Information for cannabis processors

Only highly trained operators who can demonstrate proficiency and understand safe operating procedures should operate cannabis extraction equipment.

Extraction systems are used to separate cannabinoids from the physical plant material. There are a variety of cannabis extraction methods available to processors, depending on the desired end-product. The most common commercial extraction systems use hydrocarbon solvents such as butane or propane. Other cannabis extraction methods may involve carbon dioxide – for example, supercritical or subcritical CO2 extraction – or ethanol as the extraction agent.

• Oregon OSHA requires that all extraction systems be professional-grade closed-loop systems. Closed-loop extraction systems reduce the risk of explosions because highly flammable extraction solvents are contained within the system during the extraction process.
• Closed-loop extraction systems – including equipment such as pumps, ovens, and evaporators – must be approved by a licensed engineer.
• The extraction room and the equipment, including all electrical installations, must meet the requirements of the Oregon Structural Specialty Code, Oregon Mechanical Specialty Code, and the Oregon Fire Code.
• The extraction room must have an exhaust system that provides a ventilation rate of one cubic foot per square foot of solid floor and use only explosion-proof or intrinsically safe fans. For example, an extraction room with 100 square feet of solid floor space must have an exhaust system that provides a ventilation rate of 100 cubic feet per minute.
• Extraction equipment and facilities must be approved for use by the local fire and building codes. The NFPA 1 fire code (2018), Chapter 38, includes fire safety requirements for cannabis growing, processing, and extraction facilities.
• In most cases, extraction system services such as consultations on extraction system components and extraction system design must be performed by a professional engineer registered with the Oregon State Board of Examiners for Engineering and Land Surveying. (There are some exceptions. See ORS 672.060.)
• A professional engineer must prepare and sign a report that documents how the closed-loop extraction equipment meets applicable Oregon and national safety standards.
• The Oregon Liquor Control Commission requires emergency eye wash stations in any room in which in which cannabinoid extract is processed.
• All applicable safety data sheets must be readily available to personnel in accord with Oregon OSHA's hazard communication requirements.
• Extraction rooms that handle hazardous materials – such as butane and propane – must provide at least one exit door that swings out when a person leaves the room and that self-closes or closes automatically. The door must also have panic and fire exit hardware installed.

Hydrocarbons are a class of chemicals that include butane, propane, and liquefied petroleum gas.

Butane extraction is the most common form of hydrocarbon extraction in the cannabis industry. Butane is popular as an extraction solvent because of its physicochemical properties and its low cost. Propane can be used instead of butane, depending on the extraction method used by the processor and the attributes of the desired end product. Both butane and propane extraction require careful temperature management to avoid the risk of an explosion.

Regardless of the method used, the fundamentals of hydrocarbon extraction are similar, regardless of a processor's approach: a solvent (such as butane) is “run" through raw cannabis to dissolve the desired cannabinoids and other active ingredients from the plant matter to create a liquid resin that can be further refined. Part of that refinement is the removal of residual solvent vapors still present in the resin after the extraction run has finished. Commercial-grade vacuum ovens are a safe and reliable way to remove excess extraction solvent from resin.

Hydrocarbon extraction systems can be used only within in Class 1, Division 1 locations to reduce the risk of fire and explosions and to meet the requirements of the Oregon Electrical Specialty Code. A Class 1 designation means that flammable gases or vapors may be present at the location. A Division 1 designation means that gases exist under normal operating conditions. Because butane and propane readily evaporate and are highly flammable, they must be managed carefully to minimize the risk of a fire or explosion – particularly when they are loaded, unloaded, and stored. It is essential to identify any potential ignition hazards before extraction begins.

Areas where butane or propane are used must have intrinsically safe exhaust ventilation located within 12 inches of the floor that provides a minimum of one cubic foot per minute per square foot of solid floor.

