The COVID-19 pandemic required leaders at workplaces from grocery stores to hospitals to make crucial decisions about how to manage the spread of infectious respiratory viruses.

CDC and OSHA emergency temporary standards (ETS) provided some direction, but now that those standards have expired or been repealed, how can we ensure we are protecting workers from respiratory viruses and promoting workplace safety?

Lisa Brosseau, Sc.D., CIH, research consultant at the University of Minnesota Center for Infectious Disease Research and Policy, argues for a permanent workplace safety and health standard for infectious respiratory viruses in a recent webinar sponsored by our Industrial Hygiene Practice Specialty.

While OSHA has an infectious disease prevention rule on its current regulatory agenda, the long rulemaking process is still in its infancy and is largely focused on healthcare settings, she says. More can and should be done to guide organizations to an accepted standard for overall workplace safety.

Her webinar touches on key terms for understanding the nuance of respiratory virus transmission, the historical context of OSHA regulation and the elements that should inform a permanent standard.

Need-to-Know Respiratory Virus Terms: Droplet vs. Airborne vs. Aerosol

Traditionally, experts in the infection control and healthcare fields have thought about infectious respiratory disease transmission in two ways: droplet versus airborne, Brosseau says.

Droplet transmission has been defined as occurring when an infected person is talking, coughing or sneezing, releasing particles that come in contact with the eyes, nose or mouth of another person at close range (3 to 6 feet). These particles are typically larger and propelled through the air onto the mucus membranes of someone nearby. This mode of transmission does not involve inhalation.

Airborne transmission involves inhalation and has been traditionally defined to occur only when tiny particles (droplet nuclei) spread through the air over long distances, such as across a large stadium and through a ventilation system. This mode of transmission does not consider the dispersion of particles into a shared space.

Today we understand that people generate a wide range of particle sizes when they breathe, talk, sing, cough or sneeze. If the person has an infectious disease, such as a respiratory virus like influenza or COVID-19, their respiratory particles can contain infectious organisms. These particles – large and small – are inhalable at both near and far distances. With time, an indoor space can be filled with infectious particles that remain suspended in air for long periods of time.

Rather than separate particles into “droplet” and “airborne,” it is more appropriate to use the term “aerosol,” which is defined simply as a suspension of particles in air. Diseases that transmit by inhalation both near and far from an infected person or source should be referred to as “aerosol transmissible.” And, most importantly, inhalation should be considered the primary means by which such particles transmit disease. Droplet propulsion may be possible, but it is much less important and likely than inhalation. Thus, there is no need to divide infectious diseases into separate “droplet” and “airborne” categories. All such diseases are “aerosol transmissible."

OSHA Has Attempted to Regulate Infectious Disease Exposures in the Past

The COVID-19 pandemic was not the first time OSHA attempted to implement regulations regarding infectious diseases. The agency first introduced the Bloodborne Pathogens Standard in 1991, but that is specific to certain pathogens like HIV and HBV and does not address respiratory diseases or infectious aerosols.

• OSHA’s first regulatory actions for an aerosol transmissible disease  concerned tuberculosis (TB) in the 1990s: In the late 1980s and early 1990s, there was an increase in TB infections and deaths among workers exposed to HIV-positive people in high-risk locations such as healthcare and correction facilities, Brosseau explains. This prompted OSHA to issue enforcement procedures in 1993, which included requirements for respiratory protection.and adherence to the general duty clause.
  
  After some stakeholders called for a permanent standard, OSHA published a proposed rule for Occupational Exposure to Tuberculosis that followed CDC guidelines. It recommended facilities conduct exposure assessments to identify which employees are likely to be exposed, ranking their risk level among five categories and implementing corresponding interventions.
  
  However, OSHA received pushback on the rule and withdrew it in 2003 as the rate of TB was falling. The agency continues to recommend adherence to the general duty clause.
  
  
• California’s 2009 ATD standard: This comprehensive standard, which covers healthcare and related workplaces such as emergency responders, requires an exposure control plan and employee training. Notably, it applies to droplet or airborne diseases or novel or unknown pathogens for which there is no evidence to rule out the possibility that they are aerosol transmissible.
  
