WTC asbestos wipe sampling and cancer risk analysis, December 2001

NYC 9/11 Public Portal Document

asbestos than 1%. And it is these dusts themselves that are considered to be the ultimate hazard by EPA, even though they have levels lower than 1%. The U.S. EPA has clearly stated that levels lower than 1% could present hazards:’

Levels of 1% or less could present a risk where there is enough activity to stir up soil and cause asbestos fibers to become airborne.

The NYC DEP also exercised no oversight over building owners to insure that they did test their premises, or used a professional asbestos abatement firm for remediation.

TAKING WIPE SAMPLES OF INTERIOR SURFACES

Practicality of taking wipe samples

Taking a wipe or microvacuum sample may be the only practical way to quickly see if a building is contaminated inside, or if cleanup is complete. Air sampling is highly variable depending on the time, the exact location, the amount of activity stirring up dusts, etc. Furthermore, a large amount of specialized equipment is required. Even ifair sampling shows no detectable asbestos, there could still be a substantial reservoir in settled dusts somewhere waiting to become airborne under the right conditions. Air sampling cannot be used in lieu of a complete removal of the asbestos-contaminated dusts.

Because there will probably be a continued demand over for at least the next year, if not more, to test areas in Lower Manhattan, it might be a good time for certain individuals to learn wipe sampling techniques. Probably an individual should not take this on her/himself for only a one­ time sampling event. Even for wipe sampling, there is a fairly rigorous standardized procedure to follow with wiping methods and placing of the wipe in containers for transport, etc.

This might be an option for staff at environmental and occupational safety and health groups. Chemists, pharmacists, other scientists and health professionals might want to learn this type of sampling. The laboratory which will do the actual analysis will usually woik with the person to get her/him the right materials. There appear to be no insurmountable hurdles to setting up to provide these types of services. Workshops and training sessions could be held by various groups.

An alternative to wipe sampling is using a microvacuum to sample settled dusts. This would involve purchasing a pump designed for personal monitoring of workers imder OSHA, calibrating it, and adapting it to the sampling technique. These pumps cost from $1500 to $3000. This is a less practical option, and also does not transfer as much asbestos from surface into the sample to be tested. The detection limit also appears to be better than the microvacuum method.

Description of ASTM method D-6480-99

EPA does not have any wipe, or even microvacuum methods for asbestos. However, the American Society of Testing and Materials (ASTM) has developed method D-6480-99.'’ The required materials include particle-ffee wipe material (commonly made available for dean room supplies, called a “clean room wiper,” available from major laboratory safety supply

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