Soot

==What is Soot?==
Smoke is a complex mixture of different gases and particles, which results from
the various materials that burn during a fire event. A typical structure fire (residential home or business) may involve the destruction of plastics, foams, fabrics,
carpets, wood products, synthetic fabrics, wool, and asbestos-containing materials.
Smoke is the result of incomplete combustion, which produces tiny particles of carbon
in the air. When deposited, these particulates are identified as soot. 
Soot will usually adhere to a wall or any other surface that is cooler than the heart
of the fire. In fire investigations, a wall free from soot may be an indicator of where
the fire began because the fire would burn at a higher temperature in this area. As
a fire dies down, the smoke it has caused will disperse leaving behind a residue of
quickly cooling particles which is generally referred to as soot.
All materials involved in a fire cause odors. Typically, soot is
representative of what has burned, but may include byproducts
that at first seem unrelated to the original material. For example,
hydrogen cyanide is a byproduct of burning wool. When wood
burns it can produce manganese and benzene. As many products
as there are in the world, there are an equal number of byproducts
produced in a fire. Each fire is different based on the contents of
what has burned during the event.
Organic and inorganic materials produce different types of
smoke residue or soot. These residues may be present on surfaces
that conservators may be tasked with treating. Burnt organic material produces soot that is hard to see and often has a very pungent
odor. This is known as protein smoke. It can discolor paints and
varnishes. Protein smoke can disperse over large areas and attach
itself to everything.
How the fire burns and how much moisture is in the air while
the fire burns, plays a role in soot deposition on articles. The
amount of moisture in the air is a key component in whether the
smoke that is produced is wet or dry.
There are several types of smoke or soot, which may be present
on a surface that conservators might be tasked with treating:
* Wet Smoke—can present as a sticky residue or soot, and is often associated with a smoldering type of fire and often will have a strong odor.
* Dry Smoke—associated with a fast-burning fire and occurs at high temperatures.
*Protein—often present in soot, usually invisible, it can discolor paints and varnishes and often has a very pungent odor. Protein odors could be caused by food on the stove burning slowly or other sources. The slow burn allows the protein to disperse and attach itself to everything, producing a strong odor.
==Treatment==
See BPG Surface Cleaning
See PMG Surface Cleaning
===Case Study: Some Observations: Removing Soot Residue from Contemporary Paintings (by Rustin Levenson)===
(This article originally appeared in The Hidden Hazards of Fire Soot(AIC News September 2010 (35:5) 1, 3-5))
Soot removal treatments on the 108 paintings that were in
the fire at the Harold Golen Gallery met with varying results.
Ultimately, 85 of the painting were successfully cleaned.
The treatments and research were presented in a paper with
my associates Veronica Romero and Kelly O’Neill at the
Paintings Specialty Group session at the 2010 AIC meeting
in Milwaukee.
We found that working with Groomstik or with vulcanized rubber sponges on the face of the paintings was unsatisfactory. Any pressure on the paint surface drove the soot into
the paint layer, with little hope of removal. The exceptions
to this were the handful of varnished paintings where dry
methods successfully removed some soot without affecting
the paint layer. Additionally, we observed that the presence
of accretions from the collapsed ceiling on the face of the
paintings could have caused scratching if the sponges were
rubbed across the paint surface.
Traditional wet cleaning mixtures for soot removal,
dibasic ammonium citrate in water and naphtha emulsions,
were the first solutions tested. Combinations of these solutions were successful on 24 oil paintings. Other solvents were also tested. For one acrylic painting,
soot was released by a solution of mineral spirits and trimethlypentane followed by an application of VM&P Naphtha. A xylene emulsion was successful with another work.
Ultimately, there were a number of paintings that did not
respond to traditional conservation treatments. Although the
insurance company would have discarded these paintings,
they offered a unique opportunity for research. Solvents and
commercial products were tested. Further success was realized with stronger chelating agents such as EDTA(ethene,
diamine, tetra acidic acid) and Versenol. Soot was removed
from some works with the addition of detergents such as
Vulpex to the conservation solutions. The soot solvent,
ethylene glycol monobutyl ether, was found to be a useful
component in cleaning some of the acrylic paintings.
In summary, if a conservator is confronted with soot
damaged paintings we can offer the following advice.
*Wear appropriate personal protective equipment (PPE). Consult with an industrial hygienist or health professional about what type of filtration is needed for respirator use.
*Vacuum the reverse and clean it with a vulcanized rubber sponge.
