3-2 Hazard Analysis

Principal unique hazards associated with extraction/monitoring wells (vertical/horizontal wells),(soil flushing) include:

a. Physical Hazards

(1) Description: During drilling operations, heavy equipment such as augers, cables, buckets, and pipes are periodically raised overhead and placed into or above the well. Thus, workers may be exposed to swinging equipment during lifting, or may be exposed to crushing hazards if equipment falls or is carelessly lowered. Loose clothing may become entangled in cables used to raise and lower equipment or on the equipment. Lowered augers, buckets, or direct push drilling methods (using hydraulic pressure to advance a soil boring) may further pose a crushing hazard to hands and/or feet. Rough edges or spaces on cables, auger flights, buckets, and pipe may cause cuts and abrasions.

Control: A work zone should be established around the drilling rig and only those personnel and equipment required for the task should be permitted within the zone. Lifting equipment should be inspected regularly and operated safely. Equipment should be raised only as high as needed. Contact should be maintained with the raised equipment to help minimize swinging of the equipment. Site workers should wear appropriate clothing and equipment. Operators should avoid contact with auger edges, running cables, and pipe, and should wear work gloves to prevent cuts and abrasions from exposed spurs, wires, and edges. No jewelry should be worn. CONTROL POINT: Construction, Maintenance

3-3 Soil Flushing

(2) Description: The rotating auger and other rotating or moving parts, such as "cat heads" and winches, pose a potential hazard to workers if loose clothing becomes entangled with the revolving equipment.

Control: Controls include securing all loose clothing, removing jewelry, using low-profile auger pins, and using long-handled shovels to remove soil cuttings from the borehole. Cable systems should be used with caution and inspected regularly for loose strands or frayed wires that may become entangled in loose clothing. A "cut-off" switch, accessible to all drill crew members, should be standard on all drilling equipment used. Operators should be trained on the safe practices associated with drilling operations. CONTROL POINT: Construction, Maintenance

(3) Description: Fire, explosion and/or electrocution hazards may exist when using hollow-stemmed auger, direct push, or other drilling methods if the drilling mast or auger comes in contact with overhead electric lines, or ruptures underground utilities or tank/piping systems.

Control: Identify the location of all below- and above-ground utilities prior to drilling. Contact local utilities and public works personnel to determine the locations of utilities. Use a metal detector to help detect buried metal piping. When there is any doubt or uncertainty, probe with a metal rod prior to excavation or hand excavate to determine the exact location of utilities prior to drilling. Once utilities are located, careful excavation by backhoe may be allowed. When raising a drill mast, always have an observer to the side to observe and guide. Operate the mast at its lowest height; different drill rigs will have different mast elevations and may be operated at different heights. Do not move the drilling rig with the mast raised. During design, locate overhead hazards and design so that installations using erect equipment are not necessary in that area, if possible. CONTROL POINT: Design, Construction

(4) Description: Soil boring using hollow-stemmed augers, or other drilling methods may cause a fire or explosion in soils saturated with flammable or combustible materials. Sparks generated when an auger contacts rocks, metal, or other underground objects may ignite a flammable atmosphere inside the bore hole. Examples of materials particularly subject to ignition in this manner are carbon disulfide (CS₂), methane, "natural gas," ethane, propane, ethylene, and benzene. Hydrogen sulfide, a decomposition product, is an axphyxiant. This hazard would not be considered an ordinary hazard at sites.

Control: If drilling activities are expected to take place in areas known or suspected to contain soils saturated with flammable or combustible materials, use methods such as mud or water rotary drilling (rather than hollow-stem augers) which add moisture to the cutting area. CONTROL POINT: Design, Construction

(5) Description: Electricity in a wet environment, and in the presence of flammable, floating layers of explosive NAPL, may cause a fire or explosion.

