical Hazards

Description: Workers involved with excavation activities may be exposed to VOCs and particulate matter contaminated with semi-volatile organic, and/or inorganic contaminants. Inhalation hazards are particularly evident during warm and dry periods when there is a greater chance for airborne dusts to be generated. The addition of foam to control vapors and/or dust may create a slip hazard. Workers may also be dermally exposed to waste materials during excavation and transport of waste materials. Workers may inadvertently ingest contaminants/waste materials that collect on hands and clothing in the form of dust during excavation. Dust ingestion may also occur when workers take water/meal breaks, or after they have left the work area if established hygiene procedures (e.g. washing hands) are not followed.

Control: Controls may include proper types of personal protective equipment (PPE) and their use, use of experienced workers, repeated health and safety awareness meetings, decontamination stations, and other standard procedures. Examples of PPE include nitrile gloves for dermal exposure to gasoline, an air-purifying respirator equipped with approved filter/cartridges (e.g. HEPA (N100, R100, P100) filters for particulates, organic vapor(OV) cartridges for vapors, or combination filter/cartridges for dual protection), and chemically-resistant disposable coveralls. Dust and other emissions should be suppressed using water or foam suppressants if needed. Workers should not walk on areas to which foam has been applied. Soils should be tested for reactive, highly flammable, or corrosive materials. In extreme conditions (e.g. carbon disulfide) non-sparking tools and intrinsically safe equipment may be required if emissions are expected to be high. CONTROL POINT: Construction, Operations

c. Radiological Hazards

Description: Naturally occurring radioactive material (NORM) is found in all soils, groundwater, and surface water. At typical background levels, this radioactive material would pose neither an internal nor an external hazard during excavation, removal, and/or off-site disposal activities. Elevated levels of naturally occurring radioactivity, however, have been found in materials such as sewage sludge, fossil fuels, fertilizers, and evaporation ponds. Excavation, removal, and/or off-site disposal of radioactive material at greater than background concentrations may pose an internal hazard if radioactive particles are inhaled or ingested. An external hazard may also exist depending upon the type and extent of contamination.

Small particles of uranium metal and some uranium alloys are pyrophoric. They can ignite spontaneously in air as a function of surface to volume ratio. They burn rapidly at very high temperatures.

Certain devices containing radioactive material may also be present in the soils and/or rubbish to be excavated and handled. The likelihood of this can usually be ascertained via site history. U.S. Army and U.S. Air Force gauges painted with radium-226 are examples of commonly encountered devices. Such Aradium gauges@ were primarily RPM gauges in Jeeps. Less common radium gauges are compasses and radar devices. Intact radium gauges will not yield an unacceptable extremity dose. Broken gauges may present an internal hazard if radium paint chips are inhaled or ingested.

Control: A qualified health physicist should be consulted whenever significant radioactive hazards above background are suspected. Site history should be thoroughly reviewed for evidence of concentrated NORM or for the presence of devices containing radioactive material. External hazards from ionizing radiation can be controlled through the use of time, distance, and shielding. Protective clothing can be used to prevent external contamination. Internal hazards can be controlled by the use of respiratory protection (e.g. HEPA(N100, R100, P100) filter/cartridge) and engineering controls. Decontamination procedures/facilities may be necessary to reduce radiation exposure. Dust and other emissions should be suppressed as described above for chemical hazards. CONTROL POINT: Design, Construction, Operations

d. Biological Hazards

(1) Description: Microorganisms in the groundwater and soil may pose exposure hazards at sites containing medical wastes or sewage sludge. Workers may be exposed to inhalation/ingestion and/or dermal contact with pathogens such as Coccidioides sp., Histoplasma sp., and Mycobacterium sp.

Control: The microorganisms present in the groundwater and soil may be known or tested, and the appropriate PPE used to prevent exposure. The appropriate PPE may include an air-purifying respirator equipped with HEPA(N100, R100, P100) filters. Most rubber gloves (e.g. nitrile or PVC) provide protection against microorganisms; however, the type of glove used must also be compatible with contaminants at the site. The use of latex gloves may aggravate or cause allergic reactions in some people. Dust suppression with water or amended water sprays can help. Eating, drinking, and smoking restrictions prior to washing/decontamination should also be strictly enforced. Decontamination with water and or disinfectant soaps may be used to control exposure. Chemically-resistant protective overalls should be worn to prevent clothes from becoming grossly contaminated with wastes, soils, and/or contaminated water which may contain potentially hazardous microbes. If contaminated clothing is to be laundered, it should be performed by a commercial laundry familiar with cleaning procedures for industrial clothing. These procedures include employee hazard warnings and cleaning solution disposal requirements. CONTROL POINT: Design, Construction, Operations

(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. Exposure to deer ticks may cause Lyme disease.

Control: Periodic inspections of the site should be performed to identify stinging insect 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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