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                                SULFURIC ACID
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                                Frank L. Fire
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         Sulfuric acid (also spelled sulphuric acid) is the highest volume
    chemical produced in the world, and is used in more chemical reactions
    and industrial processes than any other chemical. There is a direct
    correlation between the industrialization (or "development") of a
    nation and the amount of sulfuric acid it produces and/or uses.
         Sulfuric acid is used in the manufacture of metals,
    pharmaceuticals, paper, explosives, fertilizers, batteries, cellulose,
    paint, dyes and pigments, detergents, and glue. It is also used in
    leather processing and in the production of numerous other chemicals
    and substances.
         The molecular formula for sulfuric acid, H2SO4, indicates that it
    is a source of the sulfate ion (SO4 -2). Having strong corrosive or
    oxidizing properties, sulfuric acid is the battery acid used in
    automobile shortage batteries and the corrosive material needed to
    unclog sink drains.
         Sulfuric acid is known as oil of vitriol, spirit of vitriol,
    spirit of sulfur, battery acid, diathonic acid, dipping acid,
    fertilizer acid, chamber acid, matting acid, brown oil, hydrogen
    sulfate, nordhausen acid, and G.E. Mat. D4A1.

    APPEARANCE
         Sulfuric acid is a liquid whose color may range from water-clear
    to dark brown. The most common form is at least 98% pure sulfuric acid,
    but it may be shipped in a concentration considered "more than 100%".
    This material is commonly known as oleum, or fuming sulfuric acid.
         Oleum is concentrated sulfuric acid with additional sulfur
    trioxide (SO3) gas dissolved in the acid. When this gas is released, it
    dissolves the moisture in the air, giving the name "fuming" to this
    form of sulfuric acid. Other synonyms for oleum include nordhausen
    acid, disulfuric acid, dithionic acid, and pyrosulfuric acid.
         Both sulfuric acid and oleum are non-flammable liquids, but they
    can cause or support a fire. They can cause a fire by reacting with
    any of a large number of chemicals, liberating enough heat to ignite
    ordinary combustibles. They will support a fire by releasing some of
    the oxygen held in the sulfate ion.
         Sulfuric acid has a specific gravity of 1.54 to 1.84 depending on
    concentration, and is totally soluble in water. It is a relatively
    stable chemical, but may produce fumes if heated. Oleum has a higher
    specific gravity of 1.92 to 1.99, and is also totally soluble in water.
         Both sulfuric acid and oleum will attack many metals, dissolving
    them and liberating their own hydrogen, which is highly flammable. The
    heat liberated during the chemical reaction may be sufficient to ignite
    the hydrogen, producing an explosion.
         Sulfuric acid and oleum are also very reactive with many different
    chemicals and substances, often causing fire and/or explosions.
    Especially dangerous is contact with organic material and oxidizers.
         Sulfuric acid may boil at temperatures ranging from 518~ to 644~
    (again, depending on concentration), and freezes at 37.4~F. It has a
    molecular weight of 98 amu (atomic weight units).
         The appearance of oleum can vary from a colorless fuming liquid
    to a cloudy, or even black fuming liquid. The odor, like that of
    sulfuric acid, is sharp, penetrating, and choking. Oleum has a high
    degree of reactivity with many materials, especially organic and other
    reactive chemicals.

    IDENTIFICATION
         The Department of Transportation (DOT) requires that the black
    and white corrosives placard and label be affixed to containers of
    sulfuric acid and oleum during transportation. The placards show a test
    tube pouring liquid onto metal on the upper left half, and a hand on
    the upper right. The United Nations numerical classification for
    corrosives ("8") is at the lowest point on the placard. The substance's
    specific identification number, a four-digit number preceded by UN or
    NA (UN/NA number), is centered on the card.
         Oleum or fuming sulfuric acid is identified by UN/NA number 1831,
    while sulfuric acid is 1830, and spent sulfuric acid is 1832.
         The STCC (Standard Transportation Commodity Code) for oleum is
    4930030, while sulfuric acid is 4930040, and spent sulfuric acid is
    4930032. The STCC does not appear on the placard, but is used on
    railroads' shipping documents.
         For stationary containers, the National Fire Protection
    Association recommends the use of its 704 Identification System. In
    this diamond-shaped system using four quadrants, the left quadrant
    (colored blue) designates the health hazard, the top (colored red)
    designates flammability, the right (colored yellow) designates
    reactivity, and the bottom (colored white) will have special
    information. For sulfuric acid and oleum, the designation is 3-0-2-W.

