Sick at Work?

For some workers, various symptoms of illness appear when they enter the workplace and disappear when they leave. These workers suffer from sick building syndrome (SBS).

According to the U.S. Environmental Protection Agency (EPA), SBS is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. The complaints can be localized in a particular room or zone, or they can be widespread throughout the building. In contrast, the term building related illness (BRI) is used when symptoms of diagnosable illness are identified and can be attributed directly to airborne building contaminants.

Often the factors contributing to SBS are temporary, but some buildings have chronic problems. Frequently problems result when a building is operated or maintained in a manner that is inconsistent with its original design or prescribed operating procedures.

SBS or BRI?

EPA lists indicators that can help you determine if health problems are related to SBS or BRI. SBS may be the culprit if:

• Building occupants complain of symptoms associated with acute discomfort, such as headache; eye, nose, or throat irritation; dry cough; dry or itchy skin; dizziness and nausea; difficulty in concentrating; fatigue; and sensitivity to odors.
• The cause of the symptoms is not known.
• Most of the complainants report relief soon after leaving the building.

BRI indicators include:

• Building occupants complain of symptoms such as cough; chest tightness; fever; chills, and muscle aches.
• The symptoms can be clinically defined and have clearly identifiable causes.
• Complainants may require prolonged recovery times after leaving the building.

Although any of these complaints can result from other causes, studies show that symptoms may be caused or exacerbated by poor indoor air quality.

What Makes a Building Sick?

The EPA's list of reasons buildings are sick includes inadequate ventilation, chemical contaminants from indoor sources, chemical contaminants from outdoor sources, and biological contaminants.

In the early and mid-1900s, building ventilation standards called for approximately 15 cubic feet per minute (CFM) of outside air for each building occupant, primarily to dilute and remove body odors. Energy conservation measures that resulted from the 1978 oil embargo reduced that requirement to 5 CFM per occupant. In many buildings, this rate was found to be inadequate to maintain the health and comfort of occupants. Consequently, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) revised its standards to provide a minimum of 15 CFM of outdoor air per person (20 CFM per person in office spaces). Up to 60 CFM per person may be required in some spaces, such as smoking lounges, depending on the activities that normally occur.

Chemical contaminants from both indoor and outdoor sources cause or contribute to sick building syndrome. Indoor sources include adhesives, carpeting, upholstery, manufactured wood products, copy machines, pesticides, and cleaning agents that can emit volatile organic compounds (VOCs), including formaldehyde. Tobacco smoke releases high levels of VOCs, other toxic compounds, and respirable particulate matter.

VOCs have been proven to cause chronic and acute health effects at high concentrations, and some are known carcinogens. Lower levels of multiple VOCs may also produce acute reactions.

Combustion byproducts such as carbon monoxide, nitrogen dioxide, as well as respirable particles can come from unvented kerosene and gas space heaters, woodstoves, fireplaces, and gas stoves.

Chemical contaminants from outdoor sources can enter a building through air intake vents, windows, and other openings.

Biological contaminants found in buildings include bacteria, molds, pollen, and viruses that may breed in stagnant water that has accumulated in ducts, humidifiers, and drain pans or where water has collected on ceiling tiles, carpeting, or insulation. Insects or bird droppings can also be a source of biological contaminants.

Symptoms related to biological contamination include cough, chest tightness, fever, chills, muscle aches, and allergic responses such as mucous membrane irritation and upper respiratory congestion.

The Facts About Mold

Of the biological contaminants listed, mold receives the most attention these days. Home sellers are being asked to provide mold inspection reports before selling, and thousands of mold-related insurance claims are unresolved. So how dangerous is mold?

Some molds produce toxic substances called mycotoxins. According to the American Industrial Hygiene Association's publication The Facts About Mold, airborne mycotoxins have not been shown to cause health problems in residential or commercial buildings. The health effects of breathing mycotoxins are not well-understood and are currently under study. More is known about the health effects of consuming moldy foods or feed containing mycotoxins than about the effects of breathing mycotoxins.

Black mold or toxic black mold usually is associated with Stachybotrys chartarum, a type of greenish-black mold commonly associated with heavy water damage. Not all molds that appear to be black are Stachybotrys. The health effects from exposure to this type of mold are similar to those from other common molds, but have been inconclusively associated with more severe health effects in some people.

A small amount of mold growth is not a major concern, but no mold should be allowed to grow and multiply indoors. Large quantities may cause nuisance odors and health problems for some people. Mold also can damage building materials, finishes, and furnishings.

Most people have no reaction when exposed to molds. For mold-sensitive individuals, the most common health effects are allergic reactions similar to common pollen or animal allergies. Flulike symptoms and skin rash may occur. Molds also may aggravate asthma. In rare cases, fungal infections from building-associated molds may occur in people with serious immune disease. Most symptoms are temporary and eliminated by correcting the mold problem.

Steps to a Well Building

If worker complaints indicate a possible sick building, what should you do? First investigate to determine whether a complaint actually is related to indoor air quality. Document as much as you can about the complaint and suspect HVAC zones.

Next, identify the cause of the complaint. Finally, determine the most appropriate corrective actions. Recommended solutions include combinations of the following:

1. Remove or modify pollutant sources. Perform routine maintenance of HVAC systems; replace water-stained ceiling tile and carpeting; enact smoking restrictions; vent contaminant source emissions to the outdoors; store and use paints, adhesives, solvents, and pesticides in well-ventilated areas and use these pollutant sources during periods of nonoccupancy; and allow time for building materials in new or remodeled areas to off-gas pollutants before occupancy.
2. Increase ventilation rates and air distribution.
3. Use air cleaners. Note that air cleaners can be useful but have limited application. Don't rely on them to correct all problems caused by poor air quality.
4. Educate and communicate. When building occupants, management, and maintenance personnel fully communicate and understand the causes and consequences of problems, they can work more effectively together to solve and prevent them.