Some of the less routinely used products which contain flammable solvents include:

• Dykem Blue metal marking compound,
• assorted epoxy resins,
• assorted spray enamels and coatings,
• enamel paints,
• Frekote mold release compounds (contains dibutyl ether, flash point 1331/4),
• PVC pipe cement,
• turpentines and paint thinners.

Acetone has a low flash point and is presents a severe flammability hazard. Ethyl alcohol can also readily form flammable or explosive mixtures with air. Isopropyl alcohol is somewhat less flammable than acetone or ethyl alcohol. Products containing flammable solvents, especially some of the mold release compounds and aerosol spray enamels, may present severe flammability hazards in the presence of an ignition source.

Scope

This procedure covers employee all uses of flammable organic solvents and products containing such solvents within the PSFC.

Safety Analysis

Failure to follow this procedure could result in primary skin and eye irritation from direct contact with organic solvents; skin defatting or dermatitis from prolonged or repeated skin exposure (when the skins' fatty layer is damaged, one becomes more susceptible to dermatitis, and chemicals are more readily absorbed through the skin); central nervous system depression or chronic toxic effects, such as liver or kidney effects, from inhalation of high concentrations of solvent vapors; or the creation of fire and explosion hazards.

Definitions

Primary Irritant - A primary irritant causes reaction by direct contact with the skin, eyes, or respiratory system if the concentration and exposure time are sufficient.

Skin Defatting Agent - A skin defatting agent causes deterioration of the fatty layer of the skin with prolonged or repeated contact.

Flammable - A flammable liquid is one which has a relatively low flash point. All ClassÊI flammable liquids have a flash point below 100^o F. Class II flammable liquids have a flash point below 140^o F, and Class III flammable liquids have a flash point above 140^o F.

Flammable or Explosive Limits - The minimum and maximum concentrations of a gas or vapor in air within which a substance will explode or burn when exposed to a ignition source.

Flash Point - The flash point is the lowest temperature at which a liquid gives off enough vapors which, when mixed with air, can be easily ignited by a spark. The lower the flash point, the greater the risk of fire or explosion.

Flash Back - When the vapor density of a solvent is heavier than air, solvent vapors from a source such as a leak or spill may travel a long distance along the floor level from the release site. If these vapors reach an ignition source, the resultant combustion may "flash back" to, and ignite, the original source.

Oxidizer - A compound that spontaneously evolves oxygen at room temperature or under slight heating. Oxidizers present a fire risk when they come into contact with organic materials.

Responsibilities

The supervisor or responsible person shall designate and train employees who use flammable solvents or products which contain flammable solvents. The supervisor or responsible person shall ensure that necessary supplies are available to clean up spills of such materials. The supervisor or responsible person shall ensure that all flammable solvents and products which contain flammable solvents are used in accordance with good work practices in adequately ventilated areas.

Assumptions

The supervisor or responsible person shall be familiar with the hazards associated with the handling, use, and storage of flammable solvents and products containing flammable solvents and appropriate spill and emergency procedures described in this document.

Flammable solvents or products containing flammable solvents shall only be used in hoods or areas specifically designated areas for their use.

Required Supplies

• Flammable liquid storage cabinets. Approved flammable liquid storage cabinets may be necessary depending on the quantity of stock flammable solvents which needed to be on-hand, and the amount of flammable liquid waste generated.

• Secondary containers. All glass containers of flammable liquids shall be stored in secondary containers. It is preferred that all 1 gallon or greater containers be of metal, polypropylene, or plastic coated over glass.
• Protective gloves. The lightweight PVC gloves used during light cleaning, assembly, and coating operations should be sufficient to prevent skin contact with small quantities of solvent. Heavier Nitrile gloves are required for cleaning up spills and are always required whenever the hands or fingers must be immersed in the solvent. The Nitrile gloves provided by the PSFC provide adequate protection against alcohols, but are degraded by acetone. Any gloves which are dirty or which have been penetrated by solvent should be discarded.
• Glasses. Safety glasses are necessary for most solvent operations. Employees who do not wear glasses or who wear contact lenses must be provided with splash-proof chemical goggles or face shields when handling flammable solvents. Contact lens wearers shall always wear splash-proof goggles when handling solvents.
• Face shields. Face shields may be necessary when there exists the potential for splashes or explosions from use of large quantities of solvents.
• Spill materials. Paper towels or adsorbent materials such as spill control pillows , and chemical resistant gloves (Nitrile are provided). Where quantities of flammable solvents can produce an explosive mixture with air in the laboratory, special absorbent materials such as activated carbon (available through Lab Safety Supply) must be considered to eliminate the explosion hazards.

