Exploring occupational asthma
Substituting, removing exposures key to protecting workers
In 2003 in Michigan, a manager of a vehicle detailing business sprayed a truck bed liner on the floor and sides of a cargo van. After the manager finished the task, a co-worker saw that he was having trouble breathing. They went to an urgent care facility and the manager was transported to an emergency room, where he died.
A report from the Michigan Fatality Assessment and Control Evaluation Program listed the cause of death as “acute asthmatic reaction due to inhalation of chemicals.” Several factors could have played a role, including confinement of the vapors, which may have increased the worker’s potential exposure to isocyanate – one of the most common chemicals linked to work-related asthma. The worker was not adequately fitted for his respirator, nor was he trained on how to use it. In addition, his employer lacked a hazard communication program.
The report illustrates the dangers of work-related asthma.
About 11 million workers are exposed to at least one agent associated with occupational asthma, according to OSHA. And a report from the Centers for Disease Control and Prevention, published in the Dec. 2 issue of Morbidity and Mortality Weekly Report, concluded that as many as 2.7 million U.S. workers may have asthma caused or aggravated by workplace conditions.
“Asthma in general is on the increase in the United States,” said Vincent Castranova, professor of pharmaceutical sciences at West Virginia University and former chief of the Pathology and Physiology Research Branch in NIOSH’s Health Effects Laboratory Division. “There’s questions about why. One answer is our ability to diagnose it is much better, and the education of physicians to look for it in the occupational setting is much increased.”
What is it?
Asthma is a lung disease in which the airways become inflamed and narrow. Symptoms can include wheezing, coughing, chest tightness and shortness of breath. Exposure to irritants and substances, such as pollen or smoke, can trigger it. People who smoke and those who have a family history of allergies have a higher risk for developing asthma, according to the Milwaukee-based American Academy of Allergy, Asthma and Immunology.
“If an employee’s asthma is not well-controlled, it can have a significant impact on both that person’s productivity at work and overall ability to function well in life, and it can cost the employer substantial amounts of money beyond just functioning at work in terms of trips to the emergency room and hospitalizations,” said Polly Hoppin, research professor and program director of the Environmental Health Program at the Lowell Center for Sustainable Production at the University of Massachusetts-Lowell.
Occupational asthma can occur when a worker is exposed to on-the-job substances such as dust, chemicals or mold, OSHA states. A worker can be exposed through breathing or skin contact.
“What’s been learned over the last decade or so is your sensitization might not have occurred by inhalation – it might have occurred by dermal exposure,” Castranova said. “Latex gloves are the hallmark of that. It could be mainly dermal exposure. You became sensitive to the latex protein through skin exposure, and that affected your immune system. Then a very low exposure in the air could give an asthmatic event.”
Work-related asthma can be broken down into types.
Asthma resulting from sensitization to a substance – such as a chemical or allergen – may develop hours, days, weeks or even years after the first exposure.
Asthma induced by an irritant – also called Reactive Airways Dysfunction Syndrome – is caused by a high-level exposure to a substance. In addition, a workplace exposure can exacerbate preexisting asthma.
The Mayo Clinic notes that more than 300 workplace materials may cause occupational asthma, including animal substances, enzymes and metals.
“In an office setting, there can be chemicals that cause or contribute to asthma in furniture or building materials,” Hoppin said. “There can be particular exposures like flour in the bakery industry, or several hundred chemicals used in manufacturing processes – such as isocyanates or formaldehyde – that can contribute to asthma when workers are exposed. Work environments can have mold or dust, just as homes can.”
Symptoms can begin while on the job or within hours of leaving work, according to OSHA, and may persist even when exposure stops. If not treated, long-term lung damage, disability and death can result.
“If it’s treated early and identified early, typically the prognosis is very good, depending on how much airway obstruction there is,” said Dr. Jonathan Bernstein, an associate professor of internal medicine at the University of Cincinnati who specializes in allergy and asthma.
Dr. Jonathan Bernstein
University of Cincinnati
How is the diagnosis made?