*Vacuum, without pressure, near the paint surface. Forego the vulcanized rubber sponge on the paint surface except in cases of very light soot or heavily varnished paintings. 
*Try traditional solutions of chelating agents such as ammonium citrate in distilled water and naphtha emulsions.
*Other solutions to test could include other petroleum distillates, alone or in emulsions, xylene emulsions, ethanol, or mixtures of Versenol, VM&P Naphtha, and distilled water.
*Detergent mixtures such as Vulpex in distilled water or VM&P Naphtha could also be tested.
*The use of carbon solvents/degreasers such as ethylene glycol monobutyl ether, diluted, alone, or combined with detergents such as Vulpex could also increase success in removing these residues.
*Careful rinsing of all solutions is also recommended, blotting or using a PVOH sponge for the final rinse so that no residue is left on the surface.
This information is shared in the hopes that other
conservators and conservation scientists will undertake
further testing and research into these materials.
==Health & Safety==
Some of the information included on this wiki may be out of date, particularly with regard to toxicological data and regulatory standards. Also, because new information on safety issues is continually published, resources outside of AIC should be consulted for more specific information. 
(This article originally appeared as The Hidden Hazards of Fire Soot(AIC News September 2010 (35:5) 1, 3-5). It may have been updated).
The documented hazards of fire soot date back to 1775 when Percivall Pott, an
English surgeon, discovered an association between exposure to soot and a high
incidence of scrotal cancer in chimney sweeps. This was the first occupational link
to cancer, which ultimately led to the science of epidemiology and the Chimney
Sweeper’s Act of 1788.
Exposure to soot may not be an obvious health hazard to conservators who are
exposed to soot during the treatment of fire-damaged materials. However, the term
“fire soot” refers to smoke residue on surfaces, a complex mixture of substances that
is often representative of what was in the fire smoke. Fire soot should not be treated
simply as “dirt.”
Put simply, the particle size of smoke residue on a surface can present a respiratory hazard.
The particle size of soot is approximately 2.5 microns, a size that is associated
with deep lung penetration. Particles that are approximately 10 microns or larger get
trapped in the upper respiratory tract. Particles that are 5 microns or smaller can make
it down to the lower lung where the gas exchange occurs in the alveoli. In order to
offer some perspective on the size of these particles, the dust you see flying in the light
coming through a window is about 40 microns in size. Airborne soot present within
the breathing zone of workers is too small to be seen with the naked eye and can
easily be inhaled.
Respiratory hazards connected with exposures when working in an environment that
has been sullied by a fire event differ from those from the past, because the materials
that our belongings are made from have changed over the years. For example, plastics
and other synthetics are much more prevalent in our homes and studios today. It
is important to recognize that these materials undergo pyrolysis during a fire and
become the deposits that are identified as soot.
===Potential Exposures===
Soot is in the general category of airborne particulate matter.
While we would not expect most volatile organic compounds
(VOC) to survive a fire and still be present on the soot, there
may be metals present as well as some chlorinated compounds.
There are not many studies that address what compounds could
be associated with soot particles, essentially using the particles
as a “magic carpet” to get into the lungs. The Phoenix Fire
Department examined this phenomenon during a study focused
on firefighter exposures after the fire was extinguished and
their findings indicated that some chlorinated products become
attached to airborne particulate matter. This is an important
study because it points to the fact that exposure to airborne
vapors and residues during a post-event time frame is much more
complex than our current understanding allows. However, the
important point to glean from this is that soot may be more than
just a particulate hazard; it can potentially carry other chemical
residues that are potentially harmful to the respiratory system.
More research is clearly needed in this area.
Currently, the main health hazards potentially associated with
soot would be irritant hazards. Soot can be both irritating to your
lung tissue and to your skin.
The most common route of exposure during the conservation and restoration process is inhalation due to the proximity of
your breathing zone to your work area. This is assuming that the
work is not occurring under a hood or with some other form of
capture exhaust ventilation.
The second most common route of exposure is self-inoculation. Consider this scenario, you are working on a piece, the
piece is covered in soot, wearing gloves will protect your skin
but what happens when you get an itch in around your eyes or
nose? How clean is the back of your hand or the second knuckle
on your finger?
===How Can You Protect Yourself?===
Protecting yourself from the potential hazards associated with
working soot-contaminated items is simple:
*Do not eat or drink in the area where the soot contaminated items are stored or being restored.
*Wear an air purifying respirator.