All equipment in the extraction room must also be rated for use in Class 1, Division 1 locations – including any lighting, power receptacles, vacuum pumps, recovery pumps, and any other electrical equipment (including cellphones). To reduce the possibility of a spark from a static discharge, the extraction equipment and all metal objects, including ductwork, hand sinks, and water pipes, must be grounded or bonded in accordance with the Oregon Electrical Specialty Code. Adequate precaution must be taken to prevent the ignition of flammable vapors. Ignition sources include:

• Smoking
• Open flames
• Cutting and welding
• Hot surfaces
• Frictional heat
• Sparks
• Spontaneous ignition from heat-producing tools, radiant heat, and cellphones

A fixed continuous flammable gas detector is required in hydrocarbon extraction rooms. A portable flammable gas detector should be available to ensure flammable oil and plant material are not removed from the extraction room. This calibrated detector will alert workers when conditions inside the extraction room reach or exceed 10 percent of the lower flammable limit (LEL) for the gas. This helps workers identify leaks during the extraction process, as well as when resin and the extracted plant materials can be safety removed from the extraction room.

Ethanol extraction uses ethanol as an extraction solvent to remove cannabinoids instead of hydrocarbons or carbon dioxide. Ethanol extraction is typically conducted under cooled conditions. The ethanol is recycled and used again, typically with free-falling or rotary evaporators. Equipment used for evaporation must be UL-approved for flammable liquids.

Ethanol can also be used to refine extracts produced by other extraction methods.

Ethanol can ignite at normal room temperatures and ethanol's vapors are also heavier than air, which means the vapors tend to accumulate at ground level until dispersed by wind or ventilation. Areas where ethanol is used must have intrinsically safe exhaust ventilation located within 12 inches of the floor that provides a minimum of one cubic foot per minute per square foot of solid floor.

Extraction processes that use large quantities of ethanol (60 gallons or more) require spill control measures such as diking or curbing, or secondary containment to control spills.

Carbon dioxide is typically a gas or the solid dry ice. However, carbon dioxide can also become a supercritical fluid, meaning it converts to a liquid under high pressure (above 1,070 psi) and relatively high temperature (above 87.8 °F (31 °C)). In its supercritical fluid state, carbon dioxide can be used as a solvent to extract cannabinoids. When the solvent is warmed, the carbon dioxide evaporates, leaving behind pure extract.

Unlike hydrocarbon extraction, carbon dioxide extraction does not require a flammable solvent; however, carbon dioxide extraction machines operate at pressures as high as 10,000 pounds per square inch. Because carbon dioxide is also an asphyxiate, an unintended release of the gas from the extraction equipment in an unventilated room could displace oxygen in the room and raise carbon dioxide to dangerous levels for workers. Oregon OSHA has established a permissible exposure limit (PEL) for carbon dioxide of 5,000 parts per million (ppm) averaged over an eight-hour work day.

If the amount of the carbon dioxide used for extraction could create an asphyxiation hazard, then a carbon dioxide gas detection system with a UL listing is required; the alarm should be set at 5,000 ppm for carbon dioxide.

The extraction room must have an exhaust system that provides a minimum of six air changes per hour – or one cubic foot per minute per square foot of solid floor – and explosion-proof or intrinsically safe fans. The exhaust system must increase ventilation to three cubic feet per minute per square feet if flammable gas vapors reach 20 percent of their lower explosive limit.

Oregon OSHA suggests setting lower explosive limit alarms to 10 percent of lower explosive limits so that exhaust ventilation rates will increase when flammable gas vapors are detected.

Exhaust outlets must be vented at least six feet above the roofline and at least 10 feet away from potential ignition sources and building openings. Air intakes must be at least 10 feet away from exhaust outlets.

Flammable liquid and gas storage rooms must be designed for Class 1, Division 2 locations in accordance with Oregon OSHA's Flammable Liquids rule, 1910.106. The exhaust system must provide at least one cubic foot per minute per square foot of continuous ventilation. Lower explosive limit gas monitors should be installed in gas storage rooms. Store compressed gas cylinders upright with safety caps in place, and secure the cylinders to prevent them from tipping over.

Butane is a highly flammable gas that has no odor. Butane's flash point (the lowest temperature at which its vapors will ignite with an ignition source) is minus 76 degrees F.

