Carpets in Schools?


Carpets have qualities that we like to live with, such as sound dampening, slip prevention and just a softer place to sit on the floor. In lower elementary grades sitting on the floor is part of most days.

It seemed like a good idea at the time.For many years a quick and inexpensive solution to school flooring was to install carpeting. It seemed like a good idea at the time. Years later, after many children and staff had suffered from complications arising from carpet use, most school boards in Nova Scotia removed carpeting from their schools and placed little carpeting, if any, in new schools. It was realized that carpets create some significant health consequences. At the time, these included: off gassing of toxic materials used mostly in the underlays and glues; from cleaning chemicals that contained hazardous ingredients; from moisture retention creating mold growth; from the sink effect gathering and later releasing dust, bacteria, pesticides and more into the breathing space; and from the fact that schools (with limited budgets) were perhaps not the best places to install finishes that needed diligent cleaning and maintenance.

So carpets were removed from schools. Although the acoustic qualities and “soft”, welcoming feeling of carpets were missed, building users reported gratitude for fewer health symptoms and generally cleaner environments, and maintenance managers reported easier and more thorough cleaning with hard flooring.

Over the past several years, the carpet industry has taken on the challenge of improving their products and overcoming some of the problems. A green label program was developed to help consumers identify carpets that had less-toxic materials, glues and underlays. In some cases completely new concepts in soft surface flooring have been developed. Some “soft flooring” is similar to VCT hard tiles, but with carpet fibres embedded in the tiles. The low pile minimizes the “sink” effect and there is no organic backing or glues for molds to feed on. Unlike “broadloom” carpet, the modular features allow worn or stained “tiles” to be replaced with minimal cost or disruption.

Some of the problems have been solved, but some remain.Does this mean that carpet is now a perfect solution for broad use in schools? Not necessarily. Some of the problems have been solved, but some remain. Some improvements depend heavily on thorough cleaning protocols, and in some cases, like the addition of toxic antimicrobial chemicals used to inhibit mold growth, there is concern that new challenges have been added in the attempt to avoid the old ones.

Let’s look first at Carpet Manufacturing Chemicals:

People became ill from living, working, or going to school in rooms containing carpet chemicals.In the past, carpets, glues and underlays had been found to be a source of airborne toxins called Volatile Organic Compounds (VOCs). Although the highest concentration of carpet chemicals off-gas in the first months, some continue for years (Rogers, Tired or Toxic). The U.S. EPA found 4-PC (4-phenylcyclohexene glue) to be the culprit in their office building that made so many people sick. It was not the only toxic chemical in carpeting, either. There were hundreds, including toluene, xylene, benzenes, phthalates, methacrylate tetracloroethylene, methyl naphthalene, styrene, and others, many of which are known carcinogens, can cause liver and kidney damage, respiratory and eye irritation, fatigue, headaches, tremors, nausea, vomiting, loss of concentration, and more. There were scientific reports of carpet installers dying of higher rates of lung cancer, and having unusual respiratory and neurological problems. There were many accounts of this health phenomenon in research and in the lay press. People became ill from living, working, or going to school in rooms containing carpet chemicals. Some never recovered their previous level of health.

Today, formaldehyde and 4-PC have not been used in carpeting for several years, and huge efforts have gone into eliminating the use of harmful chemicals. The carpet industry’s Green Label Program is helping consumers identify superior products. The industry should be congratulated for recognizing difficulties and working to overcome them. With some exceptions, the carpet industry has taken the responsible road, and there are some low-emission carpets that compare very well with low-emission hard flooring.

Carpets as “Sinks”

…carpet can become dramatic reservoir of toxic pollution – much of that tracked in from outdoorsUnfortunately, the manufacturing chemicals are only one issue. There is conflicting evidence about health issues caused by the characteristic “sink effect” of carpet structure. The sink effect refers to a trapping and settling in of particles, dirt, bacteria, viruses, molds, chemical residues, and more.

Researchers at a convention on indoor air pollution claimed that carpet can become “a dramatic reservoir of toxic pollution – much of that tracked in from outdoors.” Tests in some homes found lead levels in dust vacuumed from carpets to be “very high”. Other toxins found were chlordane, heptachlor, dieldrin, and DDT. (Interviewed homeowners claimed never to have used these substances.) The researchers also reported that carpets held 100 times more toxic debris than did smooth flooring. (Science News, August 1, 1990.)