Control: Verify that the hazardous area classifications, as defined in NFPA 70-500-1 through 500-10, are indicated on the drawings. All controls, wiring and equipment 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 equipment and 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

(6) Description: Extraction of flammable liquids may cause a fire if the material is ignited via extraction, transfer or storage, or if gases vented from the storage tank come in contact with a spark or other source of ignition. Fires may also occur if extraction pumps are not selected and installed in accordance with the appropriate EM 385-1-1, Section 11 and NFPA 70 requirements.

Control: 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. Tank vents should be directed to prevent contact with sources of ignition. Verify that the hazardous area classifications, as defined in NFPA 70-500-1 through 500-10, are indicated on the drawings. All controls, wiring and equipment, including the piping system, should be in conformance with the requirements of EM 385-1-1, Section 11.G and NFPA 70 for the identified hazard areas. Only trained and experienced workers should be permitted to work on the systems. Appropriate lockout/tagout equipment and 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

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

(8) Description: Drill rigs can seriously injure workers while being positioned for drilling.

Control: Drill rigs and other vehicles should be equipped with a backup alarm that alerts workers to moving vehicles. When approaching operating equipment, the approach should be made from the front and within view of the operator, preferentially making eye contact. CONTROL POINT: Construction, Maintenance

(9) Description: During site activities, workers may be exposed to direct and indirect sunlight, and corresponding ultraviolet (UV) radiation. Even short-term exposure to sunlight can cause burns and other 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: Manual lifting of heavy objects may expose workers to back, arm and shoulder injuries.

Control: Workers should not be required to lift heavy loads manually. Some loads may require two people. Proper lifting techniques include stretching, bending at the knees, and bringing the load close to the body prior to lifting (see EM 385 1-1, Section 14.A). Mechanical lifting equipment, such as forklifts, should be used to lift or to move loads. CONTROL POINT: Design, Construction, Operations, Maintenance

b. Chemical Hazards

(1) Description: Exposure to airborne dusts, volatile organic compounds (VOCs), and metals in contaminated soils and/or groundwater brought to the surface during drilling, soil and groundwater sampling, and infiltration system installation can be hazardous to on-site personnel. During well installation, site workers may be exposed to gasoline, diesel fuel, or other organic materials as well as heavy metals such as lead and chromium. These hazards can be contacted through dermal exposure, ingestion, or vapor inhalation. Workers may also be exposed to reactive, caustic, or acidic materials from cuttings and groundwater.

Control: Controls include the proper use of personal protective equipment (PPE) selected by a qualified health and safety professional (e.g. air-purifying respirators, chemically-resistant disposable coveralls, water/chemical impervious gloves [e.g. nitrile], and rubber or steel-toed leather boots), frequent health and safety meetings, use of experienced workers, decontamination stations, and/or other standard procedures. Soils should be tested for reactive, highly flammable, or corrosive materials. All installation methods should be designed appropriately. In extreme conditions (e.g. carbon dioxide), non-sparking tools and intrinsically safe equipment may be required if emissions are expected to be high. Personnel and general area monitoring for airborne chemicals should be conducted when exposures may potentially exceed 2 of the threshold limit value (TLV) or permissible exposure limit (PEL). Use proper respiratory protection(e.g. air-purifying respirator with filters and/or organic vapor cartridge) if ventilation or other engineering, work practice, or administrative controls are insufficient to maintain exposures less than the TLV or PEL. Select respiratory protective equipment in accordance with the OSHA regulation 29 CFR 1910.134 and the National Institute for Occupational Safety and Health (NIOSH) guidelines. Conduct area monitoring when airborne chemical concentrations may exceed greater that 1/10 the lower explosive limit (LEL). CONTROL POINT: Construction, Maintenance

(2) Description: Exposure to contaminants may be enhanced by the use of additives (usually surfactants used in flushing), which may increase dermal absorption and may hold the contaminants on the skin. For example, linear alkyl benzene sulfonate or ethoxylate surfactants could be used to enhance recovery of contaminants as part of a pump-and-treat groundwater extraction program. This could also enhance concentrations of contaminants in the recovered water, increasing the risk and hazard of contact with that water. In addition, additives can increase the solubility of contaminants, raising concentrations to which personnel are exposed.

