|
SECTION 7: Safe Work Practices and Procedures
7D: Corrosive
Materials
Many chemicals commonly used in the laboratory are corrosive or irritating
to body tissue. They present a hazard to the eyes and skin by direct contact,
to the respiratory tract by inhalation or to the gastrointestinal system
by ingestion. Anecdotes offers incidents
involving chemical burns from incorrectly handling corrosives.
Corrosive Liquids
(top)
Corrosive liquids (e.g. mineral acids, alkali solutions and some
oxidizers) represent a very significant hazard because skin or eye contact
can readily occur from splashes and their effect on human tissue generally
takes place very rapidly. Bromine, sodium hydroxide, sulfuric acid and hydrogen
peroxide are examples of highly corrosive liquids. See Chemical
Specific Issues for specific corrosive liquids such as Hydrofluoric
Acid and Phenol.
The following should be considered:
1. The eyes are particularly
vulnerable. It is therefore essential that approved eye
and face protection be worn in all laboratories where corrosive chemicals
are handled.
2. Gloves and other chemically
resistant protective clothing should be worn to protect against skin
contact.
3. To avoid a flash steam explosion due to the large amount of heat evolved,
always add acids or bases to water (and not the reverse).
4. Acids and bases should be segregated for storage.
5. Liquid corrosives should be stored below eye level.
6. Adequate quantities of spill control materials should be readily available.
Specialized spill kits for acids and bases are available through most
chemical and laboratory safety supply catalogs.
Corrosive Gases and
Vapors (top)
Corrosive gases and vapors are hazardous to all parts of the body; certain
organs (e.g. the eyes and the respiratory tract) are particularly sensitive.
The magnitude of the effect is related to the solubility of the material
in the body fluids. Highly soluble gases (e.g. ammonia, hydrogen chloride)
cause severe nose and throat irritation, while substances of lower solubility
(e.g. nitrogen dioxide, phosgene, sulfur dioxide) can penetrate deep into
the lungs.
- Warning properties such as odor or eye, nose or respiratory tract
irritation may be inadequate with some substances. Therefore, they
should
not be relied upon as a warning of overexposure.
- Perform manipulations of materials that pose an inhalation hazard
in a chemical fume hood to
control exposure or wear appropriate respiratory protection.
- Protect all exposed skin surfaces from contact with corrosive
or irritating gases and vapors.
- Regulators and valves should be closed when the cylinder is
not in use and flushed with dry air or nitrogen after use.
- When corrosive gases are to be discharged into a liquid, a trap,
check valve, or vacuum break device should be employed to prevent
dangerous
reverse flow.
Corrosive Solids
(top)
Corrosive solids, such as sodium hydroxide and phenol, can cause burns to
the skin and eyes. Dust from corrosive solids can be inhaled and cause irritation
or burns to the respiratory tract. Many corrosive solids, such as potassium
hydroxide and sodium hydroxide, can produce considerable heat when dissolved
in water.
- Wear gloves and eye protection when handling corrosive solids.
- When mixing with water, always slowly add the corrosive solid
to water, stirring continuously. Cooling may be necessary.
- If there is a possibility of generating a significant amount of
dust, conduct work in a fume hood.
 Section
7E: Compressed Gases
 Section
7C: Peroxide Forming Compounds and Reactives
|