Other research showed that volatiles gassing off from other sources in a room are absorbed and gassed off again by the carpets. One research study measured up to 900 pp cubic metre TVOCs in a carpet prior to installation, but 56,000 pp cubic metre in the same carpet after completion of the newly finished building. The increase in TVOC levels was directly attributed to the gassing off of other building materials. (Healthy Homes Consulting)

One thing everyone agrees on, however, is the importance of keeping carpets clean.Some industry researchers report no difference and in some cases higher performance of clean carpet over clean hard flooring. One study cited by the carpet industry showed that walking over dusty hard floors stirred more dust into the breathing space than did walking over dusty carpet ( But other researchers report as much as ten times the breathable dust in the air of carpeted rooms, even if the carpets are clean, as compared to rooms with hard surface floors. (Chemical Sensitivity, W.J.Rea, Vol 4, CRC Press, Lewis Publishers, Boca Raton, 1997.) In schools these particles include fine chalk dust, which is, among other things, a lung irritant to those with respiratory conditions. It can be hard to sort out the differing claims.

Interestingly, some in the industry are still citing this sink effect as a positive, air-cleaning feature. Other professionals and researchers disagree on this point. While keeping the “sink” clean by thorough and frequent cleaning may be beneficial, no reputable air filtration professional would ever recommend installation of carpets as an air filter! Meanwhile, other carpet manufacturers acknowledge the negative characteristics of the “sink” and design carpets with low pile that can’t trap as much dirt. One thing everyone agrees on, however, is the importance of keeping carpets clean.

Frequent, Thorough Cleaning is Imperative

Floor cleanliness is important for both hard surfaces and carpeting. The carpet industry recommends that carpets be cleaned as often and as well as hard floors. In homes, they recommend vacuuming “at least twice weekly and shampooing at least every 12 to 18 months, ventilating the area with fresh air during, and at least 24 hours after” (The Canadian Carpet Institute). The traffic in schools is very much higher than in most homes, so the maintenance schedule calls for daily vacuuming and more frequent cleaning. They advise using a HEPA vacuum filter to prevent respirable particles from entering the breathing space. (See CASLE’s article on filtration on our website The industry has a Green Label Program for vacuum cleaner quality as well.)

Carpet Maintenance Chemicals

Peer reviewed research shows that exposures to common airborne household chemicals can cause changes in cognitive functioning/attention/learning ability, mood/emotion, behaviour, and more. (Molhave, Otto, Lorig, etc.) As with the carpet industry, some companies are developing safer cleaning products. There are many less-toxic and scent-free cleaners available. Take caution with those that claim to be “natural” or “environmentally safe”. For example, cleaners containing citrus can claim to be “natural,” however, d’limonene, a known sensitizer, is the active ingredient. The U.S. Department of Health reports that d’limonene can be more toxic than toluene. A helpful site for obtaining chemical information is Canada’s EcoLogo program, operated by Underwriters Laboratories, Envirodesic, and Green Seal are third party evaluation programs that help identify less toxic cleaning materials.

Carpets and Mold

industry fact sheets point out that the antimicrobials only work if the carpets are cleanIn the absence of moisture, mold cannot grow. Spills must be cleaned and dried within 24 hours to prevent mold growth. It is important to keep relative humidity low in carpeted areas, and dew point/condensation needs to be controlled. It is more difficult to keep carpets dry than hard surface floors. Imagine the carpeted halls of some schools – they are wet by children’s boots at 9 AM, after recess, and again after lunch, five days a week.

Building leaks are another frequent problem in many schools. Also, carpets laid on concrete basement floors are notoriously difficult to keep dry and mold free. Some school districts have a policy against the use of carpeting in basement classrooms. The industry advises using dry or steam cleaners, and wisely uses the slogan “Carpets: Clean and Dry”.

The threat of mold growth has led to the use of mold inhibiting chemicals. These can pose a serious health hazard in their own right. Some are added to carpets during the manufacturing process, and there is research showing serious harm from their use. (Effects of renovation measures on the health status of persons exposed to pyrethroids through carpets and flooring. Boge K.P., Brokof H. et. al., Dec. 1996.) There are different antimicrobial products in use, but one article actually proposes introducing a powdered pesticide into carpets periodically to help keep dust mites down! (Hedge, Carpets in Schools Don’t Compromise Indoor Air Quality. (

Interestingly, industry fact sheets point out that the antimicrobials only work if the carpets are clean. (Technology Brief: Intersept FAQ, 01.28.02, supplied by Interface.) Once again, cleanliness is paramount.

Research Claims about the Benefits of Carpet Use

Celebrating improvements while at the same time denying there was ever a problem is illogicalAs usual, there is mixed evidence for most claims. Carpeting has been changing in recent years. Because of this, care must be taken to be sure we are not “comparing apples to oranges” when making health claims using carpet research. The materials used to manufacture carpets have generally been improved, as has awareness of the need for good carpet cleanliness. Therefore two similar studies, one done on dirty old carpets and one done on clean, new carpets, can produce quite different results.