  Companies must determine occupational exposure based on tasks, activities and environment and identify specific control measures, such as engineering, work practices, cleaning, disinfection or PPE.
  
  
• 2015 Hospital Respiratory Protect Program Toolkit: After a 2012 study found that many hospitals in California were not fully following the ATD standard — respiratory protection programs lacked administrators, employees didn’t know how to find or properly wear respirators — NIOSH and OSHA published a toolkit, which was updated in 2022, to ensure greater compliance.
  
  
• OSHA’s current attempts at an infectious disease standard: In 2010, OSHA initiated public fact-finding and proposed a worker infection control program but tabled it in 2017. In spring 2023, the agency stated its intent to issue a notice of proposed rulemaking, but so far it hasn’t done so.

“I think we need an infectious disease standard,” Brosseau says. “I’m glad OSHA’s working on one. I’m sorry that the TB standard didn’t get changed into or become an infectious disease standard as that would have been useful during the pandemic.”

How the COVID-19 Pandemic Changed the Rules

When the COVID-19 pandemic took hold, it highlighted a significant problem with existing standards: They are primarily focused on healthcare settings. But transmission was happening everywhere.

“Anyone who couldn’t stay home was at risk,” Brosseau says, with the highest risk outside healthcare affecting transportation, manufacturing and personal service workers. The risk factors were the same everywhere: Many contacts, long exposure times, low ventilation and shared spaces.

While federal and state OSHA agencies in Virginia, Michigan, Oregon and California attempted to address these workplace safety risks, all measures have since expired or been repealed as the pandemic officially ended in 2023.

However, these standards raised several key issues OSHA must address as it develops a permanent standard, including determining means of contact transmission, especially for novel or unknown diseases; identifying risk factors based on source proximity; the frequency, type and nature of contacts; and how to combine those risk factors to determine exposure.

What a Model Infectious Disease Standard Should Include

Despite some hurdles in creating regulations, Brosseau argues that a permanent standard on infectious respiratory viruses is needed, not only for future outbreaks, but because COVID-19 and other respiratory viruses such as influenza continue to cause mortality, illness and lost work.

Through her research, she has identified the elements that an infectious disease standard must include:

• Move beyond the classic droplet versus airborne paradigm.
• Take a precautionary approach, which means presuming aerosol inhalation of infectious respiratory viruses or use a weight-of-evidence approach to determine biological plausibility for any mode of transmission.
• Consider all infectious diseases in the context of work.
• Use qualitative or semi-qualitative approaches, including control banding, to identify levels of risk.
• Prioritize healthcare but consider application to all workplaces.

The standard should require all workplaces to have a written program for managing infectious respiratory viruses, Brosseau says. This program should incorporate:

• Hazard identification
• Exposure assessment
• Interventions following the hierarchy of controls
• Ongoing assessment of program effectiveness

While Brosseau views these aspects as essential for a permanent standard, safety professionals and workplace safety and health agencies should take other steps to further protect workers from exposure to respiratory viruses while on the job.

What else is needed?

• More collaborative and shared decision-making between public health, infection prevention and control, and occupational safety and health, disciplines Brosseau says are currently too siloed.
• Additional epidemiological information collected about occupation and job tasks. “If we had known who was being infected, we would have known who was at risk,” Brosseau argues. “We know more about demographics than we do about occupation and job tasks and that’s unfortunate.”
• OSHA should not be required to follow CDC guidelines to ensure its efforts aren’t  hindered by another agency’s timelines.
• More consideration of pre- and asymptomatic transmission. “It happens more frequently than you’d expect,” she says.
• A review of the role of various controls, such as barrier face coverings, facemasks and respirators, dilution versus local exhaust ventilation in many settings, rapid antigen tests and other PPE such as goggles.

Finally, Brosseau says that an OSHA standard is vital to prevent respiratory virus outbreaks in the workplace. Without one, safety professionals often must rely on guidelines from the CDC, which has no regulatory authority and does not complete inspections like OSHA to ensure compliance.

“If you don’t have a standard then you don’t really know what the performance should be,” she says. “You need measurements and levels before you can sell something and say, ‘Yes it’s going to work.’”

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