    CONTAINERS
         Sulfuric acid is shipped in rail cars, tank trucks, and carboys.
    Although it may be clearly labeled as a powerful corrosive, it may not
    be identified as water-reactive; and there will not be any warning on
    the label indicating that flammable and explosive hydrogen  will be
    generated by the acid contacting many metals.
         Oleum is shipped in the same kind of containers as sulfuric acid.
    It is used mainly in petroleum refining and the manufacture of
    explosives, dyes, and various chemicals.

    HAZARDS
     Personal
         The hazards of sulfuric acid and oleum are similar. Both are very
    corrosive to metals, minerals, and human tissue. Both will produce a
    black char on human skin or wood, as the water is withdrawn from them,
    leaving mostly carbon behind. If either oleum or concentrated sulfuric
    acid contact large areas of human skin, death is sure to result from
    the resulting damage and trauma.

     Water Reactivity
         Sulfuric acid, like oleum, reacts violently with water, liberating
    tremendous amounts of heat. It is an old adage in the chemistry lab
    that a student, while preparing a dilute solution of H2SO4, must NEVER
    add water to the concentrated acid, rather the acid must be added to
    the water. This is because as a water-reactive material, if water is
    added to concentrated sulfuric acid, enough heat will be generated to
    boil the water. If this is done in a container, the water will
    instantly boil away and concentrated sulfuric acid will be forced from
    the container. If the concentrated acid is added to water (in small
    amounts), what will be forced from  the container will be very dilute
    acid, if anything at all comes out.
         This obviously presents a problem to the firefighter responding
    to an incident involving H2SO4. If he must use water on an existing
    fire, or if he must use water to dilute the acid (an acceptable method
    of handling a spill), he has to apply the water in flooding amounts,
    NOT as a stream. A fog or spray application will not splash the acid
    about and will absorb any acid fumes released from the liquid. And, of
    course, any time water is used to dilute a hazardous material, the
    run-off water must be contained.

    PROTECTIVE CLOTHING
         In the event of leaks, spills, and other accidental discharges,
    the techniques for handling incidents involving oleum and sulfuric
    acid are very similar. In all cases, personnel must avoid contact with
    these powerful corrosives. When contact is inevitable, the proper
    safety equipment must be used to prevent contact with the skin or other
    external organs. Needless to say, ingestion of these materials will
    cause serious burns and probable death.
         Safety clothing includes rubber gloves and boots, acid resistant
    goggles and/or face shields, and acid-resistant clothing. Positive-
    pressure, self-contained breathing apparatus (SCBA) must be used at
    all times.
         Acid suits and total encapsulating suits may be constructed of
    nitrile-butadiene, butyl, nitrile, or styrene-butadiene rubber,
    polyvinyl chloride (PVC), neoprene, chlorinated polyethylene, or Viton.
    These suits must be decontaminated after they are used, and care taken
    to contain the cleaning water.
         It is always recommended that the encapsulating suits be tested
    prior to exposure. This can be done by having the suit manufacturer
    provide you with swatches of material from which the suit was made,
    and expose these swatches to the most hazardous material you'll face.
    Concentrated sulfuric acid and oleum surely fit this description.
         Dip a swatch into the acid and leave it there for 15 minutes.
    Remove the swatch and carefully wash it clean with water. Inspect it
    for damage. Admittedly this is a severe test, but your life may depend
    on the suit getting a passing grade.

