Guidelines for the Protection and Training
of Workers Engaged in Maintenance and Remediation
Work Associated with Mold
By: Dave Gallup
In May of
this year, the National Clearinghouse for Worker Safety and Health Training published a 35 page document
entitled Guidelines for the Protection and Training of Workers Engaged in Maintenance and Remediation
Work Associated with Mold. These guidelines were the product of two workshops in January and June of
2004 in which over 60 technical experts convened and discussed the training and protection requirements
that should be put in place to protect those who remediate mold. The stated purpose of the document is to
develop "experience-based guidelines for protecting and training mold assessors, mold remediation workers,
and workers exposed to mold in the course of maintaining building systems". It is a well written, organized
and easily understood set of guidelines. Note that the guidelines specifically do not apply to single unit,
owner-occupied residential housing units. Nor does it apply to the training necessary to effectively
perform mold assessments or remediation. It is clearly focused upon the health and protection of the
workers mentioned above. It is also clear in stating that this is intended to be a "living" document that
will need revision as our understanding of mold improves.
The guidelines begin by breaking the training audience into two groups, "maintenance" and "remediation"
which are carefully defined. Mold assessors and consultants are felt to be part of the "maintenance" group
for training purposes because it is assumed that if mold assessors meet the AIHA-LAP LLC qualifications for this
competency, they will already have had substantial training and experience with mold and safety.
The document proposes that the following four factors should be considered in determining mold exposure
Project size (square footage) of mold that is present
Type of dust control
Amount of potential release
Amount of mold work time per day
It is proposed that training should include public, office, multi-family and commercial buildings but,
again, not single family residences. It is suggested that training for those in the "maintenance" group
should be a maximum of two hours. Suggested training times for "remediation" workers is 21 hours, with some
dissention about the latter timeframe specifically cited within the guidelines. Both of these suggested
times can be modified based upon an individual's prior training and demonstrated competency.
The guidelines note that there are no OSHA standards and, consequently, they relied upon the wealth of
prior recommendations made by various groups including the ACGIH, AIHA-LAP LLC, ASTM, Health Canada, IICRC, NADCA,
NYC DOH, OSHA, and the US EPA. From these groups they pull recommended training topics for maintenance and
remediation workers engaged in general mold work and HVAC system work. They also generate a table
summarizing recommended worker protection in the same activities. Also included is a table from the US EPA
with recommended response guidelines to clean water damage to prevent mold growth.
The Guidelines may be downloaded at http://www.wetp.org/wetp/index.cfm?fuseaction=new
by clicking on the "Mold Guideline Link"
The US EPAs
guidelines for response to clean water damage may be found at http://www.epa.gov/mold/table1html
Fungus of the
By: Griselda Hernandez
Members of the genus Botrytis are ubiquitous in the environment and have been found worldwide.
They are commonly found in indoor environments and have been isolated from many substrates including
carpets, mattress dust, paper, floors, and wallboard. Although not typically considered to be soil-borne,
Botrytis has been isolated from different types of soil and sand.
Botrytis species are sensitive to humidity changes. Under high humidity conditions, water is
absorbed causing the intracellular pressure to increase and eventually rupture, thereby releasing spores
into the air. This is known as hygroscopic spore dispersal. In outdoor settings or greenhouses, large
numbers of spores are dispersed by rain or water splash. Botrytis spores are found relatively
commonly in spore trap and culture samples and are easily identified. They are recovered in the highest
numbers in the spring, where they are recovered approximately 30% of the time and least frequently in the
fall with a recovery rate of approximately 10%. When recovered, the spore density is relatively low, with
the 50th percentile value being only about 20 to 25 spores per cubic meter.
Figure 1: Botrytis frequency of detection and spore density by month.
The gray bars represent the frequency of detection, from 0 to 1 (1=100%), graphed against the left axis.
The red, green, and purple lines represent the 2.5, 50, and 97.5 percentile airborne spore densities, when
recovered, graphed against the right hand axis. (Source: EMLab™ MoldRange data. Total sample size for
this graph: 39,878.)
Botrytis spores are generally hyaline (with a tear-drop shape and a rather thick cell wall that
can be easily seen). To the untrained eye, the spores can resemble basidiospores due to a prominent scar
where they were attached to short denticles on their conidiophores (spore-producing structures) however,
Botrytis spores are much larger and more symmetrically shaped. When recovered in culture media,
the fungus has a very distinct grayish color and can be identified easily among other fungal colonies. One
distinctive characteristic of Botrytis is the production of sclerotia, which are large,
dark-colored resting structures consisting of compacted hyphae (fungal body) that can be seen with the
naked eye as dark brown to black dots. Sclerotia are wintering or "resting" structures that allow the
fungus to withstand adverse environmental conditions. These structures, under favorable conditions, may
give rise to mycelium (hyphal mass) or fruiting bodies that allow Botrytis to reestablish itself.
Fig 2: Microscopic photograph of Botrytis species
It is well documented that Botrytis is especially abundant in temperate or subtropical regions
where humidity is relatively high. However, spores and resting structures (sclerotia) have been known to
survive long periods of low humidity. Germination will be triggered once humidity increases.
Once established, Botrytis survives as a saprobe or parasite. As a saprobe, Botrytis
mainly obtains its nutrients from non-living organic matter. When living as a parasite, it is capable of
colonizing a wide range of host plants.
Botrytis is commonly known as "gray-mold" due to the color changes it undergoes as it rapidly
invades decaying plant tissue. Its growth commences as a colorless (hyaline) mass and gradually turns a
light gray to dark brown with age. Botrytis is of economic concern because it can infect a variety
of ornamental and crop plants such as cabbage, lettuce, carrots, onions, shallots, flax and legumes. Soft
fruits such as strawberries and grapes are also susceptible to Botrytis infection. In addition,
research has shown that some species may be seed-borne in some host plants which can make them vulnerable
to infection. However, not all Botrytis infection is considered to be damaging. In the wine making
industry, grapes are purposely infected with Botrytis creating "noble rot". The grapes are allowed
to over-ripen on the vine and when they eventually crack open Botrytis will colonize the fruit,
facilitating a decrease in water content and an increase in sugar concentration.
The data and other information contained in this newsletter are provided for informational purposes only
and should not be relied upon for any other purpose. Environmental Microbiology Laboratory, Inc. hereby
disclaims any liability for any and all direct, indirect, punitive, incidental, special or consequential
damages arising out of the use or interpretation of the data or other information contained in, or any
actions taken or omitted in reliance upon, this newsletter.
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