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Appropriate Methods
for Reducing Lead-Paint Hazards in Historic Housing
Sharon
C. Park, AIA and Douglas C. Hicks
Lead-based paint, a toxic
material, was widely used in North America on both the exteriors and interiors
of buildings until well into the second half of the twentieth century.
If a "historic" place is broadly defined in terms of time as having attained
an age of fifty years, this means that almost every historic house contains
some lead-based paint. In its deteriorated form, it produces paint chips
and lead-laden dust particles that are a known health hazard to both children
and adults. Children are particularly at risk when they ingest lead paint
dust through direct hand-to-mouth contact and from toys or pacifiers.
They are also at risk when they chew lead-painted surfaces in accessible
locations. In addition to its presence in houses, leaded paint chips,
lead dust, or lead-contaminated soil in play areas can elevate a child's
blood lead level to a degree that measures to reduce and control the hazard
should be undertaken.
The premise of this Preservation Brief is that historic housing can
be made lead-safe for children without removing significant decorative
features and finishes, or architectural trimwork that may contribute to
the building's historic character (see fig. 1). Historic housing-encompassing
private dwellings and all types of rental units-is necessarily the focus
of this Brief because federal and state laws primarily address the hazards
of lead and lead-based paint in housing and day-care centers to protect
the health of children under six years of age. Rarely are there mandated
requirements for the removal of lead-based paint from non-residential
buildings.
Ideally, most owners and managers should understand the health hazards
created by lead-based paint and voluntarily control these hazards to protect
young children. A stricter approach has been taken by some state and federal
funding programs which have compliance requirements for identifying the
problem, notifying tenants, and, in some cases, remedying lead hazards
in housing (see Legislation Sidebar, pg.xx). With new rules being written,
and new products and approaches being developed, it is often difficult
to find systematic and balanced methodologies for dealing with lead-based
paint in historic properties.
This Preservation Brief is intended to serve as an introduction to the
complex issue of historic lead-based paint and its management. It explains
how to plan and implement lead-hazard control measures to strike a balance
between preserving a historic building's significant materials and features
and protecting human health and safety, as well as the environment. It
is not meant to be a "how-to guide" for undertaking the work. Such a short-cut
approach could easily result in creating a greater health risk, if proper
precautions were not taken. Home renovators and construction workers should
be aware that serious health problems can be caused by coming into contact
with lead. For this reason, there are also laws to protect workers on
the job site (see Worker Safety Sidebar). Controlling the amount of waste
containing lead-based paint residue will also reduce the impact on the
environment. All of these considerations must be weighed against the goal
of providing housing that is safe for children. Lead in Historic Paints
Lead in Historic Paints
Lead compounds were an important component of many historic paints.
Lead, in the forms of lead carbonate and lead oxides, had excellent adhesion,
drying, and covering abilities. White lead, linseed oil, and inorganic
pigments were the basic components for paint in the 18th, 19th, and early
20th centuries. Lead-based paint was used extensively on wooden exteriors
and interior trimwork, window sash, window frames, baseboards, wainscoting,
doors, frames, and high gloss wall surfaces such as those found in kitchens
and bathrooms. Almost all painted metals were primed with red lead or
painted with lead-based paints. Even milk (casein) and water-based paints
(distemper and calcimines) could contain some lead, usually in the form
of hiding agents or pigments. Varnishes sometimes contained lead. Lead
compounds were also used as driers in paint and window glazing putty.
In 1978, the use of lead-based paint in residential housing was banned
by the federal government. Because the hazards have been known for some
time, many lead components of paint were replaced by titanium and other
less toxic elements earlier in the 20th century. Since houses are periodically
repainted, the most recent layer of paint will most likely not
contain lead, but the older layers underneath probably will. Therefore,
the only way to accurately determine the amount of lead present in older
paint is to have it analyzed.
It is important that owners of historic properties be aware that layers
of older paint can reveal a great deal about the history of a building
and that paint chronology is often used to date alterations or to document
decorative period colors (see figs. 2, 3). Highly significant decorative
finishes, such as graining, marbleizing, stenciling, polychrome decoration,
and murals should be evaluated by a painting conservator to develop the
appropriate preservation treatment that will stabilize the paint and eliminate
the need to remove it. If such finishes must be removed in the process
of controlling lead hazards, then research, paint analysis, and documentation
are advisable as a record for future research and treatment.
Planning
for Lead Hazard Reduction in Historic Housing Typical health
department guidelines call for removing as much of the surfaces that contain
lead-based paint as possible. This results in extensive loss or modification
of architectural features and finishes and is not appropriate for most
historic properties (see fig. 4). A great number of federally-assisted
housing programs are moving away from this approach as too expensive and
too dangerous to the immediate work environment. A preferred approach,
consistent with The Secretary of the Interior's Standards for the Treatment
of Historic Properties, calls for removing, controlling, or managing the
hazards rather than wholesale-or even partial-removal of the historic
features and finishes (fig. 5). This is generally achieved through careful
cleaning and treatment of deteriorating paint, friction surfaces, surfaces
accessible to young children, and lead in soil (see figs. 6, 7). Lead-based
paint that it not causing a hazard is thus permitted to remain, and, in
consequence, the amount of historic finishes, features and trimwork removed
from a property is minimized.