It is also important for companies to choose carefully the research claims they tie to their products. In a search of research on industry websites, it is noticeable how some in the industry fall back on denying that the problems they themselves have tried to overcome ever existed (or still exist). They cite research showing that carpets don’t cause health problems; that schools don’t have mite problems; that asthma isn’t triggered by carpet chemicals or carpet dust; that molds are the problem not carpets; and so on. Celebrating improvements while at the same time denying there was ever a problem is illogical, but worse, it does disservice to the human beings who have had their health affected.

Along the same lines, trying to make major points with minor or partial evidence hurts credibility. An example would be the graphs and research claims found on industry sites that claim cleaning chemicals used to clean hard floors have much higher VOC content than those used for carpet maintenance. This claim depends very much on the products tested. It may be true of high-emission cleaners, but low-emission cleaners exist for both carpet and hard floors.

Some test results found carpets and carpet glues off-gas less than VCT hard flooring and their glues. VOC levels, materials, and speed of off-gassing vary from product to product, whether it is VCT flooring, glue, or carpet. Old carpets off-gas almost no VOCs, while some new carpets can off-gas heavily at first. We can easily find VCT flooring and glues that have unacceptable or acceptable off-gassing. Again, low-emission materials exist.

Yet another example is an article on a renovated school which compared pre- and post-renovation conditions including indoor air quality, attitude, comfort, parent participation, etc. There was a tendency in the article to imply that the free new carpets, training, equipment and carpet maintenance program provided by the carpet industry were the reason for the improvements, when many other improvements were made to the school, including a new ventilation system. The carpets were indeed very well maintained and therefore probably performed well, but are unlikely to be responsible for all of the benefits realized. (Charles Young Elementary School, Washington, 1997.)

Carpets and Health

we may be poisoning ourselves while trying to poison “germs” unnecessarilyThe evidence that dirty carpets and moldy carpets can trigger respiratory symptoms is easy to find in MEDLINE/PubMed and asthma searches such as the American Lung Association site ( Asthma rates are reported to decline when carpets are removed, but the carpet industry cites evidence to the contrary. The Swedish research showing asthma rates over a 40 year period continued to rise even though carpets sales dropped is an oversimplification. The data covered 1975 to 1992, a period when many other factors influencing indoor air quality were also emerging. Asthma had just been recognized as a real, not psychological, illness in the early 1970’s, and the increase in asthma diagnosis in that time period can at least be partially attributed to this new recognition. It is not clear from the information provided whether the researchers were reporting the “causing” of disease or the “triggering” of asthma symptoms. There is strong evidence that dirty carpets, moldy carpets and chemicals in new carpets trigger asthma, and that chemicals such as 4-PC found in earlier versions of carpeting did cause asthma and other illnesses, however, asthma rates have also been linked to many possible causes that are worsening rather than lessening over time. These include immunization in the U.S. (their immunization programs are more aggressive than ours in Canada), increased use of pesticides, and also “clean” homes – the unexpected result of using stronger and stronger chemicals in our homes (chlorine, disinfectants which are really pesticides, air fresheners, and many more). The indications are that we may be poisoning ourselves while trying to poison “germs” unnecessarily. So, there are many other factors influencing asthma rates. If these factors were controlled for in the Swedish study, this was not evident in the information presented. Carpeting’s role in the illness picture may be improving with low emission carpet materials and greater cleanliness in recent years, but even that remains to be seen, as there are many variables to be considered. (Carpet: Perception vs. Reality. Werner Braun, President CRI, March 21, 2003.)

Regarding the use of disinfectant cleaners, Health Canada and the U.S. Centre for Disease Control in Atlanta, among others, clearly state that regular cleaning with soap and water will remove most microbes, and other contaminants. Removing can be as effective as killing. Disinfectants (which are classified by government as pesticides) are largely overused. In schools with hard surface floors, the washing process can remove contaminants without the need for antimicrobials and other special cleaning products called for in the carpet literature. (Cleaning for Health: Products and Practices for a Safer Indoor Environment, Culver et. al, INFORM, 2002.)


The industry clearly recognizes the key to healthy carpet use is keeping them well maintained and cleaned. (“Carpet: Perception vs. Reality. Subtitle: Why cleaning and Maintenance are critical” by Werner Braun, President, the Carpet and Rug Institute, March 21, 2003.)

There are challenges to any cleaning process. For hard floors, scheduling, low-emission product choices, and training of custodians in correct dilutions, how to clean efficiently and not to re-use dirty water, are all important. These are all factors in carpet maintenance as well. The Re:Source Maintenance Guide for carpets outlines how critical daily vacuuming and spot removal and other attention to the carpet surface are to carpet performance, how good it continues to look, and how soon it will have to be replaced. Specialized maintenance instructions include pile-lifting equipment, water extraction equipment, daily HEPA vacuuming, several soil and spot removal chemicals, instructions not to walk on the newly cleaned pile because it will soil more quickly, and more. A school board will need to decide not only if it has the manpower to attend to carpet maintenance, but also if it has the resources to purchase and maintain two complete floor cleaning systems.