• The vapor volume for liquid butane is 32 cubic feet per gallon; this means that even a small release can cause an explosion from a spark or a static discharge.
• The density of butane gas is two times heavier than air; this means that butane gas will quickly settle to the floor. The accumulation of butane gas in enclosed areas presents a significant risk for explosions and fires.

Oregon OSHA's permissible exposure limit for butane is 800 parts per million (ppm) based on an eight-hour average. However, the American Conference of Governmental Industrial Hygienists (ACGIH) have established a 1,000 ppm recommended level based on a 15-minute average; this is equivalent to approximately 6 percent of butane's lower explosive limit, which can be exceeded during column cleaning.

An allergen is a substance that can trigger the immune system and cause an allergic reaction. People can have allergic reactions to cannabis, just as they do with many other plants. Symptoms vary from mild to severe. Initial exposures may show no symptoms, but exposures over time can lead to progressively stronger reactions.

Handling cannabis can cause hives, itchy skin, and swollen or puffy eyes in sensitive people. Breathing or inhaling cannabis allergens can result in shortness of breath, runny nose, sneezing, itching, and swelling and watering eyes.

Less common, cannabis can cause a severe allergic reaction called anaphylaxis. This condition can be life threatening and occurs within seconds or minutes of exposure.

There have also been cases of cross-reactivity between cannabis and certain foods, including tomatoes, peaches, grapefruit, apples, eggplant, bananas, and hazelnuts. Cross-reactivity happens when proteins in the cannabis plant, such as pollen, resemble the proteins in another plant. A person who comes into contact with a plant that has a similar protein could have an allergic reaction.

Currently, there is no standard way to test for a cannabis allergy; however, skin testing could be considered for patients who have experienced dermatological reactions to cannabis.

Sensitive workers who handle cannabis should use impervious coveralls, nitrile gloves, and N95 or N100 filtering face-piece respirators (dust masks) to reduce allergy symptoms. Employees experiencing serious allergic reactions should seek immediate medical attention. Allergic reactions are recordable events on the OSHA 300 log.

Carbon dioxide (CO2) – or dry ice in its solid form – is used in some cannabis extraction processes. Dry ice converts directly to carbon dioxide gas and can be hazardous to workers if not handled properly.

Under normal atmospheric concentrations, carbon dioxide is essentially colorless, odorless, and tasteless, and does not pose a health hazard. However, at levels exceeding 5,000 parts per million (ppm) averaged over eight hours, carbon dioxide displaces oxygen and can be toxic, causing respiratory acidosis – a serious medical condition that happens when there is too much carbon dioxide in a person's blood. Oregon OSHA has found carbon dioxide levels as high as 18,000 ppm in rooms where dry ice is used for extraction.

Symptoms of overexposure to carbon dioxide include headache, dizziness, rapid breathing, and increased heart rate; continued overexposure can cause unconsciousness and death.

Facilities that use carbon dioxide and dry ice must be equipped with a carbon dioxide detector that will sound an alarm when carbon dioxide exceeds 5,000 ppm. Carbon dioxide detectors must be properly maintained, calibrated, and used in accordance with the manufacturer's guidelines. Auto-calibrating and self-zeroing detectors must not be used.

Rooms where carbon dioxide or dry ice are used must also be properly ventilated. Carbon dioxide concentrations should be kept less than 1,400 ppm. Typically, one cubic foot of fresh air per square foot of solid floor will provide proper ventilation. However, a ventilation engineer should be consulted to determine the appropriate ventilation design.

Handle carbon dioxide carefully and with appropriate protective equipment. As a solid or a cryogenic liquid, carbon dioxide can produce painful burns when it contacts unprotected skin and sensitive tissue such as the cornea.

Safe practices

• Train employees about the health effects associated with carbon dioxide so they are able to recognize symptoms of overexposure and know the methods for controlling their exposure, the appropriate personal protective equipment to use, and how to respond to an emergency involving carbon dioxide.
• Require employees to use cryogenic gloves and safety glasses (or a face shield for liquid carbon dioxide) when they handle carbon dioxide to avoid contact with their skin or eyes.
• Secure carbon dioxide compressed-gas cylinders to a fixed object to prevent them from falling and use transportation carts to move cylinders.
• Cylinder safety caps must be in place when the cylinder is not attached to an extraction system.
• Ensure that pressure relief devices on high-pressure carbon dioxide extraction equipment and blow-off valves are piped to the exterior of the facility.
• Ensure that a carbon dioxide safety data sheet is accessible to employees and part of the facility's hazard communication plan.
• Do not use or store dry ice in confined areas, walk-in refrigerators, environmental chambers, or unventilated rooms.

