Disaster Remediation - Is sampling necessary?
Some understandable confusion exists among insurance adjusters and property owners regarding the need to take air, water and materials samples BEFORE, DURING AND AFTER site remediation.
TESTING FOR MOLD
Leading legislative and professional bodies such as the Canada Mortgage and Housing Corporation (CMHC), the U.S. Environmental Protection Agency (EPA) and the American Industrial Hygiene Association do not normally recommend as a first step, sampling for mold - spores and propagules - in single-family dwellings and similar buildings. The recommendation is to firstly have an investigator trained in building construction and building envelope integrity check the premises for signs of water/moisture intrusion and consequent mold amplification. This can avoid unecessary expense in obtaining and analyzing samples which don't provide any useful information in the remediation process.
If, after such an inspection of the damaged premises areas of mold growth are visually identified, the scope of remediation can usually be determined at that point. Only in rare cases where medically attributable health effects are the subject of concurrent or pending litigation, would the sampling of air, surface or bulk materials be justified. Otherwise, the next step here is to remediate, using all appropriate procedures to prevent the mold becoming airborne and thus spreading to other areas of the premises.
There can be circumstances where an investigator/industrial hygienist may recommend mold air sampling because he/she couldn’t find the mold, - but suspects it may be hidden, for example behind a wall, in the attic or in the crawl space.
If the presence of mold is confirmed, the next challenge facing the insurance adjuster is to determine whether this is due to an insurable event requiring remediation, or whether it is longer-term pre-existing due to deficiencies in building envelope intergrity. One way to do this is to take viable mold air samples on culture plates and have them analysed to a higher level of identification than is possible with MCMM or spore trap samples. In this way the genera AND the species can be determined, and this additional information can often - but not always - provide a history of species growth at the contaminated site.
Air sampling per se does not of course identify the sources of mold amplification, pinpoint areas of moisture intrusion or suggest ways to remediate the problem. A thorough investigation based on building-science principles is more helpful initially than testing the air; the exception again being if there is concurrent or pending litigation involving health damage to a building occupant, which has been medically attributed to exposure to mold toxins (mycotoxins.) Other exceptions include remediation at institutional premises such as senior care homes, schools and hospitals, where health-compromised individuals can be much more susceptible to mold allergens and toxins. In these cases the input from an experienced industrial hygienist is required.
In all cases it is recommended that a trained investigator determine causes and specify ways to remediate and repair the premises. With a scope of remediation thus defined, the services of a qualified mold remediation contractor should be obtained.
Again, for the remediation of domestic or other premises where there are no attributed health effects, no mold sampling is necessary prior to remediation. HOWEVER, from a worker protection stand-point, because areas of mold growth will be disturbed causing the release into the air of spores, remediation workers must use adequate respiratory protection.
Further information is available from the Canada Mortgage and Housing Corporation at the following link:-
Disaster Remediation - Is sampling necessary?
CONTACT:-
Roger Dixon, B.Sc (Eng,) P.Eng., MPH, Industrial Hygienist, 613-476-3141
David Greer, B.A., Remediation Specialist, 613-921-1479