Is It Safe in Here?

By Pat Agnew

WASHINGTON, DC, January 23, 2001 (ENS) - Dirty air makes headlines - if it is outside where you can see it. You cannot see the air inside your house, office or school, but its quality may be an invisible health hazard, causing symptoms you are blaming on some other factor.

This does not mean that you need to grab the tent and head for the back yard. It means arm yourself with information about how the air quality inside your home can endanger your health. Learn how the construction, amenities, location and maintenance of your home, school or office building impact interior air quality. With knowledge, you can take control.


Lakewood, Colorado home (Photo courtesy National Renewable Energy Lab)
Environmental Protection Agency (EPA) studies of human exposure to air pollutants indicate that indoor air levels of many pollutants may be two to five times higher than outdoor levels. These levels of indoor air pollutants are of concern because it is estimated that most people spend as much as 90 percent of their time indoors.

Molds growing inside American homes, schools and offices can be a particular problem in wet weather. Mold can be black, gray, brown, green or reddish. Any stain appearing in damp area is suspect. Not all molds are toxic, but even common molds can reach toxic levels. Some molds produce airborne toxins, called mycotoxins.

According to a report from the Government Accounting Office, the investigative arm of the U.S. Congress, 20 percent of the America's 80,000 public schools have indoor air quality problems. Microbiological contaminants - particularly molds - account for half of indoor air health complaints. That means as many as 7,500 public schools have indoor air problems related to mold.

Molds can start growing any time water leaks, and schools, many of which have flat roofs that collect water, are notorious for leaks. Chronic leaks can turn ceiling tiles, wallboard or wood into ready-to-eat mold food. Students and teachers at Hunter Elementary School in Raleigh, North Carolina are struggling with those problems right now. Wake County school officials said Friday that they cannot definitely link the building to teachers' and students' health concerns, but they are taking steps to identify and solve the problem.

Early in the year 2000, television viewers were treated to the horror story of how mold left a new million dollar mansion fit only for the wrecking ball and wrecked the lives of its occupants.

The problem was Stachybotrys, a greenish-black fungus that can grow where moisture from leaks had provided an ideal environment. It grows on building material with a high cellulose content and a low nitrogen content such as gypsum board or fiber board, in areas with relative humidity above 55 percent.


Stachybotrys mold growing on a sponge (Photo courtesy Tenants of the Fairways, Sacramento, California)
People with chronic exposure to the toxin produced by Stachybotrys reported cold and flu symptoms, sore throats, diarrhea, headaches, fatigue, dermatitis, intermittent local hair loss, and generalized malaise. The toxins produced by Stachybotrys will suppress the immune system affecting the lymphoid tissue and the bone marrow. The mycotoxin is also reported to be a liver and kidney carcinogen.

In October 1999, Department of Allergy, Asthma, and Immunology, Children's Mercy Hospital, Kansas City, Missouri reported the case of an infant with a lung hemorrhage whose residential environmental assessment revealed the presence of the toxic mold Stachybotrys. Other hospitals around the country have dealt with similar cases of infants with bleeding lungs who recover in the hospital but become ill again after returning home.

The homes of a group of affected babies in Cleveland had experienced major flooding the previous year and experts eventually uncovered Stachybotrys flourishing in air return systems or basement crawl spaces.

Health problems caused by other molds range from coughing and headaches to chronic fatigue, memory impairment and loss of balance.

Molds can be handled by controlling moisture inside the building. If a pipe leaks, you may be angry with the plumber who fixed it last week and did not get it right, but do not leave it dripping until he comes back. Shut off the water in that area and begin drying out the wallboard, the cabinet or the carpet which has been saturated.

This is no time for deferred maintenance. According to the EPA Indoor Environments Division you may have only 24 to 48 hours before mold starts to grow. There are molds that can grow on wood, paper or carpet. Moisture makes the growth possible.