Because the hazard of lead poisoning is tied to the risk of ingesting
lead, careful planning can help to determine how much risk is present
and how best to allocate available financial resources. An owner, with
professional assistance, can protect a historic resource and make it lead-safe
using this three-step planning process:
- I. Identify the historical significance of the building and architectural
character of its features and finishes;
- II. Undertake a risk assessment of interior and exterior surfaces
to determine the hazards from lead and lead-based paint; and,
- III. Evaluate the options for lead hazard control in the context
of historic preservation standards.
I. Identify the historical significance of
the building and architectural character of its features and finishes
The historical significance, integrity, and architectural character
of the building always need to be assessed before work is undertaken that
might adversely affect them. An owner may need to enlist the help of a
preservation architect, building conservator or historian. The State Historic
Preservation Office (SHPO) may be able to provide a list of knowledgeable
preservation professionals who could assist with this evaluation.
Features and finishes of a historic building that exhibit distinctive
characteristics of an architectural style; represent work by specialized
craftsmen; or possess high artistic value should be identified so they
can be protected and preserved during treatment. When it is absolutely
necessary to remove a significant architectural feature or finish-as noted
in the first two priorities listed below-it should be replaced with a
new feature and finish that matches in design, detail, color, texture,
and, in most cases, material.
Finally, features and finishes that characterize simple, vernacular
buildings should be retained and preserved; in the process of removing
hazards, there are usually reasonable options for their protection. Wholesale
removal of historic trim, and other seemingly less important historic
material, undermines a building's overall character and integrity and,
thus, is never recommended.
For each historic property, features will vary in significance. As part
of a survey of each historic property (see figure 8), a list of priorities
should be made, in this order:
- Highly significant features and finishes that should always be protected
and preserved;
- Significant features and finishes that should be carefully repaired
or, if necessary, replaced in-kind or to match all visual qualities;
and
- Non-significant or altered areas where removal, rigid enclosure,
or replacement could occur.
This hierarchy gives an owner a working guide for making decisions about
appropriate methods of removing lead paint.
II. Undertake a risk assessment of interior
and exterior surfaces to determine hazards from lead and lead-based paint.
While it can be assumed that most historic housing contains
lead-based paint, it cannot be assumed that it is causing a health risk
and should be removed. The purpose of a risk assessment is to determine,
through testing and evaluation, where hazards from lead warrant remedial
action (see fig. 9). Testing by a specialist can be done on paint, soil,
or lead dust either on-site or in a laboratory using methods such as x-ray
fluorescence (XRF) analyzers, chemicals, dust wipe tests, and atomic absorption
spectroscopy. Risk assessments can be fairly low cost investigations of
the location, condition, and severity of lead hazards found in house dust,
soil, water, and deteriorating paint. Risk assessments will also address
other sources of lead from hobbies, crockery, water, and the parents'
work environment. A public health office should be able to provide names
of certified risk assessors, paint inspectors, and testing laboratories.
These services are critical when owners are seeking to implement measures
to reduce suspected lead hazards in housing, day-care centers, or when
extensive rehabilitations are planned.
The risk assessment should record:
- the paint's location
- the paint's condition
- lead content of paint and soil
- the type of surface
- (friction; accessible to children for chewing; impact)
- how much lead dust is actively present
- how the family uses and cares for the house
- the age of the occupants who might come into contact with lead paint.
It is important from a health standpoint that future tenants, painters,
and construction workers know that lead-based paint is present, even under
treated surfaces, in order to take precautions when work is undertaken
in areas that will generate lead dust. Whenever mitigation work is completed,
it is important to have a clearance test using the dust wipe method
to ensure that lead-laden dust generated during the work does not remain
at levels above those established by the Environmental Protection Agency
(EPA) and the Department of Housing and Urban Development (HUD) (see Action
Levels Chart). A building file should be maintained and updated whenever
any additional lead hazard control work is completed.
