About a year ago a client brought to our attention the possibility that adhesives from self sticking tapes and labels causing health problems. Because of the experience we have had with these adhesives over the years, we decided to pull together our data and to set up a number of  tests to clarify any gray areas. From our clinical toxicology books and toxicology of commercial products books we had already found data that indicated chemicals used for these adhesives in fact quite toxic. So, for the last 16 months we have been monitoring test samples of tapes and labels to find out what happens to adhesives under various conditions. Included with our findings from controlled test samples is data accumulated from various tape performance used or analyzed during projects over the last 5 -6 years, including numerous samples collected from as far back as 35 years ago. Because so many people with extreme sensitivities are using different types of  self adhering tapes, [primarily aluminum but not limited to it], for containing toxics and to create temporary safe housing environments, this has been a major concern for us. Sensitive people tend to suffer more and have more pronounced reactions to smaller quantities of toxics. People with extreme sensitivities are not the only ones at risk, as the chemicals used in making adhesives of this kind are very prevalent in numerous household products, making regular exposure a risk for many people.

Our data includes the following sources and methods.
1. Data from our own personal in field experiences, which includes information from years of  real estate and sick building inspections, renovations, and new work in a number of different areas. Included in this data is information we have collected while working in clean room environments with self sticking tapes.
2. Data from documented, published articles in magazines and journals, Clinical Toxicology medical books, toxicology of commercial products books, etc.
3. Data from our personal client base from all over the country, primarily very chemically sensitive peoples experiences with these specific materials,
4. And data from our own private testing which focuses on various methods of containment testing under varied conditions.
Our containment vessels include glass jars and glass boxes of various sizes, metal boxes, and small rooms constructed of  inert materials, where temperature, air flow and moisture are all controlled.

In our analysis, we included a number of self sticking labels of a popular brand, several brands of duck tape, masking tapes, clear "scotch tapes", double sided tape, clear packing tape and aluminum faced tapes. Our test samples were taken from a large number of sources, not just fresh samples assembled for testing, but some duck tape, clear tape, and masking types as old as 25-30 years, and samples obtained over the last 10 years of duct work building and renovation for chemically sensitive people, especially aluminum faced types, but not limited to just these. Our fresh samples were put in a number of controlled environments, from clean glass jars and specially fabricated metal containment boxes. Contributing to our data base in this area is also all the analysis from years of work we have done on Airstream  travel trailers dating from 1954 to the 1990's, turning them into clean rooms. For the last 30 years, they have used masking  and duct tape to hang insulation and wiring in interior wall cavities. Our work has made it necessary to do containment testing of these materials, and it has shown how tapes perform over the years in various types of environments and what levels of odors are to be expected.

The toxicity of these adhesives do not diminish over the years or as the adhesive decays. In fact, in most cases, odors increase over time. Adhesives will eventually turn into dust as the backing falls apart, and this dust is still a very active toxic which can affect  people who breath it, eat it or have it absorbed through the skin. This break down takes an average [a minimum] of about 2 years for tape and possibly a lot less for self adhering labels if the conditions are right. Water will decrease the amount of time the breakdown takes, but the actual top surface tape material and it's strength will affect how much and how quickly water may penetrate to the adhesive. If it is exposed to water or humidity, it is somewhat soluble, and it can contaminate water and be redistributed on any surface the water touches. Therefore if labels are being washed off, especially on food containers, adhesives will contaminate the water, which only redistributes the toxics on any surfaces the water touches, so special procedures for total cleaning should be employed. When adhesives are fresh or gooey, they will typically be less soluble in water, but not always. Tape adhesives are quite a bit more insoluble in water, and it will take a complete dry out before they are able to absorb water or dissolve in it. But even when adhesives are strong and sticky and non absorbent, water penetration to the adhesive will increase the quantity of toxics off gassing.