A house under construction near Chicago (Photo courtesy National Renewable Energy Lab)
The law firm of Edward H. Cross & Associates of Santa Ana, California specializes in indoor environmental law, particularly in representing people who have been made ill due to poor indoor air quality. "People often fail to realize that mold growth is often due to the negligence of a landlord, homeowner’s association, builder or other party," these lawyers state on their website. They point out that water damage may be the result of defective plumbing, construction defect, flooding from a city sewer system, or negligent maintenance by a landlord.

Stachybotrys are common in the western states. Berlin Nelson, a professor at North Dakota State University and a member of the American Phytopathological Society, says, "Over the past 20 years in North America, evidence has accumulated implicating this fungus as a serious problem in water damaged homes and buildings."

Spores of the Stachybotrys fungus are in soil and are introduced along with flood waters or dust and dirt entering a building. The fungus is most common on the paper covering of sheetrock but can also be found on wallpaper, ceiling tiles, paper products, carpets with natural fibers, paper covering on insulated pipes, insulation material, on wood, and on general organic debris.

"Because leaks can occur behind walls and in covered ceiling areas, the fungus may grow profusely, but not be readily visible," says Nelson. When seen, the fungus generally has a black appearance and will be slightly shiny if wet, a powdery appearance if dry.

Nelson advises that people should not attempt to solve the problem without following recommended safety procedures for working with toxic molds. Get advice and help, he says. "Disinfecting the surface of contaminated materials, a common reaction to molds, may kill the fungus on the surface, but fungal growth within the substrate will often survive and grow again," says Nelson.

Correct the moisture problem to prevent further mold development. Roof leaks are another cause of mold growth. Flat roofs are particularly vulnerable to leaks, but all roofs need to be checked regularly.

Radon is another sneaky stalker. An odorless, colorless gas derived from the radioactive breakdown of uranium products, radon is the second leading cause of lung cancer in the United States. It is detectable only by testing.


Digital radon detector (Photo courtesy Safe Home Products)
It occurs naturally in some soils and in some well water. If homes have been built where fill from a uranium processing operation has been used, radon gas may be a problem.

All homes should be tested for radon, except residences above the second floor in multi-level buildings, according to the Surgeon General, the Environmental Protection Agency, the American Lung Association, and the American Medical Association. It is also recommended, though not required by law, that schools and daycare centers test for radon.

Testing is quick and inexpensive and remediation may be financed through a mortgage. Radon detection kits are relatively inexpensive, starting at about $25, and simple to use. They are readily available in hardware, grocery and department stores. Once the test is completed, the homeowner mails the device back to the manufacturer for analysis.

There are two basic methods of reducing indoor radon. The first is sealing cracks and other pathways through which radon can enter. This may involve covering exposed areas of earth in basements, storage areas, drains, and crawl spaces with impermeable materials like plastic sheet metal, and sealing cracks and openings with mortar or urethane foam.

The other method of reducing indoor radon is increasing ventilation so that the radon gas is forced out of the building.

Most homes will not have a radon problem. The EPA has mapped the nationwide distribution.

Building materials used in your home, office or school may affect the indoor air quality. Asbestos and asbestos containing materials have long been in the public eye as offenders.

These recently made headlines again when the Public Health Service asked the National Institute of Occupational Safety and Health to look into the health hazards for workers and homeowners handling insulation produced by the W.R. Grace & Co. vermiculite mine in Libby, Montana.

Made from ore heated until it pops like popcorn, the insulation, marketed as Zonolite, was used in an estimated 2.5 to 16 million homes. The mine operated from 1963 to 1990. The investigation is continuing.

Asbestos and materials that contain it, such as pipe and furnace insulation, shingles, millboard, textured paints, other coating materials and floor tiles, are usually found in older homes.


Asbestos pipe and boiler insulation does not present a hazard unless the protective canvas covering is cut or damaged so that the asbestos underneath is exposed to air.
The EPA's advice if you suspect your home contains asbestos is do not panic, and leave it alone. Do not rip it, saw it, sand it or try to remove it. The danger from asbestos is airborne fibers which lodge in the lungs. Undisturbed asbestos and asbestos products that are not deteriorating do not release these fibers into the air.

If you are planning to remodel your home, or do anything that will disturb asbestos, you must have it removed by a professional and disposed of properly.