All compressed gases are hazardous because they are used under high pressure. Most compressed gas cylinders have safety-relief devices that can prevent the cylinder from rupturing if internal pressure builds up to levels exceeding design limits. However, compressed gas can be released accidentally from a broken or leaking valve or from a safety device, and internal pressure can become dangerously high if a cylinder is exposed to fire or heat. Even under relatively low pressures, flammable compressed gases such as butane can burn or explode when they are released from a broken or leaking valve or from a safety device.

Compressed gases must be handled and used only by trained employees; those who handle, use, and inspect compressed gas cylinders must follow the Compressed Gas Association (CGA) guidelines referenced in  437-002-2101, Compressed Gases (General Requirements).

Store compressed gases by their hazard classification. Storage areas should be dry, well-drained, ventilated, and fire-resistant. Provide adequate space for compressed gas cylinders or segregate them by partitions and post a conspicuous sign that identifies the gas or its hazard class.

Compressed gas cylinders must also be visually inspected; follow the requirements in the Compressed Gas Association'sPamphlet C-6, Standards for Visual Inspection of Compressed Gas Cylinders. Leaking regulators, cylinder valves, or other equipment must immediately be taken out of service.

Remove equipment such as regulators, torches, and hoses before transporting compress gas cylinders, and never transport compressed gas cylinders in the passenger compartment of a vehicle. Make sure that the cylinder valve is closed and has been checked for leaks. If the cylinder valve is designed to have a valve cap, the cap must be in place when the cylinder is transported. Cylinders must also be secured in an upright position when they are transported.

Safe practices

• Know and understand the properties, uses, and safety precautions of the gases or gas mixtures being used.
• Ensure that safety data sheets are available for the gases at the facility.
• Ensure that cylinders are clearly identified. Labels must not be defaced or removed.
• Leave valve protection caps in place (if provided) until cylinders are secured and connected for use.
• Keep cylinder valves closed unless the cylinder is being used.
• Ensure that cylinders have one or more safety-relief devices.
• Never tamper with or alter cylinders, valves, or safety-relief devices.
• Do not place a cylinder next to a heat source or allow a flame to contact any part of the cylinder.
• Ensure that compressed gases are transferred from one container to another only by the gas supplier or people familiar with the hazards of the compressed gas.
• Ensure that compressed gases are stored upright and secured by chains or other means to prevent them from being knocked over. When cylinders are not in use, ensure that cylinder caps are in place.

We are more conductive than the ground we stand on, which means that if there is no other easy path, electricity will make a path through our bodies to return to its source. When we become part of the electrical circuit, the consequences are never good for us.

Electricity is a serious workplace hazard that can cause falls and burns, and do major damage to our internal organs. It should come as no surprise that the word electrocution is derived from electro and execution – electrocution is death caused by electric shock.

It is not necessarily the number of volts that will electrocute you, but the amount of current, its path, and the time it takes to pass through your body.

Common electrical hazards include:

• Improper use of extension cords
• Missing breakers
• Blocked electrical panels
• Damaged electrical cords
• Improper wiring
• Improper use of electricity in high-humidity and watering areas

Safety committee members should also be trained to identify and report electrical hazards during regular workplace inspections.