Hazards should be removed, mitigated, or managed in the order of their
health threat, as identified in a risk assessment (with 1. the greatest
risk and 8. the least dangerous):
- 1. Peeling, chipping, flaking, and chewed interior lead-based paint
and surfaces
- 2. Lead dust on interior surfaces
- 3. High lead in soil levels around the house and in play areas (check
state requirements)
- 4. Deteriorated exterior painted surfaces and features
- 5. Friction surfaces subject to abrasion (windows, doors, painted
floors)
- 6. Accessible, chewable surfaces (sills, rails) if small children
are present
- 7. Impact surfaces (baseboards and door jambs)
- 8. Other interior surfaces showing age or deterioration (walls and
ceilings)
III. Evaluate options for hazard control in
the context of historic preservation standards. The Secretary
of the Interior's Standards for the Treatment of Historic Properties-established
principles used to evaluate work that may impact the integrity and significance
of National Register properties-can help guide suitable health control
methods. The preservation
standards call for the protection of historic materials and historic character
of buildings through stabilization, conservation, maintenance, and repair.
The rehabilitation standards
call for the repair of historic materials with replacement of a character-defining
feature appropriate only when its deterioration or damage is so extensive
that repair is infeasible. From a preservation standpoint, selecting a
hazard control method that removes only the deteriorating paint,
or that involves some degree of repair, is always preferable to the total
replacement of a historic feature.
By tying the remedial work to the areas of risk, it is possible to limit
the amount of intrusive work on delicate or aging features of a building
without jeopardizing the health and safety of the occupants. To make historic
housing lead-safe, the gentlest method possible should be used to remove
the offending substance-lead-laden dust, visible paint chips, lead in
soil, or extensively deteriorated paint. Overly aggressive abatement may
damage or destroy much more historic material than is necessary to remove
lead paint, such as abrading historic surfaces. Another reason for targeting
paint removal is to limit the amount of lead dust on the work site. This,
in turn, helps avoid expensive worker protection, cleanup, and disposal
of larger amounts of hazardous waste.
Whenever extensive amounts of lead must be removed from a property,
or when methods of removing toxic substances will impact the environment,
it is extremely important that the owner be aware of the issues surrounding
worker safety, environmental controls, and proper disposal (see fig. 10,
11). Appropriate architectural, engineering and environmental professionals
should be consulted when lead hazard projects are complex.
Following are brief explanations of the two approaches for controlling
lead hazards, once they have been identified as a risk. These controls
are recommended by the Department of Housing and Urban Development in
Guidelines for the Evaluation and Control of Lead-Paint Hazards in
Housing, and are summarized here to focus on the special considerations
for historic housing:
Interim Controls: Short-term solutions include thorough
dust removal; thorough washdown and clean-up of exposed surfaces; paint
film stabilization and repainting; covering of lead-contaminated soil;
and making tenants aware of lead hazards. Interim controls require ongoing
maintenance and evaluation.
Hazard Abatement: Long-term solutions are defined as having
an expected life of 20 years or more, and involve permanent removal of
hazardous paint through chemicals, heat guns or controlled sanding/abrasive
methods; permanent removal of deteriorated painted features through replacement;
the removal or permanent covering of contaminated soil; and the use of
enclosures (such as drywall) to isolate painted surfaces. The use of specialized
elastomeric encapsulant paints and coatings can be considered as permanent
containment of lead-based paint if they receive a 20-year manufacturer's
warranty or are approved by a certified risk assessor. One should be aware
of their advantages and drawbacks for use in historic housing.
Within the context of the historic preservation standards, the most
appropriate method will always be the least invasive. More invasive approaches
are considered only under the special circumstances outlined in the three-step
process. An inverted triangle (see fig. 12) shows the greatest number
of residential projects fall well within the "interim controls" section.
Most housing can be made safe for children using these sensitive treatments,
particularly if no renovation work is anticipated. Next, where owners
may have less control over the care and upkeep of housing and rental units,
more aggressive means of removing hazards may be needed. Finally, large-scale
projects to rehabilitate housing or convert non-residential buildings
to housing may successfully incorporate "hazard abatement" as a part of
the overall work.
Appropriate
Methods for Controlling Lead Hazards In selecting appropriate
methods for controlling lead hazards, it is important to refer to Step
I. of the survey where architecturally significant features and finishes
are identified and need to be preserved. Work activities will vary according
to hazard abatement needs; for example, while an interim control would
be used to stabilize paint on most trimwork, an accessible window sill
might need to be stripped prior to repainting. Since paint on a window
sill is usually not a significant finish, such work would be appropriate.
Other appropriate methods for controlling lead hazards are summarized
in the accompanying chart (see fig. 13).
The method selected for removing or controlling the hazards has a direct
bearing on the type of worker protection as well as the type of disposal
needed, if waste is determined to be hazardous (see fig. 14). Following
are examples of appropriate methods to use to control lead hazards within
an historic preservation context.
Historic Interiors (deteriorating paint and chewed surfaces).
