VI. CHEMICAL HAZARDS
A number of routine procedures in a laboratory involve the use of hazardous chemicals. They must be appropriately labeled to indicate the hazards. Read the labels and observe the precautions.
Hazardous chemicals may be grouped as follows:
Corrosive or Caustic: Acids and alkalis may cause burns of the skin, mouth, lungs, or eyes and irreversible damage to equipment and storage areas. The US EPA defines corrosive as having a pH less than 2 or greater than 12.5.
Toxic Chemicals: Almost any substance in sufficient quantity can be considered toxic. Toxic chemicals are those that damage biological structure and function through exposure or accumulation in tissues. Usually, this involves relatively small amounts of the toxin.
For these purposes, a poison will be defined as a substance that may cause death or serious health effects if relatively small amounts are inhaled, ingested or absorbed by the skin. Poisons may be gas, liquid or solid.
Specific authoritative sources such as the Registry of Toxic Effects of Chemical Substances (RTECS), 29 CFR Part 1910 Sub-part Z, the National Toxicology Program (NTP) Annual Report on Carcinogens, the US EPA, and the International Agency for Research on Cancer (IARC) monographs serve as primary sources of toxic chemical information.
Flammables: Materials that may easily ignite, burn and serve as fuel for a fire. The US EPA defines flammable as having a flash point less than 140 degrees Fahrenheit.
Reactives: Materials that may release large amounts of energy under special circumstances. Readily undergoes violent change; forms explosive mixtures or toxic gases with water; capable of detonation.
A. Caustics and Corrosives
Contact with the skin or eyes represents the greatest risk when dealing with corrosives. Match the hazard presented by the material with which you are working with the protective equipment recommended by the MSDS. Always wear resistant gloves and eye protection when dealing with corrosives. In some cases, respiratory protection may be desirable (contact the Environmental Health & Safety Office for information on the Respiratory Protection Plan).
a. Be aware of the nearest eyewash station and safety shower for your work location.
b. When acids or alkalis are used, some form of containment to control spills must be employed. Included among these methods are bench top spill diapers and resistant trays.
c. Do not pipette by mouth. Use a mechanical or vacuum-assisted pipette aid.
d. When diluting, always add ACID to WATER, never add water to acid. Allow the acid to run down the inside of the container and mix slowly by gentle rotation.
e. Be aware of the methods, materials and procedure for cleaning corrosive spills. In the event of a spill beyond your immediate ability to control, notify University Police (x6666). (See Appendix E)
a. Store corrosives in a cool, dry and well-ventilated area away from direct sunlight.
b. Use storage materials that are resistant to corrosion.
c. Store caustic and corrosive materials near, but not on the floor to minimize danger of bottles falling from shelves.
d. Large amounts of corrosive chemicals require a dedicated corrosive storage cabinet.
e. Segregate acids from bases. Store chemicals according to their primary hazard classification.f. Acid bottle carriers must be used for containers over one quart in size.
Isolate corrosives from the following:
- toxic materials
Separate containers to facilitate handling. Organic acids are to be store separately from strong oxidizing agents to prevent interaction of fumes and corrosion of storage cabinets.
General First Aid Considerations for Corrosives
In the event that a corrosive contacts the skin, immediately remove any contaminated clothing and flush the area with copious amounts of water. Use care not to rub or damage the skin. Notify your supervisor and seek medical attention.
In the event that a corrosive chemical contacts the eyes, immediately flush the eyes with large amounts of clean water, including under the eyelids for at least 15 minutes. Seek immediate medical attention.
DO NOT WEAR CONTACT LENSES WHEN WORKING WITH CORROSIVE MATERIALS!
If a corrosive material is ingested, DO NOT induce vomiting. Seek immediate medical attention.
B. Toxic Chemicals
- Handling and Storage
a. Isolate, segregate, and clearly label all toxic chemicals.
b. Adequate room ventilation must be provided at the work site area. A fume hood must be used whenever possible.
c. The appropriate personal protective equipment must be worn as directed by the label or MSDS. If in doubt, contact the Chemical Hygiene Officer.
d. Limit exposure time.
e. Practice good personal hygiene.
- hand washing
- wearing a lab coat
Special consideration must be given to this poison that is used in many laboratories at the College.
