I have just had my rental house
inspected for mold, based on a tenant complaint of visible
mold(tenants have since moved out). The results are based on
non-viable methodology: Penicillium/Aspergillus levels (spores/m3)
of between 2880 to 3890 were reported in the two rooms with visible
mold on walls (outside level was 160 spores/m3). The
visible mold is an area of about 2 feet by 3 feet in one room and 6
inches by 2 feet in the other room on walls. There is no
Stachybotrys chartarum in the house according to the test. Do I
need to have someone rip out the drywall and dispose of the drywall
plastic covered? Or can I just clean with bleach? I
thought Penicillium/Aspergillus was not the toxic mold, only
Stachybotrys. So is a thorough cleaning enough? Also
legally what do I need to do to protect myself in the future for
having remediated appropriately? Should I have the same company
test spore levels after thoroughly bleach washing the walls?-P.S.
,California
The presence of visible mold to the extent described indicates that a
significant mold infestation problem exists. As a consequence,
potentially significant human exposures are likely. The
presence of visible mold even in the absence of air testing results is
sufficient in itself to undertake appropriate remediation measures.
Cleaning the walls with bleach is not an appropriate remediation
measure as it does not deal with the underlying cause of the
infestation. If you apply bleach to the interior wall surface,
only the visible mold growth will be affected. There is likely
to be a lot more mold in the wall. Though bleach will kill much
of the visible mold, the mold spores are still allergenic and thus
will cause allergenic responses in sensitive individuals on exposure.
I recommend that a professional be engaged to conduct the mold
remediation effort so as to effectively remove and replace all
infested materials and to find and resolve why the infestation
occurred in the first place. In most cases this means water
getting into the wall by intrusion or condensation. A
professional remediator is also more careful than the average home
fix-it-up person in preventing mold spores from being dispersed all
over the house where they may continue to cause exposures on
re-suspension for many months.
Test results for Penicillium/Aspergillus are relatively high
using the test and analytical methodology common to the mold
assessment industry. It is likely that a large portion of those
mold spores are from Aspergillus species, some of which like
Aspergillus versicolor are toxigenic.
Though Stachybotrys chartarum was not reported, it is likely to
be present in walls if the gypsumboard has been repeatedly wetted.
Stachybotrys produces large spores that settle out quickly.
Low airborne levels (or even absence of Stachybotrys spores)
are common in building environments where significant s
infestations exist. I suspect that Stachybotrys will be present
on the back of gypsumboard when the wall is opened.
To protect yourself legally you should conduct all mold activities by
conforming to what is good practice. Good practice in this case
is to have a professional remediator, certified by a
nationally-recognized professional group, conduct remediation
activities with clearance testing using the same testing method on
completion of all activities.
March 25, 2004
Indoor Environmental Quality (2000), Thad Godish Ph.D.,
C.I.H
Direct E-mail
00tjgodish@bsu.edu