Whenever lead-based paint (or lead-free paint covering older painted surfaces)
begins to peel, chip, craze, or otherwise comes loose, it should be removed
to a sound substrate and the surface repainted. If children are present
and there is evidence of painted surfaces that have been chewed, such
as a window sill, then these surfaces should be stripped to bare wood
and repainted. The removal of peeling, flaking, chalking, and deteriorating
paint may be of a small scale and undertaken by the owner, or may be extensive
enough to require a paint contractor. In either case, care must be taken
to avoid spreading lead dust throughout the dwelling unit. If the paint
failure is extensive and the dwelling unit requires more permanent hazard
removal, then an abatement contractor should be considered. Many states
are now requiring that this work be undertaken by specially trained and
certified workers.
If an owner undertakes interim controls, it would be advisable to receive
specialized training in handling lead-based paint. Such training emphasizes
isolating the area, putting plastic sheeting down to catch debris, turning
off mechanical systems, taping registers closed, and taking precautions
to clean up prior to handling food. Work clothes should be washed separately
from regular family laundry. The preferred method for removing flaking
paint is
the wet sanding of surfaces because it is gentle to the substrate and
controls lead dust. The key to reducing lead hazards while stabilizing
flaking paint is to keep the surfaces slightly damp to avoid ingesting
lead dust. Wet sanding uses special flexible sanding blocks or papers
that can be rinsed in water or used along with a bottle mister. This method
will generally not create enough debris to constitute hazardous waste
(see fig. 15).
Other methods for selectively removing more deteriorated paint in historic
housing include controlled sanding, using low-temperature heat guns, or
chemical strippers. Standard safety precautions and appropriate worker
protection should be used. Methods to avoid include uncontrolled
dry abrasive methods, high heat removal (lead vaporizes at 1100o F), uncontrolled
water blasting, and some chemicals considered carcinogenic (methylene
chloride). When possible and practicable, painted elements, such as radiators,
doors, shutters, or other easily removable items, can be taken to an off
site location for paint removal.
In most cases, when interior surfaces are repainted, good quality interior
latex or oil/alkyd paints may be used. The paint and primer system must
be compatible with the substrate, as well as any remaining, well-bonded,
paint.
Encapsulant paints and coatings, developed to contain lead-based paint,
rely on an adhesive bonding of the new paint through the layers of the
existing paint. The advantages of these special paint coatings is that
they allow the historic substrate to remain in-place; reduce the amount
of existing paint removed; can generally be applied without extensive
worker protection; and are a durable finish. (They cannot, however, be
used on friction surfaces.) The drawbacks include their ability to obscure
carved details, unless thinly applied in several applications, and difficulty
in future removal. If a specialized paint, such as an elastomeric encapsulant
paint, is considered, the manufacturer should be contacted for specific
instructions for its application. Unless these specialized paint systems
are warranted for 20 years, they are considered as less permanent interim
controls.
Lead-dust on interior finishes. Maintaining and washing
painted surfaces is one of the most effective measures to prevent lead
poisoning. Houses kept in a clean condition, with paint film intact and
topcoated with lead-free paint or varnish, may not even pose a health
risk. Dust wipe tests, which are sent to a laboratory for processing,
can identify the level of lead dust present on floors, window sills, and
window troughs. If lead dust is above acceptable levels, then specially
modified maintenance procedures can be undertaken to reduce it. All paints
deteriorate over time, so maintenance must be ongoing to control fine
lead dust. The periodic washing of surfaces with a surfactant, such as
tri-sodium phosphate (TSP) or its equivalent, loosens dirt and removes
lead dust prior to a water rinse and touch-up painting, if necessary.
This interim treatment can be extremely beneficial in controlling lead
dust that is posing a hazard (see fig. 16).
Soil/landscape. Soil around building foundations may contain
a high level of lead from years of chalking and peeling exterior paint.
This dirt can be brought indoors on shoes or by pets and small children
if they play outside a house. Lead in the soil is generally found in a
narrow band directly adjacent to the foundation. If the bare soil tests
high in lead (see Action Levels Chart), it should be replaced to a depth
of several inches or covered with new sod or plantings. Care should be
taken to protect historic plantings on the building site and, in particular,
historic landscapes, while mitigation work is underway (see fig. 17).
If an area has become contaminated due to a variety of environmental conditions
(for example, a smelter nearby or water tanks that have been sandblasted
in the past), then an environmental specialist as well as a landscape
preservation architect should be consulted on appropriate site protection
and remedial treatments. It is inappropriate to place hard surfaces, such
as concrete or macadam, over historically designed landscaped areas, which
is often the recommendation of typical abatement guidelines.
Deteriorating paint on exteriors. Deteriorating exterior
paint will settle onto window ledges and be blown into the dwelling, and
will also contaminate soil at the foundation, as previously discussed.
Painted exteriors may include wall surfaces, porches, roof trim and brackets,
cornices, dormers, and window surrounds. Most exteriors need repainting
every 5-10 years due to the cumulative effect of sun, wind, and rain or
lack of maintenance. Methods of paint removal that do not abrade or damage
the exterior materials should be evaluated. Because there is often more
than one material (for example, painted brick and galvanized roof ornaments),
the types of paint removal or paint stabilization systems need to be compatible
with each material (see fig. 18). If paint has failed down to the substrate,
it should be removed using either controlled sanding/scraping, controlled
light abrasives for cast iron and durable metals, chemicals, or low heat.
