Sooner or later, the appearance of mold on concrete structures, including kilns, production buildings, and even offices, will likely warrant investigation. Mold is a generic name encompassing many common fungal organisms that can be found in virtually all buildings: only when it becomes prevalent in larger colonies does a problem arise. Thriving in moist and warm areas, mold is found commonly along coastal regions and among forest detritus. In the workplace, the concrete walls of curing kilns are conducive to its growth. Discoloration of the concrete or paint on these walls or nearby surfaces is usually an indication of the presence of mold colonies.

Additionally, mold flourishes in areas where a leaky pipe or roof provides recurring moisture, as in an attic or down a wall. Evaporative coolers can also foster mold growth. Following is an itemized list of office mold generators:

• HVAC systems that cycle off during nonoccupancy hours create fluctuations in temperature and humidity;
• Undersized and oversized HVAC systems can contribute to inadequate moisture control;
• Roof leaks, plumbing leaks, and sewer back-ups constitute water-intrusion sources;
• Properties located in the flood plain that lack sump pumps, moisture barriers, and exterior grading may be susceptible; and,
• Interior moisture sources include indoor pools, spas, basements, and laundries that do not have HVAC systems designed to remove the extra moisture.

Mold becomes a concern when it can be detected by sight or smell, especially when an employee believes mold exposure in the workplace is causing him or her discomfort or illness. Exposure to mold in the workplace usually involves inhaling airborne mold spores and/or mycotoxins. Just as susceptibility to mold toxins varies among individuals, the toxicity of mold varies widely among its many species. Though rare, molds that produce mycotoxins are the ones that generate the “sick office syndrome.” Allergies to mold, however, are common.

MOLD & FUNGI SPECIES	HEALTH IMPACT	WHERE FOUND
Alternaria	Asthma Eye infections	Aging plants Cellulose tiles and wallpaper
Aspergillus (fumigatus, flavus, and niger)	Severe allergic lung disease	Decaying leaves Damp lining of HVAC systems Warm environments
Cladosporium	Common allergenic responses	Where freestanding water is present Tile grout, bathroom sealants Ceiling with condensed water from piping
Penicillium	Fungal infections	Cold temperatures Refrigerated food spoilage Common in air
Mucor	Rarely pathogenic Systemic infections	Grows on sugar and starches
Cryptococcus neoformans	Infections Can progress to meningitis Difficult for AIDS patients	Pigeon and chicken droppings Guano fertilizer
Histoplasma capsullatum	Infections TB-like lung disease	Soil containing bird and bat droppings
Stachybotrys chartarum	Debatable health effects Fatigue, rashes, headache, nausea, coughing, diarrhea	Damp cellulose materials Greenish-black appearance Water-damaged areas
Source: Daniel P. Mahoney and Jerome E. Spear, “Mold Risk Assessment & Remediation,” Professional Safety, Aug. 2003, p. 21.

The dreaded “toxic black mold” is notorious for being impossible to eradicate, and houses contaminated with the mold must be abandoned. Fortunately, this is not a common occurrence. Usually mold presents a serious health problem only to susceptible persons or those allergic to mold. The official toxic black mold is either Stachybotris chartarum or Stachybotris atra, commonly referred to simply as Stachybotris (pronounced stack-e-boat-ris). A number of additional varieties have now acquired this designation, including several species in the genera Stachybotris, Aspergillus, and Penicillium. The accompanying table lists these and other common indoor molds with their attendant health hazards.

