Thermal Work Environments – Part 9: Managing Conditions in Cold Environments

     Throughout the range of possible workplace temperatures, safeguarding the health and well-being of employees is paramount.  Despite equal importance, the development of a coordinated program to prevent cold injury receives much less attention than its heat-related counterpart.
     An effective cold injury prevention program consists of the same components as a heat illness prevention program.  These include the measures used in environmental assessment, exposure limits, policies and procedures, training plans, program assessment processes, and other information relevant to work in a cold environment.  Like its heat-related counterpart, this is nominally a prevention program; however, information about the proper response to the occurrence of cold injury, such as first aid practices, is also included.
     Given the similar natures of the heat- and cold-related programs, it should come as no surprise that this installment of the “Thermal Work Environments” series parallels that of “Part 5:  Managing Conditions in Hot Environments.”  In the outline for a cold injury prevention program that emerges, cold stress hygiene and various control mechanisms are introduced.  This outline can be customized to the specific needs of an organization or workplace.

     The content of a cold injury prevention program is presented in five (5) sections:

• Training
• Hazard Assessment
• Controls
• Monitoring
• Response Plans

To reiterate, the information presented here is only an overview.  An exhaustive treatment is not feasible in this format, given the range of potential workplace scenarios that exists.  Instead, it is intended to identify avenues of inquiry to be explored in the context relevant to developers of a specific program.

Training
     Every person that works in or has responsibility for a cold workplace should be trained on the ramifications of overexposure to cold conditions.  An effective training program includes information discussed in the following four sections.  Topics important to all team members include:

• basics of human biometeorology and heat balance,
• environmental, personal, and behavioral risk factors,
• methods used to monitor conditions,
• controls in place to prevent cold injury,
• signs and symptoms of cold injury, and
• first aid and emergency response procedures.

Training of supervisors and team leaders should emphasize proper use of controls, signs and symptoms, and appropriate responses to cold injury.
     A complete training plan includes the content of the training and a schedule for delivery.  It may be best to distribute a large amount of information among multiple modules rather than share it in a single, long presentation.  Refresher courses of reduced duration and intensity should also be planned to combat complacency and to update information as needed.  Refreshers are particularly helpful when dangerous conditions exist intermittently or are seasonal.
 
Hazard Assessment
     An initial hazard assessment consists of identifying the elements of job design (see Part 1) that are cold-related.  These include site-specific environmental factors, such as:

• atmospheric conditions (e.g. temperature, humidity, sun exposure),
• air movement (natural or forced), and
• precipitation (i.e. rain or snow that can wet clothing or exposed skin).

Job-specific attributes are also documented.  These may include:

• intensity of work (i.e. strenuousness and rate),
• dexterity requirements of work,
• tools and materials to be handled,
• personal protective equipment (PPE) and other gear required, and
• access to food, water, and a warm recovery area.

As many relevant factors as possible should be identified.  Special attention must be paid to compounding risks.  For example, a task requiring high dexterity in the presence of fluids compounds the risk of exposed skin (gloves limit dexterity) with the risk of wetted skin and clothing.
     The information collected in the hazard assessment is used to create a risk profile for each task or logically-grouped series of tasks.  Development of controls and modifications of job design are prioritized according to the risk profiles generated.
 
Controls
     Readers are reminded that there is a hierarchy of controls that can be implemented to address a hazard.  The hierarchy is represented by an inverted pyramid, as shown in Exhibit 1.  The most-effective types of controls – elimination and substitution – are not realistic options in many thermal environments.  Repair of a bridge or other structure cannot be postponed until spring and a construction site cannot be relocated to a more hospitable environment.

     Therefore, the focus of this presentation is, necessarily, on the remainder of the hierarchy which represents feasible protection opportunities.  Engineering controls modify the tasks performed, equipment used, or the operating environment.  Administrative controls reduce cold injury by guiding workers’ behavior.  Finally, PPE is used to manage cold stress not eliminated by other measures.
     A comprehensive cold injury prevention program considers every term in the heat balance equation (see Part 6), developing appropriate mitigations for each.  Examples of engineering controls include:

• Heaters of various types – area heaters warm the entire workspace; spot or infrared (IR) heaters warm the worker without significantly heating the surroundings; chemical heat packs and electrically-heated garments provide a heat source that moves with the person.
• Wind barriers reduce the wind chill effect.
• Tool covers minimize conductive heat loss (K) by covering metals with lower-conductivity material, such as plastic or rubber.
• Splash/spray guards limit contact with fluids, minimizing evaporative heat loss (E) and limiting loss of insulation capability of clothing.
• Equipment designed with large buttons, knobs, dials, etc. facilitate use while wearing gloves or mittens.
• Use of alternative control devices, such as a stylus for a touchscreen, avoid removal of protective gear for routine tasks.
• Use of lift assists or other physical aids maintain work rate with minimum risk of sweating (i.e. stabilize metabolic heat generation, M).