If chemicals are used, it may be necessary to have the contractor contain,
filter, or otherwise treat any residue or rinse water. Environmental regulations
must be checked prior to work, particularly if a large amount of lead
waste will be generated or public water systems affected.
A cost analysis may show that, in the long run, repair and maintenance
of historic materials or in-kind replacement can be cost effective. Due
to the physical condition and location of wood siding, together with the
cost of paint removal, a decision may be made to remove and replace these
materials on some historic frame buildings. If the repair or replacement
of historic cladding on a primary elevation is being undertaken, such
replacement materials should match the historic cladding in material,
size, configuration, and detail (see fig. 19). The use of an artificial
siding or aluminum coil stock panning systems over wooden trimwork or
sills and lintels (as recommended in some abatement guidelines) is not
appropriate, particularly on principal facades of historic buildings because
they change the profile appearance of the exterior trimwork and may damage
historic materials and detailing during installation. Unless the siding
is too deteriorated to warrant repair and the cost is too prohibitive
to use matching replacement materials (i.e., wood for wood), substitute
materials are not recommended.
The use of specialized encapsulant paint coatings on exteriors-in particular,
moist or humid climates, and, to some extent, cold climates-is discouraged
because such coatings may serve to impede the movement of moisture that
naturally migrates through other paints or mask leaks that may be causing
substrate decay. Thus, a carefully applied exterior paint system (either
oil/alkyd or latex) with periodic repainting can be very effective.
Friction Surfaces. Interior features with surfaces that-functionally-rub
together such as windows and doors, or are subject to human wear and tear,
such as floor and steps, are known as friction surfaces. It is unclear
how much lead dust is created when friction surfaces that contain lead-based
paint, but are top-coated with lead-free paint, rub together because much
of the earlier paint may have worn away. For example, if lead dust levels
around windows or on painted floors are consistently above acceptable
levels, treating nearby friction surfaces should be considered. If surfaces,
such as operable windows, operable doors, painted porch decks, painted
floors and painted steps appear to be generating lead dust, they should
be controlled through isolating or removing the lead-based paint. Window
and door edges can be stripped or planed, or the units stripped on or
off site to remove paint prior to repainting. Simple wooden stops and
parting beads for windows, which often split upon removal, can be replaced.
If window sash are severely deteriorated, it is possible to replace them;
and vinyl jamb liners can effectively isolate remaining painted window
jambs (see fig. 20). When windows are being treated within rehabilitation
projects, their repair and upgrading are always recommended. In the event
that part or all of a window needs to be replaced, the new work should
match in size, configuration, detail, and, whenever possible, material.
Painted floors often present a difficult problem because walking on
them abrades the surface, releasing small particles of lead-based paint.
It is difficult to remove lead dust between the cracks in previously painted
strip flooring even after sanding and vacuuming using special High Efficiency
Particulate Air (HEPA) filters to control the lead dust. If painted floors
are not highly significant in material, design, or craftsmanship, and
they cannot be adequately cleaned and refinished, then replacing or covering
them with new flooring may be considered. Stair treads can be easily fitted
with rubber or vinyl covers (see fig. 21).
Accessible, projecting, mouthable surfaces. Accessible,
chewable surfaces that can be mouthed by small children need not be removed
entirely, as some health guidelines recommend. These accessible surfaces
are listed as projecting surfaces within a child's reach, including window
sills, banister railings, chair rails, and door edges. In many cases,
the projecting edges can have all paint removed using wet sanding, a heat
gun or chemical strippers, prior to repainting the feature (see fig. 22).
If the homeowner feels that there is no evidence of unsupervised mouthing
of surfaces, a regular paint may be adequate once painted surfaces have
been stabilized. An encapsulant paint that adhesively bonds existing paint
layers onto the substrate extends durability. While encapsulant paint
systems are difficult to remove from a surface in the future, they permit
retention of the historic feature itself. If encapsulant paint is used
on molded or decorative woodwork, it should be applied in several thin
coats to prevent the architectural detail from being obscured by the heavy
paint (see fig 23).
Impact Surfaces. Painted surfaces near doorways and along
corridors tend to become chipped and scraped simply because of their location.
This is particularly true of baseboards, which were designed to protect
wall surfaces, and also for doorjambs. Owners should avoid hitting painted
impact surfaces with vacuums, brooms, baby carriages, or wheeled toys.
Adding new shoe moldings can give greater protection to some baseboards.
In most cases, stabilizing loose paint and repainting with a high quality
interior paint will provide a durable surface. Clear panels or shields
can be installed at narrow doorways, if abrasion continues, or these areas
can be stripped of paint and repainted. Features in poor condition may
need to be replaced with new, matching materials (see fig. 24).