Procedures

1. General Procedures
   1. Read the Material Safety Data Sheets for the solvents to be used prior to initial use of the solvent.
   2. Flammable liquids shall not be stored together with oxidizing agents including potassium permanganate, bleach, nitric acid, and peroxides.
   3. Flammable liquids in containers with a capacity greater than 500 ml shall be stored in approved, flammable liquid storage cabinets or other designated storage areas.
   4. Flammable solvent work must be done in a hood or specifically designated area. Never use any solvents in confined areas, such as cavities large enough to require placing the head and shoulders inside the cavity, tanks, vessels, pits, or any other poorly ventilated, confined area. If such work is required, ask the supervisor to review the proposed procedure.
   5. Prior to initiating work, ensure that there are adequate paper towels, spill control pillows, or other appropriate absorbent materials on-hand in the event that a spill occurs. When using quantities of flammables which can generate an explosive mixture in the area of use, obtain special absorbents which absorb the flammable vapors to eliminate the explosion potential.
   6. Review the area for ignition sources. Live electrical circuits, electric sparks, propane torches, welding activities, and hot surfaces are all potential ignition sources. No activities which present a likely ignition source, such as brazing with a propane torch, may be performed in the vicinity of operations using flammable solvents.
   7. Most solvents cause mild to severe eye irritation, but do not cause irreversible eye injury. An eyewash should be located nearby to flush the eyes in the event of eye contact to minimize potential discomfort and irritation.

   8. Ensure that gloves and eye protection are worn where required.

2. Specific Uses
   1. Using a 500 ml squeeze bottle:
      • Perform cleaning inside a laboratory fume hood whenever possible. Where appropriate, use a drip pan to collect any run-off. When the cleaning is complete, allow the workpiece and any wiping materials such as paper towels or lint-free cloths to evaporate to dryness in a laboratory fume hood. Do not place any towels or rags into the trash unless they are completely dry.
      • Do not allow the excess solvent which has been collected in a drip pan to evaporate to dryness in the fume hood. Place the used solvent in a designated, properly labeled waste container. Do not mix different kinds of solvents in waste containers unless instructed to do so by the supervisor.
   2. Submersive cleaning in trays or pans:
      Submersive cleaning in trays or pans shall be performed inside a laboratory fume hood whenever possible. If a fume hood is not available, such procedures shall be performed in an open, well-ventilated area. A label shall be affixed to any container used for this purpose, indicating the identity, flammability, and health hazards of the solvent. Pre-printed labels for specific solvents are available from the ES&H Office. If this is not possible because cleaning of the outside surface of the container is required, a sign may be placed next to the container indicating this information.
      • The only exceptions to the labeling requirement are:
        1. if solvent is dispensed from a labeled container into a secondary container for the sole, immediate use of the person dispensing the chemical during that work shift, and
        2. the container will not be left unattended where other people may come into contact with it.
      • When the cleaning is complete, allow the workpiece and any wiping materials such as paper towels or cloths, to evaporate to dryness in the laboratory fume hood.
      • Do not allow the waste solvent to evaporate to dryness in the fume hood. Place the used solvent in a designated, properly labeled waste container. Do not mix different kinds of solvents in waste containers unless instructed to do so by the supervisor.
   3. Cleaning oil-containing equipment (e.g., vacuum pumps, hydraulic systems, motor-driven equipment) during oil changes outside of a laboratory fume hood:
      • Often the outside surfaces of equipment become contaminated with oil when such equipment is drained in order to change the oil. This can be minimized by carefully following the manufacturer instructions for draining the oil. In any event, drain as much oil from the equipment as possible BEFORE cleaning the outside surface with solvent.
      • If it appears that it will be necessary to clean the outside surface of the equipment by washing it with solvent, OBTAIN A SUFFICIENTLY LARGE DRIP PAN TO CATCH the solvent run-off. Do not collect the solvent run-off in the same drip pan with the oil. If necessary, empty the oil into an appropriate waste oil container, and wipe the excess oil from the drip pan prior to squirting solvent onto the equipment. Where possible, use paper towels or cloths wetted with the solvent to wipe off the equipment, rather than squirting it directly with the solvent.
      • Allow contaminated paper towels or clothes to evaporate to dryness in a laboratory fume hood. Place the used solvent in a designated, properly labeled waste container. If the waste solvent is heavily contaminated with oil, do not mix it with cleaner waste solvents. Obtain guidance from the supervisor if necessary.
   4. Use of solvents in ultrasonic cleaners -beaker capacity units:
      • Place the solvent and the part to be cleaned into a beaker and place the beaker in the ultrasonic cleaner bath. Make sure the ultrasonic cleaner is filled with the appropriate medium. Turn the ultrasonic cleaner on and operate until the part is sufficiently cleaned. Remove the part while the ultrasonic mechanism is still operating. When finished, immediately place the waste solvent into a designated, properly labeled waste container. Do not leave an unlabeled beaker containing solvent in the ultrasonic cleaner.
   5. Use of solvents in ultrasonic cleaners -up to one gallon capacity units:
      Solvents shall be transferred by pouring from 1 gallon containers. Larger volumes of flammable solvents shall not be transferred unless proper bonding and grounding has be done to prevent arcing of static charge. Flammable solvents shall not be used in larger capacity units without permission from the ES&H office.
      • Place the part into a basket or other holding device and submerge into the solvent reservoir. When the parts are clean, raise the basket slowly while the ultrasonic mechanism is still operating. Hold the basket so that the excess solvent drips back into the reservoir. Allow the parts to dry in an area equipped with local exhaust ventilation, if possible. When finished, turn off the ultrasonic mechanism and cover the reservoir with a fitted lid.
      • Do not allow excess solvent to evaporate to dryness. If the cleaning will not be repeated soon, the solvent shall be removed from the ultrasonic cleaner by scooping or pouring into a designated, properly labeled waste or re-use container.
   6. Use of Frekote and other flammable liquid mold release compounds:
      • Mold release compounds shall be used inside of a laboratory fume hood whenever possible. Pour the required amount of Frekote or other mold release compound (up to 50 milliliters) into a 250 milliliter glass beaker labeled with the chemical identity, and the flammability and health characteristics of the release compound. If this is not feasible, a tag shall be attached to the container. Apply the mold release compound with a paint brush. When finished, tightly cover the beaker with the brush in it using aluminum foil and store in the laboratory fume hood for future use or transfer the excess liquid to a designated, labeled container. Allow the mold to dry in the fume hood for one hour. Return the Frekote container to its proper storage location.
   7. Use of aerosol sprays containing flammable solvents:
      Users shall read the labels on aerosol cans and be aware of the hazardous components of such products. Extra care shall be taken to ensure that there are no ignition sources present when using these products.
      • Spray aerosols shall be used inside laboratory fume hoods whenever possible, and their use outside of a laboratory fume hood shall be minimized.