Safe practices

• Use only equipment that is approved by a nationally recognized testing laboratory.
• Do not modify extension cords or use them incorrectly.
• Use only factory-assembled extension cord sets and three-prong extension cords.
• Use extension cords and fittings that have strain relief.
• Do not use extension cords as a substitute for permanent wiring.
• Use ground-fault circuit interrupters on all 120-volt, single-phase, 15- and 20-ampere receptacles, or have an assured equipment grounding conductor program where electrical outlets are located in damp or potentially wet areas.
• Do not stand in wet areas when using portable electric power tools.
• Use distinctively marked double-insulated tools and equipment.
• Inspect electrical equipment to confirm that it is safe before using it.
• Remove from service any equipment with frayed cords, missing ground prongs, and cracked tool casings.
• Develop a written program for controlling hazardous electrical energy and ensure that workers follow its requirements. Note: Cord-and-plug connected equipment is not covered by Oregon OSHA's hazardous energy requirements if the equipment is unplugged, the plug is under the exclusive control of the operator, and electricity is the only form of hazardous energy.

Ethanol is a flammable liquid with a flash point of 55 degrees F and a boiling point of 173 degrees F. The flash point is the minimum temperature at which ethanol vapors can create an ignitable mixture in the air.

Ethanol's vapors are also heavier than air, which means the vapors do not rise in air and tend to accumulate at ground level until dispersed by wind or ventilation. For that reason, ethanol spills must also be quickly addressed because flammable vapors will form above all areas where the spills occur. Examples of typical ignition sources include electric arcs, furnaces, ovens, open flames, static electricity, and heat caused by friction.

Fires fueled by ethanol generate no visible smoke and have a blue flame that may be difficult to see. Ethanol fires are particularly challenging because they are not easily extinguished by traditional firefighting methods.

The National Fire Protection Association (NFPA) classifies ethanol as a Class 1, Division 2, Group D flammable liquid with lower and upper explosive limits of 3.3 percent and 19 percent, respectively, by volume in air. This is the range in which air concentrations of ethanol can ignite and burn in the presence of an ignition source.

Ethanol vapors must kept below the 3.3 percent lower explosive limit through adequate ventilation in storage areas. Adequate ventilation means that a ventilation system is capable of cycling a room's total air volume six times per hour. Exhaust ventilation should be located within 12 inches of the floor level.

The maximum flammable cabinet storage for ethanol is 60 gallons, and the maximum storage permissible outside a flammable storage cabinet or storage room is 25 gallons.

Inhaling ethanol can irritate the nose, throat, and lungs. Oregon OSHA has established a permissible exposure limit of 1,000 parts per million (ppm) for ethanol, averaged over eight hours. The ACGIH recommends a 1,000 ppm short-term exposure limit, based on a 15-minute average.

Use of ethanol for batch-soaking processes and rotary evaporation is covered by  1910.106(e)(3), Unit physical operations.

A flammable liquid is any liquid with a flashpoint at or below 199.4 degrees F. A flash point is the lowest temperature at which a liquid gives off enough vapor to ignite at the surface. However, many flammable liquids will ignite and burn easily at temperatures below 100 degrees F.

Flammable liquids are present in almost every workplace. Examples include ethyl and isopropyl alcohol, fuels, solvents, thinners, cleaners, adhesives, paints, waxes, and polishes.

Flammable liquids are divided into four categories, based on their flash points and boiling points:

• Category 1 includes liquids that have flash points below 73.4 degrees F and boiling points at or below 95 degrees F.
• Category 2 includes liquids that have flash points below 73.4 degrees F and boiling points above 95 degrees F.
• Category 3 includes liquids that flash points at or above 73.4 degrees F and at or below 140 degrees F.
• Category 4 includes liquids that flash points above 140 degrees F and at or below 199.4 degrees F.

Containers of Category 1 or 2 flammable liquids or Category 3 flammable liquids with a flashpoint below 100 degrees F must be bonded and grounded. Flammable liquids may be used only where there are no ignition sources within 50 feet. This includes electrical equipment and open flames.

PPE hazard assessments

PPE hazard assessments for work involving flammable liquids should address proper use and handling, fire safety, chemical toxicity, storage, and response to spills. Prepare a chemical inventory and review the safety data sheet for each chemical to determine proper use, handling, and procedures to follow after a spill or chemical release.