Other surfaces showing age or deterioration/ walls and ceilings.
Many flat wall surfaces and ceilings were not painted with lead-based
paint, so will need to be tested for its presence prior to any treatment.
Flat surfaces that contain deteriorating lead-based paint should be repaired
following the responsible approach previously cited (i.e., removing loose
paint to a sound substrate, then repairing damaged plaster using a skim
coat or wet plaster repair (see fig. 25). Drywall is used only
when deterioration is too great to warrant plaster repair. If walls and
ceilings have a high lead content, and extensive paint removal is not
feasible, there are systems available that use elastomeric paints with
special fabric liners to stabilize older, though intact, wall surfaces.
If a new drywall surface needs to be applied, care should be taken that
the historic relationship of wall to trim is not lost. Also, if there
are significant features, such as crown moldings or ceiling medallions,
they should always be retained and repaired (see fig. 26).
Maintenance
after Hazard Control Treatment Following treatment, particularly
where interim controls have been used, ongoing maintenance and re-evaluation
become critical. In urban areas, even fully lead-safe houses can be re-contaminated
within a year from lead or dirt outside the immediate property. Thus,
housing interiors must be kept clean, once lead hazard control measures
have been implemented. Dust levels should be kept down by wet sweeping
porch steps and entrances on a regular basis. Vacuum cleaning and dusting
should be repeated inside on a weekly basis or even more often. Vinyl,
tile, and wood floor surfaces should be similarly damp mopped. Damp washing
of window troughs and sills to remove new dust should be encouraged several
times a year, particularly in the spring and fall when windows will be
open. Carpets and area rugs should be steam cleaned or washed periodically
if they appear to hold outside dirt.
Housing should be inspected frequently for signs of deterioration by
both owner and occupant. Tenants need to be made aware of the location
of lead-based paint under lead-free top coats and instructed to contact
the owners or property managers when the paint film becomes disturbed
(see figure 27). Any leaks, peeling paint, or evidence of conditions that
may generate lead-dust should be identified and corrected immediately.
Occupants must be notified prior to any major dust-producing project.
Dry sanding, burning, compressed air
cleaning or blasting should be not be used. Repairs, repainting, or
remodeling activities that have the potential of raising significant amounts
of lead dust should be undertaken in ways that isolate the area, reduce
lead-laden dust as much as possible, and protect the occupants.
Yearly dust wipe tests are recommended to ensure that dust levels remain
below actionable levels. Houses or dwelling units that fail the dust-wipe
test should be thoroughly re-cleaned with TSP, or its equivalent, washed
down, wet vacuumed and followed by HEPA vacuuming, if necessary, until
a clearance dust wipe test shows the area to be under actionable levels
(see Action Levels chart). Spaces that are thoroughly cleaned and maintained
in good condition are not a health risk (see fig. 28).
Conclusion The three-step planning
process outlined in this Brief provides owners and managers of historic
housing with responsible methods for protecting historic paint layers
and architectural elements, such as windows, trimwork, and decorative
finishes. Exposed decorative finishes, such as painted murals or grained
doors can be stabilized by a paint conservator with a glazed or varnished
layer without destroying their significance.
Reducing and controlling lead hazards can be successfully accomplished
without destroying the character-defining features and finishes of historic
buildings. Federal and state laws generally support the reasonable control
of lead-based paint hazards through a variety of treatments, ranging from
modified maintenance to selective substrate removal. The key to protecting
children, workers, and the environment is to be informed about the hazards
of lead, to control exposure to lead dust and lead in soil, and to follow
existing regulations. In all cases, methods that control lead hazards
should be selected that minimize the impact to historic resources while
ensuring that housing is lead-safe for children.
ACTION LEVELS Readers should become
familiar with terminology and basic levels that trigger concern and/or
action. Check with the appropriate authorities if you have questions and
to verify applicable action levels which may
change over time.
Blood lead levels: Generally from drawn blood and not a finger
stick test which can be unreliable. Units are measured in micrograms per
deciliter (ug/dl) and reflect the 1995 standards from the Centers
of Disease Control:
Children: 10 ug/dl; level of concern; find source of lead
15 ug/dl and above; intervention, counseling, medical monitoring.
20 ug/dl and above; medical treatment
Adults: 25 ug/dl; level of concern; find source of lead
50 ug/dl ; OSHA standard for medical removal from the worksite
Lead in paint: Differing methods report results in differing
units. Lead is considered a potential hazard if above the following
levels, but can be a hazard at lower levels, if improperly handled.
These are the current numbers as identified by the Department of Housing
and Urban Development (1995):
Lab analysis of samples:
5,000 milligram per kilogram (mg/kg) or 5,000 parts per million (ppm),
or
0.5% lead by weight.