    HANDLING
         Once these corrosives have been released from their containers,
    first responders should never make any attempt to handle the materials.
    Also, if carboys or bottles of the acids have been damaged, these
    containers should not be handled unless the proper protective equipment
    is worn, which, at the very least, includes acid-resistant goggles and
    face shields, and rubber aprons and gloves.
         Whenever possible, let personnel with the most experience in
    handling these materials move the containers around. That is, wherever
    it is not necessary for emergency personnel to be involved, such as in
    cleanup, let others who have more experience do the non-emergency work,
    such as shippers, consignees, etc.
         There are several ways to handle a sulfuric acid and/or oleum
    incident, including containment, absorption, re-cycling, dilution,
    neutralization, and removal. Never forget that one of the possible
    responses to a leak or spill is to do nothing as far as intervening in
    the incident. Your best response may be to just seal off the area and
    wait for the experts to arrive. In any case, whether you directly
    intervene or not, the implementation of evacuation procedures should
    always be considered.

    CONTAINMENT
         Containment techniques, of course, include all actions that will
    keep the released material from moving to an area where it will cause
    more problems than the original incident. Even though these techniques
    appear to be simple, you must keep in mind that you are still dealing
    with very dangerous substances, and simple containment does not bring
    the incident to a successful conclusion.
         The simplest containment technique for a release of sulfuric acid
    or oleum on land is to build a dike to surround the material. This dike
    may be constructed of soil, sand, or other inert materials. Soil may
    be the choice simply because of its presence. Other inert materials may
    include sorbents (mentioned later), but if the spill is large, there
    may not be enough sorbent material readily available to do the job.
    Another technique is to dig a pit with trenches leading from the
    liquid to the pit. Here, the soil removed to make the pit may be used
    as diking material also.
         Be advised that these containment techniques enable the acid to
    seep into the ground, and this may complicate the removal of all
    contaminated soil (including diking material), which is necessary
    under any circumstances.
         Containment of dangerous fumes generated by a spill may be
    effected by the use of a fog stream. This technique will dissolve acid
    vapors from the air. Also, water may be used to dilute the material;
    however, whenever water is used, remember the violent reaction that
    will occur when oleum or concentrated sulfuric acid comes in contact
    with water. Again, with powerful corrosives like sulfuric acid and
    oleum, all water that is used in the incident must be contained or
    otherwise prevented from entering a sewer, stream, or other waterway.
         If the acids spill into a waterway, containment is much more
    difficult, since both materials are soluble in water in all
    proportions. Total damming of the stream or river is necessary to
    prevent contamination downstream. However, since this is rarely
    possible, all users of the water downstream must be notified of the
    contamination so that they may be able to divert the flow.

    ABSORPTION
         The released liquid may be absorbed with inert materials, such as
    soil, sand, clay, powdered cement, fly ash or a commercial sorbent. If
    any of the acid can be removed before absorption is tried, it will
    naturally lessen the amount of sorbent required.
         Remember, absorption, like containment, is not the final step in
    handling the incident. The hazardous material is still present. All
    you have done is render it immobile by getting it to adhere to the
    surface of another material. Like the contaminated soil and/or diking
    material in the containment procedure, the sorbent that holds the acid
    must now be removed.

    DILUTION
         A third method of handling a spill of these acids is to dilute
    them with water (remember what happens when water contacts sulfuric
    acid and/or oleum?). Of course, this means that you will need a very
    large containment area or pit to hold the diluted acid. You must never
    allow the dilute solution to enter sewers or waterways, or the
    contamination that you are trying so hard to prevent will spread. You
    may have to use water in a volume of 1,000 times the volume (or more)
    of the spilled material to get the acid to a concentration where it no
    longer poses a hazard. Then a decision must be made concerning what to
    do with the dilute solution. Leave this decision to the environmental
    representative, who will surely have responded to the incident.