Training

The supervisor shall supply this procedure to affected employees along with the MSDS for the material to be used and verify that they understand it. Employees should understand the health and flammability characteristics of routinely used flammable organic solvents.

Spill Procedures:

The major hazard of large spills is the potential release of hazardous concentrations of flammable vapors. Therefore, in the event of a large spill of the material, (i.e., one gallon container), shut off any ignition sources, and call the Industrial Hygiene Office at 3-2596. If there is personal injury or a strong threat of personal injury, dial 100. Do not let anyone enter the spill area. Employees shall restrict access to the work area and dial 100.

Small spills may be absorbed or wiped up using paper towels. After absorbing any excess liquid, clean-up materials should be placed in an approved metal container with a self-closing lid.

Special absorbent materials are available which absorb the flammable vapors of solvents. They considerably reduce the potential for explosion of flammable vapors. Use of these materials should be considered when developing spill response procedures. If none are available in the immediate vicinity, emergency supplies can be obtained from NW21-167.

Waste Disposal Procedure

Organic solvents may not be disposed of by pouring int drains or by allowing them to evaporate into the air.

Empty aerosol cans which had contained flammable solvents may be placed in the trash.

Used material may be accumulated in a labeled container in the immediate work area until the container is full or the work is complete. It must be stored appropriately during accumulation with the cap on. It must be inside a secondary container so that uncontrolled spills cannot occur, separated from incompatible materials. Once the container is full, proceed as follows:

1. Obtain a red "Hazardous Material Tag" from ES&H or the MIT Safety Office. Fill it out with the name of the material in English (no chemical formulae). Include any major contaminants which are present in the waste. Include the name of the lab and your name, or the name of the PI, and the date

2. If the material is commercially prepared product sold under a tradename, provide an MSDS (these are shipped with the product, and can be easily obtained from the manufacturer if lost.

3. Take it to a hazardous waste accumulation area and place in the designated tray. Make sure that the waste is placed in an accumulation area within 3 days of designation.

4. Enter the chemical name on the waste packing list at the accumulation area along with the other required information such as amount and hazard.

5. Call the Safety Office (3-4736) and ask them to come to the waste accumulation area and pick up the waste.

Unused flammable solvents which are no longer needed should be left in the original containers. Disposal should proceed as in the previous section.

Unneeded epoxy resins containing flammable solvents should be mixed according to the manufacturer's directions, allowed to harden, and placed in the regular trash.

First Aid Procedures

In the event of skin contact, the affected area should be washed with soap and water (preferably the pink lanolin containing liquid soap). Contaminated clothing should be removed since wet clothing may hold chemicals in contact with the skin. If skin irritation or dermatitis develops, the affected employee shall be examined at the Medical Department.

In the event of eye contact, flush the eye of the affected employee with water. The affected employee shall be examined by the ophthalmology clinic at the MIT Medical Department.

If an employee has lost consciousness, dial 100 (or 911 if offsite) for emergency medical assistance.

If an individual accidentally ingests a flammable solvent, dial 100 (or 911 if off site) for immediate transport to the MIT Medical Department for examination.