A school district considering use of carpets might choose to review cost effectiveness. From a labour point of view, the industry reports that carpets are less expensive to maintain than hard flooring, while independent research indicates the opposite. Custodians report that it is more time consuming to clean carpets than hard surfaces.

The industry claims that a survey of IICRC professionals determined that the maintenance of VCT hard flooring carries twice the cost of maintaining carpet per square foot. They report light traffic carpet costs at $0.5547, VCT at $1.0821. Heavy traffic carpet costs $0.6104 and VCT $1.742. However, the comparative study of carpet, terrazzo, and tile floors in an article from School Business Affairs, June 1994, reached other conclusions. Materials, installation, and maintenance (including cleaning) were compared over a forty year period. In this study it was found that over the long term, carpets cost twice as much as hard floors to keep acceptably clean, and they had to be replaced more often than either of the others. Perhaps school districts have on hand comparative information from their own experience that can clarify these differences.

This Expert vs. That Expert

A square foot of carpeting can hold tens of millions of microorganisms including bacteria and virusesSometimes it seems as if discussions are exercises in “this expert” verses “someone else’s expert”. Thad Godish, director of the Indoor Air Quality Research Laboratory at Ball State University in Muncie, Indiana, stated that carpeting has no place at all in schools. Besides being a great repository for dust, he verified that carpets support the growth of mold and dust mites. A square foot of carpeting can hold tens of millions of microorganisms including bacteria and viruses (Informed Consent, Nov/Dec 1993). Some industry sources claim dust mites (a trigger for asthma and allergies) are not an issue in school carpets. One industry article claims that mites are far worse in bedding and “we don’t recommend removal of bedding to avoid mites”.

While opposing views debate, sometimes experience is a better teacher. Acres of carpeting have now been removed from Nova Scotia schools, with obvious positive benefits. In our local elementary school, improved air quality has clearly resulted. We did not predict that the results would be so dramatic. We were prepared to see only fewer complaints from those with respiratory illness, and nothing more. However, previously sceptical individuals comment that they can tell the difference, and report feeling better too. An administrator revealed that he has asthma and that since the carpets were removed he no longer suffers from asthma at school. Even the local private piano teacher commented lately that her students no longer arrive from school with red, sniffly noses the way they used to. Is this because the carpets were hard to keep clean? Or because they were havens for mold growth in damp areas? Or were they old with fibres breaking down and contributing to air particulate? And how does this relate to the newer carpeting coming on the market?


As mentioned before, carpets have qualities we like to live with. Two of these would be sound dampening, and soft floor seating. Carpets perform well in reducing slips and falls. Textured ceramic tile works too, but there are also VCT flooring finishes that have been developed to actually be less slippery when wet than when dry. The same is true with gymnasium floor/wood floor finishes. (Elevating Floor Care to Floor Safety. Carpets can improve a room’s noise level. Wall and ceiling baffles and other design elements can also improve this. For P to 3 classrooms where children need comfortable floor seating, teachers and parents have a choice of several options including folded and stitched towel “pillows”, one or two larger, washable area rugs, or small 100% cotton washable rugs (from department stores) with non-slip patches sewn on the bottoms. One school’s PTA purchased the rugs and a washer and dryer, and parents rotate the washing routine.


schools have special characteristics that may make it hard for carpet’s improvements to succeedThe industry has worked hard to remove barriers to carpet use. It is good that industries have provided low-emission alternatives, high performance vacuums, less-toxic cleaning chemicals, low-pile (low sink) fibres, and even replaceable modular carpet “tiles”, but schools have special characteristics that may make it hard for carpet’s improvements to succeed.

It takes longer to clean a carpet than a hard floor, and this translates to worker wages. The concerns over mold growth in or around carpets result in the use of antimicrobials in carpets, which in turn bring concerns over chemical exposures. But perhaps the most significant barrier is human nature – the tendency to cut corners, put off cleaning, not notice leaks or dampness, and clean less thoroughly or less often than required for whatever reason. In the past, the consequences to health from that factor alone contributed heavily to the eventual removal of the acres of carpets from schools.

If a carpet were needed or wanted for some reason, a commitment would have to be depended upon to keep the carpets vacuumed well and frequently, and to place them in dry areas (free from condensation, spills, damp or basement floors) that remain dry or dry out completely within 24 hours, and to clean them with less toxic cleaning materials, to choose low-emission, high performance, low-pile, or even the modular carpet-tiles, and to get them without antimicrobial treatments. Is the commitment and capability present in today’s schools to clean them and maintain them to the standard needed? Overwhelmingly, even the industry tells us that the most important factors for effective, healthy carpet use are maintenance and cleanliness. Time will tell whether carpeted and non-carpeted floors serve schools equally well.