Adhesive compounds used for labels and tapes are toxic from their creation. The standard list of toxics include hydrocarbon resins, styrene, isoprene, aromatic hydrocarbon solvents such as toluene, benzene, and xylenes, acrylates and acrylic resin monomers, which are the bulk of these adhesives, and they represent a whole soup of very active toxics. Reactions from these toxics can be as slight as skin, eye, respiratory irritation and headaches, to damage to liver, lungs, kidneys, convulsions and death. [Obviously there is an equation relative to quantity of exposure and sensitivity levels which determine reactions.]

They go through various stages of  life, which affect their ability to offgas toxics at a higher rate under different situations. When new or fresh, they adhere lightly to themselves and are typically more water resistant. Once exposed to air for the first time, their bonding capability is at it's peak, and most adhesives start to dry out, if not stuck to something tightly from that point on. As long as the adhesive is covered by it's top coat or layer of tape, the odors are generally minimal although some are quite strong. Remember that temperature will usually affect the amount of odor we are able to detect, with cooler temps hiding odors and warmer temps allowing toxics to outgas, and when they become exposed to air, such as when they are unwound or when the adhesive is exposed, odors become obvious.

The best aluminum type tape adhesive we have found, is used with POLYKEN  TAPE, and this has virtually no odor when new. Compared to all other types of aluminum tape, [and most other adhesives] which are seriously toxic when exposed to air, this is unquestionably the best. Other popular types have very strong smelling adhesives that create problems when back side exposure is possible, such as covering holes in air handling equipment, heat ducts and so on, which is a very common use. Since the tape is applied to the exterior surface, this leaves adhesives exposed to in duct air flow and moisture on the inside of the air system.

Scotch tapes are a bit deceptive in the same way. Initial odors may not appear to be so toxic, but as they dry out, smells change to be very odorous, especially as tape backing becomes freed of the adhesive. This happens as the adhesive turns basically to dust, but even as it does and the backing pulls away from the adhesive, the adhesive usually will not disengage completely from hard non porous surfaces. This activity is very consistent to other self sticking adhesives, and it increases the danger of exposure as the complete surface of  adhesive is exposed to the air. During this time period, as all sticking quality decreases over the next several months and longer, the adhesive is turning to dust, which easily sticks to hands and can contaminate other surfaces easily. Remember, as this dust flies around or is distributed by contaminated touch, it can become dissolved in moisture or water, which can start a whole new channel of contamination.

Another very real concern is exposure to adhesive toxics when used metal or other items are used again and again, after tape is partially pulled off. It is very difficult to remove all tape and adhesive completely. Frequently metal panels are used for containing odors from floors with carpets in temporary housing renovations, particularly in short term rentals. Because metal panels- stainless steel, aluminum and even galvanized is expensive, panels that have been taped together are frequently reused. When these panels are taken apart, tape is ripped off the old seams, leaving patches of raw adhesives exposed to the air. Although these areas may seem insignificant and small, if this is not cleaned off, it will contaminate the air. If it is allowed to decay, it can turn into dust and fly anywhere over long periods of time. Either way, it will create sub odor level toxics for extended periods of time. This scenario is common for any other applications where tape is used to stop toxics or air flow, such as around windows, on furniture, kitchen and other cabinets, other household furniture and appliances, in cars and so on. Very frequently scotch tape is used for a number of applications like this, and the results are the same. From the point where they are stuck on surfaces, they start to change and dry out, creating more odor and risk as they do.

Cleaning adhesives off surfaces is fairly difficult, as the tape backing, such as aluminum, paper or fabric types such as duck tape, need to be removed before the adhesive can be dealt with. Heat usually helps release the adhesive with the backing, but on old tape or labels with dried adhesive, this may not work. It appears that the dryer the adhesive, the more soluble it will be in water. Another words, when adhesives are wet or sticky, they are usually less soluble. Paint remover may be the best way to remove sticky adhesive when the backing is gone, such as with aluminum tape, or when the backing is weak or decayed. Dried adhesive becomes powdery which becomes airborne easily, contaminating air, skin and other surface areas. Special procedures should be set up for cleaning dried adhesives such as a scraper with a  HEPA vacuum head to gather dust as it is removed.  Porous materials can absorb odors and toxics from the adhesive, making total removal of toxics difficult, although the tape or label may initially release easier. Non porous materials tend to hold adhesives and tape longer, making release more difficult, but total cleaning  of surface areas easier, because the surface is not porous and will not absorb adhesive toxics or remover toxics. Remember that using soap and water in a bowl with most adhesives will redistribute toxics into the water, so a separate secondary wash with clean running water is required. Be sure to rinse thoroughly before any drying of the initial wash takes place. Food containers are especially critical to clean in a well regulated manner, perhaps several times to be safe.

Adhesives exposed to heat, water and moisture, even at low levels, become quite active over a relatively short period of time. Polyken tape, which has negligible odors when new, develops a milky color on the adhesive side when exposed to humidity and moisture, and the odor level becomes extremely high and is obviously toxic. We noticed that tape used on metal and glass, even thought the adhesion was tight and strong, decayed from low levels of moisture in one to several months. [Moisture in these instances was condensation formed on the inside of  closed glass jars, metal window frames, and glass windows.] So using this tape in any environment where larger quantities are possible, such as on air handling equipment and so on, are a very sizable risk because of the amount of moisture they can be exposed to. Most installers use an aluminum tape with a very active toxic on air handling equipment, which is an unfortunate choice of materials. Since in most applications, the adhesive side is exposed to the air flow through seams and joints or holes in the ducts or panels, this poses a risk to occupants who have allergies or sensitivities. In one case, we discovered  a widely distributed type aluminum tape that was used to seal seams in an air handler that had a U.V. light decontaminate fixture, which heated the tape adhesive up to the point that heavy toxics were distributed throughout the building. Even if these toxics are not strong enough to be smelled, they can have an affect on our health.

Heat can cause immediate out gassing from all types of tapes and adhesives, as with any other materials. Normally, odors are not apparent below 50 degrees. From 50 to 70, odors become obvious. From 80 on up, they become stronger and stronger. Self sticking adhesives become very active in warmer environments, and when used on heat generating appliances, they can be an immediate problem.

I feel quite strongly that any tape should never be used  for any length of time where it can be exposed to moisture or where it is not totally sealed tight and flat, on a very smooth, non porous, accepting surfaces. I try to find some other materials to use other than tape if possible. Using it in areas where it is exposed to direct sunlight on or around window areas are also high risk areas. Tape placed on porous materials may have a very short life, as it's adhesive may not hold the tape tightly for any period of time. This makes it possible for air flow to access the adhesive backing on the tape, allowing toxics to become airborne. Some of these materials are wood, cloth, concrete, certain plastics, sheet rock, wet or damp tile and metals etc.

For people with solvent sensitivities, I would avoid their use altogether, especially in locations where people spend a lot of time, or where the tapes and labels are exposed to moisture, heat or condensation. The real problem is these adhesives are dangerous, even though we may not smell their odor. We as a people are becoming aware that sub odor level toxics, which these fall into the category of, can be very dangerous and toxic whether we smell them or not. Remember that there are always a number of variable components to risk assessment and reaction analysis from toxics.

1. The quantity of toxic a person is exposed to,
2. the strength of  the particular toxics,
3. the number and types, or the combinations of toxics, [which might contribute to the severity and the compounding of reactions}
4. the length of time a person is exposed to the toxics,
5. and the variable conditions toxics are exposed to or the environment they are used in [such as heat, humidity, moisture, air exposure, circulation, confinement, and so on],
will all affect the amount, strength, and frequency of out gassing from any given toxic.

Then of course, the sensitivity level of the individual will determine whether a person may have a pronounced reaction or not.  All situations of exposure have these variables involved, and they all play a major part in determining a persons reactions. There are very few set rules from person to person regarding reactions, except in major spills of deadly toxics. But reactions from low level toxics are mostly the same in similar sensitivity level groups, whether people are aware of them or familiar with them or not. And continuous exposure to toxics of this nature, even at very low levels, from very small quantities, can bring about increased sensitivity and more serious long term health damage to these and any number of scores of other related toxics.
 

• Tad Taylor's  Healthy Homes LLC