Safe practices

• Eliminate flammable liquids, substitute less flammable liquids, or reduce the quantities of flammable liquids used, if possible.
• Ensure that safety data sheets for flammable liquids are included in your hazard communication plan.
• Understand the bonding and grounding requirements for storing and transferring flammable liquids.
• Always work with flammable liquids under a chemical fume hood.
• Keep flammable liquid containers closed when the liquids are not being used.
• Keep flammable liquids at least 50 feet away from electrical outlets, electrical equipment, and other ignition sources.
• Use only enough flammable liquid to accomplish a task.
• Develop an emergency action plan and a fire protection plan and know the locations of emergency equipment, including fire alarms, fire extinguishers, and safety showers.
• Label all containers to identify that the contents are flammable.
• Do not put flammable liquids in “food-like" containers.

OSHA's hazard communication rules – there are rules for general industry, construction, and agriculture – require employers to train their employees to recognize chemical hazards and to take the necessary precautions to protect themselves. Most cannabis processors will follow the hazard communication requirements for general industry employers.

Oregon OSHA requires employers to inform employees of hazards and identities of chemicals they are exposed to in the workplace, as well as protective measures that are available. Workplaces whose employees may be exposed to hazardous chemicals must have a written hazard communication program that is specific to their workplace and includes:

• A list of all the hazardous chemicals in the workplace
• A description of the procedures for meeting the requirements for labels and other forms of warning, safety data sheets, and employee information and training
• A description of the methods for informing their employees about the hazards associated with nonroutine tasks and the hazards associated with chemicals in unlabeled pipes in their work areas

How to implement a hazard communication program:

• Review the hazard communication requirements for general industry employers (1910.1200) and designate a person responsible for implementing them.
• Prepare a list of all hazardous chemicals in the workplace.
• Ensure that the primary (shipped) labels on containers of hazardous chemicals are legible, in English, and prominently displayed on the container in the work area.
• Have and review the safety data sheet for each hazardous chemical that is used in the workplace, including residual pesticides encountered by workers doing field hand-labor operations. Safety data sheets must be readily accessible to all employees on all shifts. Where employees work at more than one workplace, safety data sheets may be kept at the primary workplace.
• Train employees about hazardous chemicals in their work area at the time of their initial assignment, and when a new physical or health hazard is introduced into their work area.
• Periodically reassess the program to make sure it is meeting its objectives and includes all hazardous chemicals in the workplace.

Most accidents that involve hazardous energy happen when workers release that energy on themselves or an unsuspecting co-worker. Energy exists in many forms, all of which are associated with motion – and it is motion that makes energy hazardous. The first step to control hazardous energy is to know the forms of energy that power the equipment you use and how that energy can harm you if you do not properly control it.

Lockout/tagout

Working on pressurized extraction equipment is extremely dangerous. Lockout/tagout refers to specific practices and procedures to safeguard employees from unexpected energizing of equipment, or the release of hazardous energy (such as compressed CO2 or flammable liquids) when the equipment is serviced or maintained. Most cannabis processors will follow the lockout/tagout requirements for general industry employers (1910.147).

Lockout/tagout requires, in part, that an authorized person turn off and disconnect the machinery or equipment from its energy sources before performing service or maintenance and either lock or tag the energy-isolating devices to prevent the release of hazardous energy. Authorized employees also should take steps to verify the energy has been isolated effectively.

Lockout devices hold energy-isolation devices in a safe or “off" position. They provide protection by preventing machines or equipment from becoming energized. They cannot be removed without a key or other unlocking mechanism. Tagout devices are prominent warning signs that fasten to energy-isolating devices to warn employees not to re-energize the machine while it is being serviced or repaired.

Lockout/tagout procedures

Employers must develop, document, and use lockout/tagout procedures for controlling hazardous energy. Documenting the required procedure for a particular machine or equipment is not necessary, however, when all of the following are true:

• The machine or equipment has no potential for stored or residual dangerous energy or accumulation of stored dangerous energy after shutdown
• The machine or equipment has an easily identified and isolated single energy source
• The isolation and locking out of the energy source will eliminate all energy-related hazards
• The machine or equipment is isolated from that energy source and locked out during servicing or maintenance
• A single lockout device will achieve a locked-out condition
• The lockout device is under the exclusive control of the authorized person doing the servicing or maintenance
• The servicing or maintenance does not create hazards for other employees
• No incidents have happened that involved the unexpected activation or energizing of the machine or equipment during servicing or maintenance

Training

Authorized persons must be trained to recognize sources of hazardous energy, the type and amount of energy in their workplace, and methods to isolate and control the energy. Other employees who work where energy control procedures are used must be trained about those procedures and not to restart or energize locked out or tagged out machines or equipment.