    NEUTRALIZATION
         Neutralization is a chemical reaction that will change the
    hazardous chemical to a usually nonhazardous material and water. For
    acids, there are several neutralization agents that may be used, and
    they all have drawbacks:
         - Sodium hydroxide (caustic soda) or potassium hydroxide (caustic
           potash), both in a concentrated solution in water, will be the
           most effective, but they are expensive, and are very hazardous
           materials themselves.
         - Calcium hydroxide (slaked lime) dissolved in water is not as
           dangerous to use as the sodium and potassium hydroxides, but it
           is fairly costly and not as effective. All three hydroxides may
           be used in their dry, solid form, but they are very hazardous in
           this state and will not mix as rapidly as the solutions will.
         - Sodium bicarbonate (baking soda), sodium carbonate (soda ash),
           and calcium carbonate (crushed limestone) are usually
           recommended because they are relatively inexpensive (calcium
           carbonate is the least expensive and the least effective, but
           works adequately) and they will do the job. With the addition
           of these materials, there will be visible bubbling and gassing.
           This is the generation of carbon dioxide, a product of the
           neutralization process.
         In any event, a small sample of the spilled acid should be
    obtained in a small container, and the chosen neutralizer should be
    added slowly. This simple experiment will show what will happen when
    large amounts are added to the spill, and will eliminate any surprises.
    The use of acid test paper will also indicate the relative amount to
    be added to the spill.
         Once again, the ranking environmental representative should make
    the decision that the spilled acid has been rendered safe.

    RECYCLING
         Recycling is a useful technique if the container holding the acid
    is leaking in such a way that the released material can be caught in a
    container and pumped back into the leaking container. This creates a
    relatively closed system that will keep the material under control
    until the acid may be off-loaded into another container.
         Just be sure that the container catching the leaking acid is
    resistant to the acid, along with all parts of the pump with which the
    acid will come in contact.

    REMOVAL
         The safest procedure for incident responders is for the shipper
    (or manufacturer, or consignee) to provide another container and
    equipment to move the acid from its original container. If the acid
    has spilled and is behind containment dikes, in a pit, or in another
    container, the shipper would then pump it into a secure container. if
    the material has been absorbed, the shipper would then remove all the
    contaminated sorbent, including all contaminated soil.
         The remover of the acid or contaminated sorbent and/or soil
    should be either the chemical manufacturer, consignee, shipper, or a
    professional firm that is a recognized expert in the chemical field.

    EVACUATION
         Depending on the size of the spill, the geographical location,
    population, the ability to effect one of the emergency responses, and,
    of course, the weather, evacuation may be necessary for as far as a
    one-half mile radius and up to two miles downwind.

    FIRST AID
         In the event the chemical contacted the eyes and/or skin, flood
    the affected area with water for 15 minutes (holding the eyelid open
    during the washing). For ingestion, large amounts of water must be
    administered. For inhalation of vapors and fumes, the airway must be
    maintained and resuscitation measures used. Treat for shock and
    pulmonary edema. Get medical attention immediately.

    DECONTAMINATION
         Decontamination of protective clothing should be done so that the
    run-off water can be contained. The encapsulating suit or other
    impervious protective clothing should be washed down thoroughly:
          - First with clean water,
          - Then by a rinsing with a solution of sodium bicarbonate and
            water,
          - Another clean water rinse,
          - A washing with a solution of a mild detergent,
          - And a final clean water rinse.
         Only the water from the first washdown needs to be contained.

    FINAL CLEANUP
         The final cleanup should be carried out by the shipper, the
    manufacturer, the consignee, or other professional organizations
    experienced in removal of hazardous materials. This work should be done
    under the supervision of the proper environmental officials.
         In all hazardous material incidents, the fire department and other
    first responding personnel should limit their activities to emergency
    procedures only, and not be involved in clean-up and removal
    procedures. Leave this work to the "experts".



    The above was taken from:
    Fire Engineering  June  1986
    Chemical Data Notebook Series # 1

 
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