Determining if asthma is work-related can be a challenge, experts say. “People often don’t get good work histories and understand the importance of a good occupational history, so therefore it’s missed by clinicians,” Bernstein said. “The other issue is that many times workers leave the workplace because they don’t do well health-wise, so it doesn’t get reported.”
Work histories and Safety Data Sheets are crucial for identifying agents affecting the worker, Bernstein added. Doctors may have to talk to the company and safety officers and learn the work processes to determine the exposure.
Symptoms of work-related asthma may improve when the worker is away from the job, but that isn’t always the case.
“Some people go to work and they don’t have symptoms right away, and it might be several hours or a couple days at work and they start developing symptoms,” Bernstein said. “It goes away over the weekend and comes back when they go back to work. As it becomes more chronic, [symptoms] might be persistent throughout the weekend. Sometimes, people have no symptoms and have trouble at night, so they don’t consider the workplace as a cause.”
What is the employer’s role?
So what can employers do?
“The first order of business, once that individual has been taken care of, would be to look at the work environment and determine what can be done to reduce exposures, not just for that person’s benefit, but for others who may currently or in the future be affected,” Hoppin said.
Measures for protecting workers can include training, improved ventilation, proper housekeeping and replacing substances with less harmful alternatives – or, if that is impossible, minimizing exposure through engineering controls.
The best way to prevent asthma exacerbation and new cases is to substitute products and processes, and limit exposure of asthma-related chemicals, according to the Toxics Use Reduction Institute at UMass Lowell. Current exposure limits established by OSHA and other agencies can be followed, but many offer inadequate protection from chemicals, the institute claims.
“The philosophy of our program is, whenever possible, rather than looking at engineering control or personal protective equipment, we encourage businesses to look at the source and to try to eliminate the use of that chemical upfront. Because if you eliminate the chemical, then you don’t have to worry about controlling exposure,” said Rachel Massey, policy program manager and senior associate director at TURI.
Castranova seconded that opinion. “The best treatment is removal of the exposure agent,” he said. “Let’s say the person has allergic asthma and is allergic to one particular thing. That one particular thing occurs in Step 7 of a process. That person could be transferred to a step where there’s no exposure. The preference is if the exposure can be decreased, the preference is to decrease it by industrial hygiene processes.”
In its report about the manager’s death, Michigan FACE’s recommendations for employers who spray isocyanate-containing materials include providing a ventilated room and checking ventilation effectiveness, implementing a written hazard communication program, performing a workplace hazard assessment, and implementing medical monitoring of workers exposed to asthma-causing agents.
The National Heart, Lung, and Blood Institute shares the following guidelines for employers to help prevent occupational asthma among workers:
- Follow federal safety guidelines.
- Implement programs that limit exposure to allergens and irritants by eliminating or substituting them.
- Create a surveillance program to identify exposed workers. Spirometry and skin tests can aid in detecting the disease.
- Educate workers about workplace hazards.
- Ban smoking.
A 2010 report from UMass Lowell and the Asthma Regional Council of New England outlines three strategies employers can use to “reduce the burden of asthma among employees and their dependents.” Hoppin and her colleagues developed the strategies after interviewing 15 employers and reviewing more than 90 studies. The strategies are:
- Ensure worker health benefits agree with recommended best practices for managing asthma – such as reimbursements for assessing lung function and symptoms – and lower costs.
- Bolster health promotion programs to help workers manage asthma.
- Make sure common asthma triggers are eliminated and chemicals linked to asthma are limited in work environments.
Typically, employers address asthma in one way or another, but they rarely recognize the importance of all three strategies, Hoppin said. The first and third strategies are the most important, she added.
“We really do know how to intervene and improve conditions that initiate or exacerbate asthma, in contrast to some other chronic diseases that are more difficult to manage,” Hoppin said. “Asthma is the leading work-related respiratory disease, and there are long-term consequences. For example, it might go on to become chronic obstructive pulmonary disease. Yet, there is a gap between what we know can be done to address asthma and what is done. Both need and opportunity are the reasons why it’s important for employers to address it.”