When workers' jobs involve awkward postures or excessive effort to complete a task, fatigue and discomfort are often the result. As those jobs are repeated over and over, muscles, tendons, ligaments, nerves, and blood vessels are damaged. The resulting injuries are called work-related musculoskeletal disorders (WMSDs). They are also known as overexertion injuries, cumulative traumas, and repetitive motion injuries.

Unless we give our bodies enough time to recover or we change the work so that it is less stressful, we are setting ourselves up for a work-related musculoskeletal disorder.

Work-related musculoskeletal disorders are easier – and less expensive – to treat in their early stages, but if left untreated, they can quickly become disabling.

Symptoms of work-related musculoskeletal disorders include:

• Pain from movement, pressure, or exposure to cold or vibration
• Change in skin color from exposure to cold or vibration
• Numbness or tingling in an arm, leg, or finger, especially in the fingertips at night
• Decreased range of motion in the joints
• Decreased grip strength
• Swelling of a joint or part of the arm, hand, finger, or leg
• Fatigue or difficulty in sustaining performance, particularly of small muscle groups

Work-related musculoskeletal disorders can happen when workers do tasks necessary to accomplish their jobs in ways that put too much stress on their bodies. Some jobs have only one task, but most jobs have many tasks. How do you know which tasks are causing a musculoskeletal disorder? One way is to identify the factors that create risks for musculoskeletal disorders.

Risk factors are the parts of tasks that stress the body and increase the possibility of injury. They include:

• Awkward postures
• Excessive force
• Repetitive motion
• Pressure points
• Vibration
• Hot and cold temperatures
• Eyestrain

When you identify the risk factors your employees are experiencing, you will have a better understanding of how musculoskeletal disorders happen and then you can take steps to control them.

Common tasks and risk factors associated with WMSDs in cannabis extraction and processing environments include:

• Manually lifting heavy objects such as extraction columns
• Awkward postures caused by handling extraction columns above the shoulders and stooping to adjust collection vessels
• Repetitive hand work during packaging

Personal protective equipment protects workers from hazards such as chemicals, electricity, fumes, sharp objects, and noise. Personal protective equipment – usually called PPE – includes items such as goggles, coveralls, gloves, vests, earplugs, and respirators.

PPE, when used properly, protects against hazards, but does not eliminate them. Although PPE is another way to control a hazard, it is only a barrier between the hazard and the worker. When PPE does not properly fit a worker or the worker does not use it correctly, the worker risks exposure.

You must do a hazard assessment to determine if your workplace has hazards that you cannot eliminate or control without PPE. A hazard assessment is an evaluation of your workplace that helps you determine what hazards your employees are exposed to and what PPE they need to protect themselves. A hazard assessment should include:

• The jobs (or tasks) that your employees do
• The hazards your employees are exposed to
• Where the hazards are located
• The likelihood that those hazards could injure your employees
• The severity of a potential injury
• The types of PPE necessary to protect your employees from those hazards

You must also prepare a document that says you have done the hazard assessment. The document must include:

• A heading that says the document is a “certification" of the hazard assessment
• The name of the workplace evaluated
• The name of the person certifying the hazard assessment was completed
• The date of the hazard assessment

If you determine that your workplace has hazards that cannot be eliminated or controlled without PPE, then you must:

• Select the PPE that protects your employees from the hazards
• Communicate your selection decisions to each affected employee
• Ensure that the PPE fits each employee
• Require your employees to use their PPE when they are exposed to the hazards

Always train employees how to wear, use, and maintain their PPE before they use it the first time. Training must also include the types of PPE that are necessary and the limitations of the PPE.