The low-tech solution to a perceived mold problem is to thoroughly investigate the building, looking for discoloration, leaks, and similar places where mold is likely to occur, as identified above. If mold is detected, a 25 percent solution of bleach and water applied with a garden sprayer will usually kill it. Interior surfaces can be washed using a sponge dipped in this same bleach solution. Other chemicals commonly found on the market also work well: Jomax is mixed with water and sprayed in one or two applications; Kilz is a brand of interior wall primer commonly used to minimize the recurring growth of an infestation of office mold after the mold has been killed. Both products can be found in building centers, lumberyard outlets, and paint stores. Periodic and regular change of air conditioning filters is also recommended. When mold occasionally grows in ventilation systems, a professional duct-cleaning service can eliminate or minimize the problem. A lasting remedy, of course, requires eliminating the source of the moisture. To control mold growth on concrete-curing kiln surfaces, regular (e.g., monthly) spraying can be effective.

The high tech — and expensive — solution is to call in a specialist who conducts an array of tests for the detection of mold. These tests include bulk sampling, tape, swab and contact plates, or bio-aerosol sampling. Identifying the particular type of mold spores is yet another science, requiring an additional specialist to analyze the samples. Unless symptomatic problems or claims are an issue, it may be sufficient to simply identify if mold is present or not. Elimination of the mold, then, would involve the same procedures specified for the low-tech solution, providing the mold is not one of the more toxic species.

In seriously contaminated areas where mold can not be eliminated by the simple solution outlined above, the following steps are recommended:

• Contract a remediation company to evaluate the site, develop a remediation plan, and provide a cost estimate. It is not uncommon for the treatment to be repeated several times to eliminate the problem.
• Contain the work area.
• Remove porous and semiporous materials that are water-damaged or contain microbial growth.
• Scrape or otherwise remove surface microbial growth or heavily contaminated areas.
• Dehumidify the area during treatment and maintain humidity at 60 percent or less after treatment.
• Employ specialists to HEPA vacuum.
• Conduct clearance inspections and sampling to verify the mold is contained.

A high-tech approach offers more accuracy in diagnosis and treatment, plus the clearance inspections verify the elimination of the mold or its continuing presence. Once mold has been measured (sampled) and established (reported) as a problem, however, management is legally responsible for remediation and proving that safe working conditions have been restored.

Personal protection equipment used by remediation personnel includes N95 particulate respirators, gloves and eye protection for small projects. Large or extremely toxic projects can require a full-face HEPA particulate respirator, gloves, disposable full-body clothing with headgear and foot coverings.

Mold can usually be managed inexpensively using the low-tech solution outlined above. Although mold constitutes a new exposure hazard, following some simple directions will usually take care of the problem quite adequately.

FEDS WEIGH IN ON MOLD

OSHA continues to seek support and direction for a mold standard, although the American Conference of Governmental Industrial Hygienists (ACGIH) as well as other sources and documented literature define which molds are toxic and their relative levels of toxicity. Despite a tendency to wait and see what OSHA will do, some states are presently considering mold legislation.

Similarly eyeing this regulatory gap, EPA has published guidelines titled “Mold Remediation in Schools and Commercial Buildings.” EPA contends that mold exposure creates indoor air pollution and, therefore, should come under its regulatory jurisdiction, although normally it regulates only exterior air pollution. The previous divergence of regulatory jurisdictions left indoor air quality issues affecting worker safety to OSHA and outdoor pollution mandates to EPA. (Nevertheless, EPA did get a big bite into the asbestos regulations.)

The New York City Department of Public Health (NYCDH) published “Guidelines on Assessment and Remediation of Fungi in Indoor Environments,” citing ASHRAE 55-1992. A possible precursor to future OSHA or EPA regulations, the NYCDH guidelines define the potential degree of risk and suggest cleanup methods depending on contamination levels, including such specifics as humidity-level maintenance for contaminated structures. The Minnesota Department of Health has similarly issued guidelines for the investigation and remediation of mold in public schools.

The American Society of Safety Engineers (ASSE) announced in September that it would develop a standard targeting the protection of workers when dealing with mold remediation. The purpose of the standard is to establish minimum requirements and recommended procedures for implementation by employers to minimize employee exposure to mold. The proposed standard will not, however, establish an exposure level or action level for identification purposes or trigger remediation activities.