Use care to avoid spills of elemental mercury.
CLEAN UP SMALL GROSS spills with a pipette or “Sweeper.” Ventilate area well to remove mercury vapors. Large spills (>1 ml) should be referred to the Environmental Health & Safety Office. (x6666)
Chronic exposure and absorption of mercury may lead to a metallic taste in mouth, a gray line around gums and neurological problems.
Do not place elemental mercury waste in drains. Contact the Chemical Hygiene Officer for proper disposal.
Due to its toxicity and difficulty of disposal, the purchase of mercury and mercury containing items is restricted. (See appendix A)
Carcinogens are hazardous chemicals capable of increasing the risk of cancer(s) through exposure, usually over time. Teratogens are hazardous chemicals capable of causing an increased risk of birth defects in children of exposed workers.
Prudent practices need to be used in dealing with known or suspected carcinogens and teratogens. Reduce your exposure to these chemicals to the lowest possible level through good work habits and common sense.
The greatest potential harm is a result of repeated or prolonged exposure to these chemicals in excess of the acceptable limits.
Other behaviors such as diet and smoking can contribute to the synergistic or antagonistic effects of carcinogenic materials.
Plan ahead for problems with carcinogenic compounds. A protocol should exist for handling, storing, disposal and emergency procedures to be followed.
Flammable chemicals represent a major safety concern at the College because of the immediate physical danger that these materials present to all employees. Our primary interest is in reducing the chance of fire involving these materials. Also, many flammable chemicals have associated health risks.
- Handling and Storage
a. Use small volumes of solvents/flammables (100 ml or less) when performing routine tasks. Store larger amounts in approved flammable containers. Never store flammables with reactive chemicals or oxidizers.
b. Transfer solvents/flammables in a working laboratory hood or well-ventilated area. Smoking, open flames, and other sources of ignition are not permitted around solvents.
c. Use solvents at temperatures 10 to 15 degrees below their flashpoint, if possible.
d. Grounding must be provided on all large drums used for storage or dispensing of solvents. All containers must be labeled.
e. Note the location and type of fire fighting equipment available for the particular need. Flammable liquid fires are Class B fires. Extinguishers that are effective on class A, B, & C fires are available throughout the College.
f. Remember that flammable liquids may have other health consequences as well. Prudent practices need to be observed in storing and disposing of flammable liquids.
g. Quantities of more than one gallon must be stored in a safety can. If a reagent must be stored in glass for purity, the glass container should be placed in a bottle carrier to lessen the danger of breakage.
h. Small quantities (working amounts) may be stored on open shelves, but bulk storage (more than one gallon) must be in a designated flammable storage area.
i. Approved flammable storage cabinets will be needed for laboratories with a large inventory (10 gallons or more) of flammable chemicals.
- Refrigeration and Cooling Equipment
The use of domestic refrigerators for the storage of solvents and flammables presents a significant hazard to the laboratory work area. This practice is prohibited at the College of Environmental Science and Forestry.
Only FM or UL approved “explosion-proof” or “laboratory safe” refrigeration equipment may be used for flammable materials. Explosion-proof refrigeration equipment is designed to protect against ignition of flammable vapors both inside and outside the refrigeration compartment. “Laboratory Safe” provides protection only on the inside.
Every laboratory refrigerator must be clearly labeled to indicate whether or not it is acceptable for storage of a flammable material. The required labels are available through the Chemical Hygiene Officer.
Reactive chemicals are characterized by their tendency to release large amounts of energy under certain conditions. Since the catalyst for these reactions frequently is found in the normal environment, special precautions need to be observed to safely use and store these materials. Included in this category are explosives, water reactive materials, air sensitive materials, and mixtures of oxidizing and reducing agents.
- Handling and Storage
a. Ensure adequate protection against shock, extremes in temperature, other reactive chemicals, and potential sources of ignition.
b. Segregate oxidizers from reducers. Store reactive chemicals according to their primary hazard classification.
c. Isolate reactive chemicals from toxic materials and flammables.
d. Use adequate personal protective equipment. Many reactive chemicals liberate toxic fumes or gases. Small, easily managed amounts must be used in a ducted fume hood.