XRF reading: in milligram per centimeter squared
1 mg/cm2
lead dust wipe test: in micrograms per square foot
Floors 100 ug/ft2;
Window sills 500 ug/ft2;
Window troughs 800 ug/ft2
Lead in soil: high contact bare play areas, listed as parts per
million (ppm):
concern: 400 ppm
interim control 2,000 ppm
hazard abatement 5,000 ppm
LEAD-BASED PAINT LEGISLATION
The following summarizes several important regulations that
affect lead-hazard reduction projects. Owner's should be aware that regulations
change and they have a responsibility to check state and local ordinances
as well.
Federal Legislation Title X
(Ten) Residential Lead-Based Paint Hazard Reduction Act of 1992 is
part of the Housing and Community Development Act of 1992 (Public Law
102-550). It established that HUD issue "The Guidelines for the Evaluation
and Control of Lead-Based Paint Hazards in Housing" (1995) to outline
risk assessments, interim controls, and abatement of lead-based paint
hazards in housing. Title X calls for the reduction of lead in
housing that is federally supported and outlines the federal responsibility
towards its own residential units and the need for disclosure of lead
in residences, even private residences, prior to sale.
Interim Final Regulations of Lead in Construction Standards (29CFR
1926.62). Issued by the Department of Labor, Occupational Safety and
Health Administration (OSHA), these regulations address worker safety,
training, and protective measures. It is based in part on environmental
air sampling to determine the amount of lead dust generated by various
activities.
Toxic Substance Control Act; Title IV. The Environment Protective
Agency (EPA) has jurisdiction for setting standards for lead abatement.
Also, EPA controls the handling and disposal of hazardous waste generated
during an abatement project. EPA will develop standards to establish lead
hazards, to certify abatement contractors, and to establish work practice
standards for abatement activity. EPA Regional Offices can provide guidance
on the appropriate regulatory agency for states within their region.
State Laws: States generally have the authority to regulate the
removal and transportation of lead based paint and the generated waste
generally through the appropriate state environmental and public health
agencies. Most requirements are for mitigation in the case of a lead-poisoned
child, or for protection of children, or for oversight to ensure the safe
handling and disposal of lead waste. When undertaking a lead-based paint
reduction program, it is important to determine which laws are in place
that may affect your project. Call the appropriate officials.
Local Ordinances: Check with local health departments, Poison
Control Centers, and offices of housing and community development to determine
if there are laws that require compliance by building owners. Rarely are
owners required to remove lead-based paint and most laws are to ensure
safety if a project is undertaken as part of a larger rehabilitation.
Special use permits may be required when an environmental impact may occur
due to a cleaning treatment that could contaminate water or affect water
treatment. Determine whether projects are considered abatements and will
require special contractors and permits.
Owner's Responsibility: Owners are ultimately responsible for
ensuring that hazardous waste is properly disposed of when it is generated
on their own sites. Owners should check with their state office to determine
if the abatement project requires a certified contractor. ( National certification
requirements are not yet in place.) Owners should establish that the contractor
is responsible for the safety of the crew and that all applicable laws
are followed, and that transporters and disposers of hazardous waste have
liability insurance as a protection for the owner. If an interim treatment
is being used to reduce lead hazards, the owner should notify the contractor
that lead-based paint is present and that it is the contractor's responsibility
to follow appropriate work practices to protect workers and to complete
a thorough clean-up to ensure that lead-laden dust is not present after
the work is completed.
Worker Safety Current worker
safety standards were established by OSHA's 29 CFR Part 1926, Lead Exposure
in Construction; Interim Final Rule, which became effective June 3, 1993.
These standards base levels of worker protection on exposure to airborne
lead dust. They are primarily targeted to persons working within the construction
industry, but apply to any workers who are exposed to lead dust for longer
than a specific amount of time and duration. The Interim Final Rule establishes
an action level of 30 micrograms of lead dust per cubic meter of air (30
ug/m3) based on an eight hour, time-weighted average, as the level
at which employers must initiate compliance activities; and it also establishes
50 ug/m3 of lead dust as the permitted exposure level (PEL) for
workers.
The standard identifies responsibilities before, during, and after the
actual abatement activity necessary to protect the worker. Before the
project begins, it requires an exposure assessment, a written compliance
plan, initial medical surveillance, and training. The exposure assessment
determines whether a worker may be exposed to lead. OSHA has identified
a number of work tasks expected to produce dust levels between 50 and
500 ug/m3 of air, including manual demolition, manual scraping,
manual sanding, heat gun applications, general cleanup, and power tool
use when the power tool is equipped with a dust collection system. It
is an OSHA requirement that, at a minimum, a HEPA filtered half-face respirator
with a protection factor of 10 be used for these operations. Initial blood
lead level (BLL) base lines are established for each worker. Actual dust
levels are monitored by air sampling of representative work activities,
generally by an industrial hygienist or an environmental monitoring firm.