Pressure relief valves are safety devices designed to protect a pressurized vessel or other pressurized system so that its maximum pressure rating is not exceeded. There are many types of pressure relief valves, which must be properly matched with the appropriate equipment; this is especially important for extraction systems. The ASME Boiler & Pressure Vessel Code sets the requirements for the design and construction of pressure vessels and pressure relief valves. Pressure relief valves must be tagged to identify the specific relief pressure. Pressure relief valves for carbon dioxide extractors must be vented outdoors.

A pressure vessel is a storage tank that has been designed to operate at pressures above 15 psig (pounds per square inch, gauge). Examples of pressure vessels used in cannabis processing include evaporators, columns, kettles, heat exchangers, and condensers.

Cracked and damaged pressure vessels can leak or rupture. Potential health and safety hazards of leaking vessels include poisoning, suffocation, fire, and explosion. Ruptures can cause considerable damage to life and property.

The ASME Boiler & Pressure Vessel Code sets the requirements for the design and construction of boilers and pressure vessels. All pressure vessels must be designed and stamped with a unique ASME Boiler & Pressure Vessel Code number, which makes it possible to determine the materials, procedures, welding, and testing done on the equipment.

“Laboratory-safe" or “Flammable safe" refrigerators are required for storing or processing refrigerated flammable liquids. These refrigerators are constructed with all electrical components and compressors located outside of the refrigerated storage compartment, which prevent ignition of flammable vapors inside the refrigerator. Never use household refrigerators – which may produce sparks, arcs or flames inside the refrigerated compartment – to store flammable liquids.

The NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals, has more information about using refrigerators to store flammable liquids.

A rotary evaporator is a device used to remove a volatile solvent from a nonvolatile sample by evaporation. Typically, a rotary evaporator is used as a post-extraction refinement method after ethanol extraction. After the product is dissolved in ethanol, the rotary evaporator sends the product through vacuum lines into an evaporation chamber, then to a rotating flask that floats over a water bath; the result is a controlled precipitation of volatile solvents.

Rotary evaporator hazards include implosions resulting from the use of defective glassware, explosions caused by leaks within the system, and overconcentrations of volatile solvents during evaporation. Use a rotary evaporator in a Class 1, Division 2 location and ensure that the area is ventilated at a rate not less than one cubic foot per minute per square foot of solid floor.

Users of rotary evaporators must also take precautions to avoid contact with rotating equipment parts, particularly entanglement of loose clothing, hair, or necklaces.

Investigations by Oregon OSHA compliance officers have found that the failure of sanitary clamps is a leading cause of explosions involving extraction equipment in hydrocarbon extraction facilities.

A sanitary clamp is a fitting designed to quickly seal a connection between pipes, tubes, valves, and pumps used in extraction processes. Typically, the connection consists of two end pieces – called ferrules – that provide a mating surface for the connection; a gasket that provides a leak-proof seal between the ferrules; and the clamp, which keeps the components secure.

An improper connection can lead to catastrophic equipment failures when the equipment is operating under extreme temperatures and pressures. While they are relatively simple in design, sanitary clamps must be used correctly to ensure a safe, leak-free connection. Those who use sanitary clamps must be properly trained in their use and understand how to inspect, install, and maintain them. Brass connecting bolts should be inspected before each use and replaced frequently to reduce the risk of catastrophic failure. Torque wrenches should be used to set bolts in accordance with manufacturer guidelines.

Vacuum ovens are used to remove moisture, gas, and volatile chemicals from products without burning or damaging the product. They are commonly used to process cannabis extracts such as butane hash oil. Residual solvents evaporate in the vacuum chamber and are removed by the vacuum, leaving behind the pure oil extract.

Vacuum ovens must not be used to process volatile gases and other flammable liquids unless the vacuum oven is rated to process them. Vacuum ovens must also be listed by a nationally recognized testing laboratory.

Winterization is a method of removing waxes and lipids from crude cannabis extract, which typically follows ethanol or carbon dioxide extraction processes. Raw cannabis extract is dissolved in ethanol at sub-zero temperatures, which separates the waxes and lipids from the extract. “Laboratory-safe" or “Flammable safe" refrigerators are required for winterizing refrigerated flammable liquids such as ethanol.