Administrative control examples include:

• Implementing a “buddy system” allows two (or more) people to effectively manage their work rates (minimize sweating, etc.) by sharing work and provide each other constant monitoring for signs of cold injury.
• Developing a balanced work cycle avoids periods of intense effort followed by periods of very low intensity.  Long periods of sitting or standing are also avoided.
• Implementing an acclimatization program provides an adjustment period to new or returning workers.  While there is consensus that heat acclimatization is effective in preventing many heat illnesses, the same does not appear to be true for cold acclimatization.  It is recommended, nonetheless, because evidence suggests that cold acclimatization does, in fact, occur to some degree, improving safety.
• Implementing a work/warm-up schedule limits the duration of exposure.  The schedule shown in Exhibit 2 has been cited in Canadian provincial regulations and as ACGIH TLVs.  Exhibit 3 provides a visual representation of a 4-hour work cycle in the no-wind condition.  The supplement shown in Exhibit 4 combines the two styles of representation in a single reference.  All work/warm-up schedules assume that workers’ clothing is dry.
• Encouraging consumption of snacks and warm drinks throughout the workday helps workers maintain energy and hydration.
  

     Cold-related PPE includes all garments worn for insulation, wind protection, or waterproofing.  This includes insulated boots, goggles, gloves, hats, neck gaiters or scarves, balaclavas, etc.
     Clothing should be worn in loose-fitting layers.  Multiple layers provide improved insulation performance and facilitate adjustment as needs change.  The innermost layers should be capable of wicking moisture away from the skin.  Garments made of synthetic fibers are often used for this purpose; cotton is not recommended, as it wets easily, reducing its insulating capability.
     A waterproof outermost layer or windbreaker may be needed, depending on conditions.  Adjustable closures (waist, neck, arms) and vents (armpits, etc.) allow the wearer to accommodate a wider range of conditions before changing is necessary.  Intermediate layers must be selected in accordance with environmental conditions and work performed (e.g. work rate or intensity).
     It is important to remember that clothing that is wet, dirty, or compressed loses insulation capacity.  This is particularly important to remember in regards to socks.  Thick, insulated socks may be counterproductive if their bulk causes boots to be tight-fitting.  Restricted circulation and impaired insulation accelerates the onset of trench foot and/or frostbite.

     Controls used in conjunction must be evaluated to ensure suitability of the combination.  For example, a well-balanced work cycle may render heated garments excessive and, therefore, counterproductive.  Likewise, using a physical aid to move a light load may cause a problem; effort is reduced, lowering M, while heat loss (K) in the extremities may be increased via physical contact with the equipment.  Another example is the construction of an effective wind barrier that, in addition to its direct benefit, precludes the need for a splash guard that hinders task performance.  Sometimes less is more.
 
Monitoring
     Monitoring is a multifaceted activity and responsibility.  In addition to measuring environmental variables, the effectiveness of controls and the well-being of workers must be continually assessed.  A monitoring plan includes descriptions of the methods used to accomplish each.
     Measurement of environmental variables is the subject of Part 8 of this series.  As discussed in that installment, decisions regarding work cycle modifications or stoppages is often based on wind chill calculations.  Though imperfect, it is a useful guide that provides early warnings that additional precautions may be needed to protect workers during particularly dangerous periods.  In addition to providing wind chill charts, the National Weather Service (NWS) issues advisories when dangerous conditions are forecast.
     After controls are implemented, they must be monitored for proper use and continued effectiveness.  This should be done on an ongoing basis, though a formal report may be issued only at specified intervals (e.g. quarterly) or during specific events (e.g. modification of a control).  Verification test procedures should be included in the monitoring plan to maintain consistency of tests and efficacy of controls.
     Monitoring the well-being of workers is a responsibility shared by a worker’s team and medical professionals.  Prior to working in a cold environment, each worker should be evaluated on his/her overall health and underlying risk factors for cold injury.  An established baseline facilitates monitoring a worker’s condition over time, including the effectiveness of acclimatization procedures and behavioral changes.
     Suggestions for behavioral changes, or “lifestyle choices,” can be made to reduce a worker’s risk; these include diet, exercise, consumption of alcohol or other substances, and other activities.  Recommendations to an employer regarding one’s fitness for certain duties, for example, must be made in such a way that protects both safety and privacy.  Cold-related issues may be best addressed as one component of a holistic wellness program such as those established by partnerships between employers, insurers, and healthcare providers.
 