Control: The system designer should select additives with the lowest health and safety impact which can still perform the process (e.g. avoid use of materials such as dimethyl sulfoxide [DMSO], which enhances dermal absorption when other solvents are available and practical). CONTROL POINT: Design, Operations

(3) Description: Fire and/or explosion or chemical release (inhalation/ingestion/asphyxiation) hazards may exist when using hollow-stem auger, direct push, or other drilling methods if drilling ruptures underground utilities, or tanks/overhead piping systems which contain hazardous chemicals.

Control: Perform a utility survey, probe with a metal rod prior to excavation, or hand excavate to determine the exact location of underground lines prior to drilling. During design, develop actions/procedures to locate overhead hazards, and minimize installations using erect equipment which are not necessary in that area, if possible. CONTROL POINT: Construction

(4) Description: Acids used in well flushing or rehabilitation may pose skin, eye, or inhalation hazards upon contact.

Control: Closed acid injection systems should be used to minimize worker exposure to acids. Workers should also wear personal protective equipment, such as neoprene gloves, chemically-resistant coveralls, safety goggles and a face shield. CONTROL POINT: Design, operations, maintenance

c. Radiological Hazards

(1) Description: Use of a neutron or gamma source in down-hole logging systems to log wells may pose a radiation hazard if improperly used, or if damaged in such a way as to expose the sources.

Control: Controls include the use of personnel with the proper training and experience in the use of neutron density gauges, proper maintenance of the instrument, and compliance 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), and the appropriate part of 10 CFR pertaining to the type of license required for the particular source (10 CFR 31,32, or 39), as well as license conditions and OSHA 1910.1096 or 29 CFR 1926.53 criteria. CONTROL POINT: Design, Construction, Maintenance

(2) Description: Contaminants in the groundwater and soil may pose a rare radiation hazard to personnel through inhalation or ingestion of radioactive materials during installation, sampling, and maintenance of wells or well-related systems. Buildup of radioactive scale in the well and associated piping may present an external exposure hazard. Contaminants may include naturally occurring radioactive material (NORM), radium, thorium, and uranium, or radioactive wastes that have been buried in previous disposal activities.

Control: The presence of radioactive materials may be known, or the soil and groundwater may be tested to determine if elevated levels of radioactive materials are present. If any radioactive material above background levels is found, a qualified health physicist should be consulted to determine the exposure potential and any necessary engineered controls or PPE. CONTROL POINT: Design, Construction, Maintenance

d. Biological Hazards

(1) Description: At those sites involving medical wastes or sewage sludge, microorganisms in the groundwater and soil may pose exposure hazards during the installation, sampling, and maintenance of the wells or well-related systems. Any microorganisms present in the groundwater and soil may be known or tested. Workers may be exposed to inhalation/ingestion and/or dermal contact with pathogens, such as Coccidioides sp., Histoplasma sp., and Mycobacterium sp. The resulting exposure may result in an occupational illness.

Control: Microorganisms present in the groundwater and soil may be known or tested, and the appropriate PPE used to prevent exposure. The appropriate PPE would typically include an air-purifying respirator equipped with HEPA (N100, R100, P100) filters/cartridges. Eating, drinking, and smoking restrictions prior to washing/decontamination should 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

(2) Description: Well vaults or enclosures may have snakes, spiders, scorpions or other potentially dangerous insects and animals sheltering or trapped in them which could bite or sting workers during operations or maintenance.

Control: Well vaults should be designed with tight covers where practical to prevent entry of insects and animals. Well vault covers may be removed with a hook or other tools to prevent possible bites or stings. Vaults should be inspected after opening and prior to entry to determine if snakes, spiders, scorpions, or other potentially dangerous insects and animals are present. If present, the animals should be removed in a safe manner to be determined by a qualified health and safety professional. CONTROL POINT: Design, Operations, Maintenance

(3) 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