There are no immediate symptoms from asbestos exposure, but there is the long term risk of chest and abdominal cancers and lung diseases.

New homes will not have materials containing asbestos, but emissions of formaldehyde may occur from the extensive use of pressed wood products containing urea formaldehyde (UF) resins. They include particleboard used in subfloors, cabinets and furniture and decorative hardwood, plywood paneling used in cabinets and furniture.

Formaldehyde is a colorless, pungent gas, which can cause nausea, watery eyes or burning sensations in the eyes, nose and throat. Some people have difficulty breathing and high concentrations may trigger attacks in asthma sufferers.

Medium density fiberboard used for drawer fronts, cabinets and furniture tops, contains the highest resin to wood ratio of any UF pressed wood product and is generally recognized as the highest formaldehyde emitting pressed wood product.


Home under construction, as part of the Building America Program in Highlands Ranch, Colorado (Photo courtesy National Renewable Energy Lab)
If you are building a home, you may have some control over the materials used. In that case, choose softwood plywood and flake or oriented strandboard, which are produced for exterior construction and contain the dark, or red black phenol formaldehyde (PF). Woods that contain PF resin emit formaldehyde at lower rates than those containing UF resin. Exterior grade construction materials are usually rougher in appearance than interior grade.

If you live in a prefabricated or mobile home built since 1985, there is no need to worry about the emission of pollutants from construction materials. Since 1985, the Department of Housing and Urban Development (HUD) has permitted only the use of plywood and particleboard that conform to specific emission limits in the construction of manufactured homes.

Carpet and drapes can also emit formaldehyde, since one of its many uses is to provide a permanent press finish.

When materials are new, high temperature and humidity can increase the release of formaldehyde. If you have added materials which give off formaldehyde, increase the ventilation of your home and use air conditioners and dehumidifiers to keep temperatures moderate and reduce humidity.

During the 1970s, many homeowners had urea formaldehyde foam insulation (UFFI) installed in the wall cavities of their homes as an energy conservation measure. High indoor concentrations of formaldehyde were found in some homes soon after the UFFI installations. Few homes are now being insulated with this product, and if the insulation was installed many years ago, there should no longer be high levels of formaldehyde in the air. Emissions from all formaldehyde containing materials diminish over time.

Homeowners have more control over furnaces and air conditioners, which regulate air quality, temperature and humidity. Keep them clean and in top working order in order to minimize pollutants in your building. If they require filters, use the best quality.

Do not make the mistake of keeping your windows too tightly closed. In this age of caulking every crack for energy efficiency, homes may not get enough outside air to be healthy.

Carbon monoxide is a colorless, odorless gas produced by burning any fuel. The initial symptoms of carbon monoxide poisoning are similar to the flu, and include headache, fatigue, shortness of breath, nausea and dizziness. Exposure to high levels of carbon monoxide can cause death.

After a recent rash of carbon monoxide poisonings, including incidents in Maryland, Pennsylvania and New Jersey, the U.S. Consumer Product Safety Commission (CPSC) is repeating its recommendation that every home should have a carbon monoxide alarm. Good carbon monoxide monitors are not expensive.

CPSC also urges consumers to have a professional inspection of all fuel burning appliances - furnaces, gas stoves, fireplaces, clothes dryers, water heaters, and space heaters - to detect potentially deadly carbon monoxide leaks.

Gas operated appliances need to be checked for carbon monoxide emissions. Good carbon monoxide monitors are not expensive.

Investigate the location of your home and do it before you purchase. Historically, many dumps were filled in and houses built on them. Garbage dumps were treated differently years ago. No one paid attention to what was discarded, nor were the dangers of certain fill materials recognized. Toxins from both air and soil can enter homes, schools or offices built on such sites. Municipal agencies and long time residents are good sources of information about the historic use of land.

Arm yourself with information to be sure that your home, school or office is safe and stays that way.

The EPA offers extensive information at:

Find out more from the American Lung Association of Minnesota, at:

Information on dealing with molds can be found at Indoor Air Solutions, Inc.

The Consumer Product Safety Commission has valuable information at: