Note: This article originally appeared in Properties Magazine, June 2001 Issue, page 74.
INDOOR AIR QUALITY – MOLD
By Steven R. Pressman
A Very Unusual Year
This year has been very unusual regarding the contamination of structures with common mold. Pollen and spore counts have not been higher. In Dallas, Texas outside spore counts were measured at 50,000 particles per cubic meter. In many neighborhoods schools, commercial properties, and residences became successively contaminated with mold. Presently the Texas state legislature is considering mold regulations similar to the asbestos and lead paint regulations adopted by most states and the federal government.
Common Mold Species
Aspergillus – This is a very common mold and while exposure to it by people with normally functioning immune systems rarely results in disease at least sixteen species have been found to cause disease. However, people with allergies and/or asthma are susceptible to lung infection. The wife of a good friend had to retire in her early fifties, giving up a teaching career, due to lung infection by mold. This was caused by her putting old living room carpet down in a warm damp basement, where the mold thrived.
Penicillium – I was once asked if Penicillium was a “good mold”. I replied that, “no mold is good if your the piece of bread its growing on!”. There are about 200 species of Penicillium and only a few are used to make antibiotics. Most grows on damp carpet, wallpaper, and fiberglass duct insulation. Toxins produced by Penicillium include penicillic acid (of course), peptide nephrotoxin, and potentially, dangerous mycotoxins.
Stachybotrys – Is easily the most infamous of the common house molds, being linked to sudden infant death syndrome (SIDS), and being a source of toxic mycotoxins which were used by the Soviet army as biochemical warfare agent. This mold likes to live on moist common building materials, such as sheet rock, ceiling tiles, cellulose insulation, and wall paper. Exposure to Stachybotrys can cause nose bleeds, cold and flu like symptoms, headaches, fever, and general listlessness. Many people experience a burning sensation in the mouth and nasal passages. This mold can also cause skin rashes.
It should be kept in mind that these are just the three most common molds, usually test results will indicate eight to twenty different types of molds or fungus, of which each type may represent hundreds of species. The kinds of molds and fungus found will vary according to the ambient conditions, region of the world, and the time of year.
Testing for Mold
Presently there are two easy and reliable tests for mold the tape test, for surfaces, and the Air-O-Cell™, for the air. The tape test consists of placing cellophane tape on the suspect surface, gently removing it and placing it in a sterile container. The Air-O-Cell™ is a clear plastic air sampling cassette similar to that used to sample asbestos. Except that the Air-O-Cell™ uses an adhesive coated glass to stick particles to as the air sample is drawn in by a the sample pump. Both the tape and the Air-O-Cell™ cassettes are sent to the lab to be stained and read by microscope. The traditional method for taking mold samples, plating directly onto the growing media (or “plate”) is also still used today, but rarely. This is because molds and fungus a hardy life forms. I once sent a sample of sewage contaminated carpet to the lab, by mail from Cleveland to Dallas, in a plastic bag. Even though the carpet was cleaned twice prior to sampling and mailed away with no special care, the sample still tested positive for molds, fungus, and various other pathogens.
Immediate Protective Actions
If mold is found to be contaminating a building the first thing is to check it for visible mold growth, temperature and humidity. Roofs and condensing equipment such as refrigerators and air conditioning units should be checked for leaks. Stand pipes and the HVAC system should also be checked. Visible mold may be scrubbed with detergent and thoroughly ventilated until it is dried. Lysol or other non-chlorinated disinfectant may be used. All accessible spaces in the structure should then be cleaned and HEPA vacuumed as would be done after an asbestos release incident. This will remove the majority of mold spores from the air. I use an inexpensive air cleaning device called the Clairity Air Purifier-Ionizer to remove mold spores from the air while the contamination sources are being cleaned up.
Investigating for Sources
Once it is determined that a building is infected the source of the mold must be found. Fiber-optic bore scopes are ideal for this, but require a three eighths inch hole be drilled to use them. I bring repair materials to the site and repair the inspection holes as I go. The client’s maintenance staff then paints over the repairs which become undetectable. I also use a moisture meter to check for excess moisture in building materials, and needle probe, as well as my fingers to check for water damage. All this is necessary to detect mold growing in relatively inaccessible areas, such as, the double walls between office or residential suites.
Mold Abatement Techniques
Most mold abatement jobs are undertaken by the same professionals who work with asbestos and lead paint. A good contractor will understand the importance of complete cleanliness when preparing, or clearing an abatement site. The aggressive use of the HEPA vacuum and periodic sterilization of vacuum tools is very important to a successful abatement.
On a job I advised on recently there was only 5,000 spores per cubic meter inside the building, and 50,000 spores per cubic meter outside the building. When there is more air contamination outside the structure to be abated than inside the negative air units will be reversed to filter the air that is coming into the building, or not used at all, as appropriate. And extensive containments built of plastic sheeting become unnecessary.
Usually it is only necessary to block off the ventilation ducts and put plastic sheeting over furniture to be protected from the abatement process, especially file cabinets. Window treatments and other removable textiles are usually removed prior to treatment and sent out for cleaning. Then damaged building materials are removed.
I then recommend that the infected areas be treated using the two part Anabec System, which my company represents in the North East Ohio area. Anabec consists of a proprietary peroxide compound to kill the mold, and a residual quaternary ammonium compound to treat surfaces to prevent future surface contamination. The treatment materials are applied with an airless sprayer to walls and ceilings, and will penetrate sheet rock or plaster to a depth of one half inch. Carpets and upholstered furniture can be treated with Anabec using standard commercial grade carpet steam cleaners. Anabec contains no chlorine, which in addition to being noxious, only evaporates leaving water which promotes continued mold growth.
When treatment is completed the areas are re-tested to assure the successful abatement of the building.
Steve Pressman is the President of ANILINE ENVIRONMENTAL, a Cleveland, Ohio based provides industrial hygiene, safety, and environmental consulting firm he founded in 1988. Services offered include environmental testing, acoustic design, asbestos inspections, indoor air quality and Phase I & II Studies. The firm also publishes custom safety and environmental compliance program manuals for its clients. He holds a BA Degree from the Cleveland State University, Maxine Goodman Levine College of Urban affairs.
This page, and all contents, are Copyright © 2001 by Steven R. Pressman, Cleveland, Ohio USA.