Response Plans
     There are three (3) response plans that should be included in a cold injury prevention program.  Like heat-related response plans (see Part 5), two of them are concerned with cold injury that was not prevented.
     The first response plan details the provisioning of first aid and subsequent medical care when needed.  Refer to Part 7 for an introduction to cold injuries and first aid.
     The second outlines the investigation required when a serious cold injury or cold-related accident occurs.  The questions it must answer include:

• Were defined controls functioning and in proper use?
• Had the individual(s) involved received medical screening and been cleared for work?
• Had recommendations from prescreens been followed by individual(s) and the organization?
• Had the individual(s) been properly acclimatized?
• Were special circumstances involved (e.g. wind chill advisory, emergency situation, etc.)?

The investigation is intended to reveal necessary modifications to the program to prevent future cold injuries and related accidents.
     The final response plan needed defines the review process for the cold injury prevention program.  This includes the review frequency, events that trigger additional scrutiny and revision, and required approvals.


     Currently, management of cold work environments is governed by the “General Duty Clause” of the Occupational Safety and Health Act of 1970.  The General Duty Clause provides umbrella protections for hazards that are not explicitly detailed elsewhere in the regulations.  It is a generic statement of intent that provides no specific guidance for assessment of hazards or management of risks.
     Though OSHA has issued an “advance notice of proposed rulemaking” (ANPRM) to formalize heat-related safety regulations and launched a National Emphasis Program for heat-related hazards, no counterpart for cold conditions has yet been publicized nor is cold stress addressed in the OSHA Technical Manual; in fact, the major players in US industrial hygiene (OSHA, NIOSH, ACGIH) do not prescribe a cold injury prevention program.
     That a standard promulgated by OSHA or other prominent organization will reduce illness and injury in thermal work environments is a reasonable expectation.  However, it must be recognized that it, too, is imperfect.  No standard or guideline can account for every person’s unique experience of his/her environment; therefore, an individual’s perceptions and expressions of his/her condition (i.e. comfort and well-being) should not be ignored.  A culture of autonomy, or “self-determination,” where workers are self-paced, or retain other responsibility for thermal stress hygiene, is one of the most powerful tools available for safety and health management.
 
 
     For additional guidance or assistance with complying with OSHA regulations, developing a cold injury prevention program, or other Operations challenges, feel free to leave a comment, contact JayWink Solutions, or schedule an appointment.

     For a directory of “Thermal Work Environments” entries on “The Third Degree,” see Part 1:  An Introduction to Biometeorology and Job Design (17May2023).
 
References
[Link] Kodak's Ergonomic Design for People at Work.  The Eastman Kodak Company (ed).  John Wiley & Sons, Inc., 2004.
[Link] “Threshold Limit Values for Chemical Substances and Physical Agents.”  American Conference of Governmental Industrial Hygienists (ACGIH); latest edition.
[Link] “Thermal Environment.”  Student Manual, Occupational Hygiene Training Association; February 2016.
[Link] “Fire and Ice: Protecting Workers in Extreme Temperatures.”  Donald J. Garvey.  Professional Safety; September 2017.
[Link] “Hierarchy of Controls.”  NIOSH; January 17, 2023.
[Link] “Preventing Cold-related Illness, Injury & Death among Workers.”  NIOSH Publication No. 2019-113; September 2019.
[Link] “Cold Environments - Working in the Cold.”  Canadian Centre for Occupational Health and Safety (CCOHS); June 13, 2023.
[Link] “Working in Cold Conditions Fact sheet.”  Canadian Centre for Occupational Health and Safety (CCOHS); October 28, 2022.
[Link] “Staying safe in the cold - & tips for safety pros and workers.”  Barry Bottino.  Safety + Health; January 29, 2023.
[Link] “Working in the cold – Stay safe when temperatures drop.”  Alan Ferguson.  Safety + Health; November 22, 2020.
[Link] “Cold Stress and its Safety Measures.”  OSHA Outreach Courses: July 30, 2021.
[Link] “Recommendations to Improve Employee Thermal Comfort When Working in 40°F Refrigerated Cold Rooms.”  Diana Ceballos, Kenneth Mead, and Jessica Ramsey.  Journal of Occupational and Environmental Hygiene; August 17, 2015.

Jody W. Phelps, MSc, PMP®, MBA
Principal Consultant
JayWink Solutions, LLC
[email protected]