Protective equipment is determined by the dust level. For all workers
exposed at, or above, the action level for over 30 days in a 12-month
period, BLLs are tested on a regular basis of every 2 months for the first
6 months and every 6 months thereafter. After completing a project, maintenance,
medical surveillance, and recordkeeping responsibilities continue.
HEPA vacuums, HEPA respirators, and HEPA filters, which substantially
reduce exposure to lead dust, are available through laboratory safety
and supply catalogs and vendors.
Copies of 29 CFR Part 1926, Lead Exposure in Construction: Interim Final
Rule, are available from the Department of Labor, Occupational Safety
and Health Administration, or may be found in any library with a current
edition of the Code of Federal Regulation (CFR).
Further Reading Chase, Sara
B. Preservation Brief 28: Painting Historic Interiors. Washington,
DC: US Department of the Interior, National Park Service, 1992.
"Coping with Contamination: A Primer for Preservationist," Information;
Booklet No. 70. Washington, DC: National Trust for Historic Preservation,
1993.
Historic Buildings and the Lead Paint Hazard. Hartford,
CT: Connecticut Historical Commission, 1990.
"Health Hazards in National Park Service Buildings", NPS-76 Housing
Design and Rehabilitation. Washington DC: US Department of the
Interior, National Park Service, 1995.
Guidelines for the Evaluation and Control of Lead-Based Paint Hazards
in Housing. Washington, DC: US Department of Housing and Urban Development,
1995.
Jandl, H. Ward. Preservation Brief 18: Rehabilitating Historic Interiors
- Identifying and Preserving Character-defining Elements. Washington,
DC: US Department of the Interior, National Park Service, 1988.
MacDonald, Marylee." Getting Rid of Lead." Old House Journal,
July/Aug 1992.
Myers, John H. Preservation Briefs 9; Repair of Historic Wooden
Windows. Washington, DC: US Department of the Interior, National
Park Service, 1981.
OSHA Lead in Construction Standard (29 CFR 1926.62), Occupational Safety
and Health Administration, May 4, 1993 (Federal Register).
Park, Sharon C. and Camille Martone. "Lead-Based Paint in Historic Buildings,"
CRM Bulletin. Washington, DC: US Deparartment of the Interior,
National Park Service. Vol. 13, No. 1, 1990.
Park, Sharon C. "Managing Lead in Building Interiors: An Emerging Approach,"
Interiors Handbook for Historic Buildings, Vol. II. Washington
DC: Historic Preservation Education Foundation, 1993.
Park, Sharon C ."What to do about Lead-Based Paint," CRM Bulletin.
Washington, DC: U.S. Department of the Interior, National Park Service.
Vol. 17, No. 4, 1994.
The Secretary of the Interior's Standards for the Treatment of Historic
Properties. Washington, DC: US Department of the Interior, National Park
Service, 1992.
Title X (Residential Lead-Based Paint Hazard Reduction Act of 1992)
of Housing and Community Development Act of 1992 (P.L. 102-550), October
28, 1992.
Weeks, Kay D. and David Look, AIA. Preservation Briefs 10; Exterior
Paint Problems on Historic Woodwork. Washington DC: US Department
of the Interior, National Park Service. 1982.
Glossary of Terms Deteriorated
Lead-Based Paint: Paint known to contain lead that shows signs of
peeling, chipping, chalking, blistering, alligatoring or otherwise separating
from its substrate.
Dust Removal: The process of removing dust to avoid creating
a greater problem of spreading lead particles; usually through wet or
damp collection or through the use of special HEPA vacuums.
Hazard Abatement: Long-term measures to remove the hazards of
lead-based paint through selective paint stripping of deteriorated areas;
or, in some cases, replacement of deteriorated features.
Hazard Control: Measures to reduce lead hazards to make housing
safe for young children. Can be accomplished with interim (short-term)
or hazard abatement (long-term) controls.
Interim Control: Short-term methods to remove lead dust, stabilize
deteriorating surfaces, and repaint surfaces. Maintenance can ensure that
housing remains lead-safe.
Lead-based Paint: Any existing paint, varnish, shellac or other
coating that is in excess of 1.0 mg/cm2 as measured by an XRF detector
or greater than 0.5% by weight from laboratory analysis ( 5,000 ppm, 5,000
ug/g, or 5,000 mg/kg). For new products, the Consumer Safety Act
notes 0.06% as the maximum amount of lead allowed in paint.
Lead-safe: The act of making a property safe from contamination
by lead-based paint, lead-dust, and lead in soil generally through short
and long-term methods to remove it, or to isolate it from small children.
Risk Assessment: An on-site investigation to determine the presence
and condition of lead-based paint, including limited test samples, and
an evaluation of the age, condition, housekeeping practices, and uses
of a residence.
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