*CBRN (chemical, biologica,l radiological, and nuclear) canisters will provide the most protection against chemical vapors and particulates.
*An N95 respirator is appropriate where particulates are the only concern. (Note both types of respirators require annual respirator fit testing.)
*Wear nitrile gloves.
*Do not bring your hands to your face while your gloves are on.
*Wear safety glasses.
*If possible, do all conservation work using a local exhaust or fume extractor such as a chemical hood. (See: Ventilation)
*Use a HEPA/UPLA vacuum to remove the residue from the article.
*Wash your hands thoroughly after removing gloves.
===Perspective===
Most of this article addressed soot hazards under the assumption that the fire soot contaminated article has been brought to
you for conservation treatment. If you are asked to enter a fire
damaged building to conduct an assessment, or commence with
conservation work on fire-damaged materials or other articles
in the building that may be too large to move, the situation is
completely different with regards to what is considered the best
protection for you. Consultation with a health and safety professional is always recommended in these circumstances.
The presence of debris piles that may contain many other
materials will probably present other chemical hazards. For
example, formaldehyde, a known human carcinogen, is found
in the glues that comprise plywood and oriented strand board
(OSB), as well as many plastics, carpets, textiles, and other materials commonly found in typical structure fires. The geometry of
the debris pile can often trap toxic chemicals like formaldehyde
for days. The recommended personal protective equipment for
working in a fire damaged building, includes the following:
• Wear a full-face, air purifying cartridge respirator, equipped with CBRN canisters. These are the only
canister cartridges that offer some protection from formaldehyde. Formaldehyde is one of the most pervasive
toxic chemicals and is found at nearly every fire due to
the content load. Note that organic vapor cartridges will
not work for formaldehyde.
• Wear breathable disposable clothing.
• Wear nitrile gloves.
• Wear safety glasses.
It is important to note that soot is not simply a form of dirt that
needs to be removed from an article. Soot can be a respiratory or
skin irritant, and there may be chemicals or metals riding on the
soot particles that are small enough to enter into your lungs. Be
respectful of what chemical constituents can be represented in
fire soot and take the time to wear personal protective gear.
===Case Study: Studio Precautions When Treating Smoke Damaged Paintings (by Rusin Levenson===
(This article originally appeared in The Hidden Hazards of Fire Soot(AIC News September 2010 (35:5) 1, 3-5))
In the early hours of December 13, 2007, fire erupted in the Harold Golen Gallery
in Miami, Florida. The fire was believed to have started when an advertising
balloon attached to the gallery for Art Basel week came in contact with electrical
wires overhead. Despite the intensity of the fire and the collapse of the ceiling,
178 Pop-Surrealist paintings were rescued from the building. Some of the works
were charred beyond redemption, but 108 of the works were deemed potentially
salvageable and were transported to the Florida branch of the Rustin Levenson Art
Conservation Studio.
Fortunately the warm, dry winter weather allowed the initial treatment of
the works to be undertaken outdoors. The frames and the backing boards were
removed from the paintings and discarded. The paintings were then vacuumed
several times with a vacuum cleaner that was equipped with a HEPA filter. The
reverse of the works, tacking margins, and the stretchers were cleaned with vulcanized rubber sponges. During this part of the operation, conservators wore air
purifying (cartridge) respirators, nitrile gloves, and disposable cover-alls.
Rather than risk contamination of the studio, two rooms in a separate building were isolated for these paintings. One room
was set up for storage, with tarps covering all surfaces and cardboard to interleave the paintings. Tables were set up in an adjacent
room where the treatments took place. Both rooms had individual wall air conditioning units. Portable HEPA air purifying units were installed, one in the storage area, and two in the work room. Filters on all units were changed regularly. Once the
loose particulate matter was removed from the paintings outdoors, they were moved into the prepared spaces for further treatment. Weather permitting, folding tables and easels were used so paintings could be treated outdoors. Conservators wore latex
gloves and air purifying respirators (3M N-95 particulate) during this part of the process.
==References==
The Hidden Hazards of Fire Soot(AIC News September 2010 (35:5) 1, 3-5)
==Further Reading==
Duncan, Teresa T., Edward P. Vicenzi, and Shannon A. Brogdon-Grantham. 2022. “Imaging Rough Paper to Evaluate Methods for Soot Removal.” Microscopy Today 30 (1): 30–33. https://doi.org/10.1017/S1551929521001516.
Category:Health & Safety