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The National Fire Protection Association - NFPA uses a symbol system designed as a diamond-shaped label containing four differently colored squares. A number (0 - 4) or an abbreviation is added to each square indicating the order of hazard severity. The higher the number, the greater the hazard.
Red Background Flammability
- 4 - flash point < 73 oF
- 3 - flash point < 100 oF
- 2 - flash point
> 100 oF < 200 oF
- 1 - flash point > 200 oF
- 0 - will not burn
Yellow Background Reactivity
- 4 - explosive at room temp
- 3 - shock and heat may detonate
- 2 - violent reaction with water
- 1 - unstable if heated, not violent
- 0 - not reactive with water
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Blue Background Health Hazard
- 4 - deadly
- 3 - extreme danger
- 2 - hazardous
- 1 - slightly hazardous
- 0 - normal material
White Background Specific Hazard
- oxidizer OX
- acid ACID
- alkali ALK
- corrosive CORR
- use NO WATER
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Flammable Materials:
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- Flammability is a measure of how easily a gas, liquid, or solid will ignite and how quickly the flame, once started, will spread. Flammable liquids themselves are not flammable; rather, the vapor from the liquids are combustible.
- The flash point of a material is the temperature at which a liquid (or volatile solid) gives off vapor in quantities significant enough to form an ignitable mixture with air. Given an external source of ignition (i.e., spark, flame), a material can ignite at temperatures at or above its flash point.
- Pyrophoric materials can ignite spontaneously with no external source of ignition. For instance, the Group 1 metals on the periodic table react with water to produce hydrogen and heat. Often this heat is enough to ignite the hydrogen.
- Examples of commonly-used flammable chemicals:
- acetone
- hydrogen
- ethyl ether
- sodium
- ethyl alcohol
- acetylene
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Carcinogens:
- A carcinogen is an agent capable of causing cancer, as designated by the Occupational Safety and Health Administration (OSHA). Long-term exposure to carcinogenic substances can result in cancers of various types. A number of substances have been found to be capable of producing cancer following exposure by inhalation, ingestion, or skin contact.
- Known carcinogens should not be used by students in our high school lab.
- The following terms are used to describe carcinogenic materials:
- Sufficient positive -- Those chemicals that were found to promote and increase incidence of malignant tumor in a multiple species or strain of lab animals.
- Limited positive -- Those chemicals found to promote either malignant tumors in a single strain, or benign tumors in single or multiple species or strain.
- Inadequate -- Insufficient evidence to make a decision.
- Equivocal -- Almost no supporting evidence.
- Negative -- (limited or sufficient) significant negative evidence.
- Examples of known or suspected high risk carcinogens:
* Designates an EPA controlled substance.
- 4-Nitrobiphenyl
- Methylchloromethyl ether
- 3,3'-Dichlorobenzidine *
- Chloroform *
- Benzidine *
- Benzene *
- Vinyl chloride *
- Arsenic
- Formaldehyde *
Mutagens:
- Mutagens are chemical and physical agents that induce mutations in DNA and in living cells. This affects the genetic system in such a way as to cause cancer or hereditary changes in chromosomes. Individuals exposed to chemicals with mutagenic properties may develop genetic damage to the extent that future offspring will be affected.
- Known mutagens should not be used by students in our high school lab.
- Examples of Mutagens:
- Arsenic
- Ethidium Bromide
- Ionizing Radiation (gamma, x-rays)
- Alkylating agents (e.g., dimethyl sulfate)
Teratogens:
- Teratogens are chemical and physical agents that interfere with normal embryonic development. Teratogens differ from mutagens in that there must be a developing fetus. Damage to the fetus (embryo) is most likely to occur early in pregnancy, during the first 8 - 10 weeks. Teratogens may produce congenital malformations or death of the fetus without inducing damage to the pregnant woman.
- Known Teratogens should not be used by students in our high school lab.
- Three identified Teratogens:
- Dibromochloropropane
- Lead
- Ethylene oxide
- Other materials associated with reproductive health disorders:
- Antimony
- Carbon disulfide
- Polychlorinated biphenols (PCBs)
- Nitrous oxide
- Formaldehyde
- Ethylene dibromide
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Corrosive Materials:
- Corrosive chemicals can burn, irritate, or destructively attack living tissue. When inhaled or ingested, lung and stomach tissue are affected.
- Materials with corrosive properties can be either acidic (low pH) or basic (high pH).
- Corrosive gases -- are readily absorbed into the body through skin contact and inhalation.
- Corrosive liquids -- are frequently used in the laboratory and have a high potential to cause external injury to the body.
- Corrosive solids -- cause delayed injury. Because corrosive solids dissolve rapidly in moisture on the skin and in the respiratory system, the effects of corrosive solids depend largely on the duration of contact.
- Examples of commonly-used corrosives:
- sulfuric acid
- hydrochloric acid
- nitric acid
- ammonium hydroxide
- sodium hydroxide
Oxidizers:
- An oxidizing agent is a chemical used to provide oxygen for chemical reactions. Oxidizers spontaneously evolve oxygen at room or slightly elevated temperatures, and can explode violently when shocked or heated. Because they possess varying degrees of chemical instability, oxidizing agents are explosively unpredictable and, therefore, represent a particularly hazardous safety threat.
- Examples of oxidizing agents:
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| Reactivity |
Explosive Materials:
- Explosive materials are chemicals that cause a sudden, almost instantaneous release of large or small amounts of pressure, gas, and heat when subjected to sudden shock, pressure, or high temperature.
- Examples of commonly-used explosive chemicals:
- acetylene
- hydrogen
- nitrogen containing compounds
- ammonia
- halogens
- perchlorates
- Metals of group IA react with water to release hydrogen gas and heat which is an explosive combination.
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The newest labels on chemical bottles are related to the NFPA diamond.
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ANSI and OSHA use the following signs related to safety:
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 Major safety hazard
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 A hazard to safety
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 Possible hazard
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 Safety information
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A few other signs related to safety:
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The Department Of Transportation (DOT) has broad authority to regulate hazardous materials that are in transport, including the discretion to determine which materials shall be classified as "hazardous". These materials are placed in one of nine categories, based on their chemical and physical properties. Based on the classification of the material, the DOT is also responsible for determining the appropriate packaging materials for shipping or transport. Finally, also based on the material classification, strict guidelines are furnished for proper labeling/marking of packages of hazardous materials offered for transport, and for placarding of transport vehicles.
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Class 1: Explosives
- Division 1.1 Explosives with a mass explosion hazard
- Division 1.2 Explosives with a projection hazard
- Division 1.3 Explosives with predominantly a fire hazard
- Division 1.4 Explosives with no significant blast hazard
- Division 1.5 Very insensitive explosives
- Division 1.6 Extremely insensitive explosive articles
This placard is required when transporting any quantity of Class 1.1, 1.2, or 1.3 explosive,
or over 1001 lbs of Class 1.4 or 1.5
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Class 2: Gases
- Division 2.1 Flammable gases
- Division 2.2 Nonflammable gases
- Division 2.3 Poison gas
- Division 2.4 Corrosive gases
This placard is required when transporting over 1001 lbs of Class 2.1 or 2.2, or when transporting any quantity of poisonous (Class 2.3) gas.
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Class 3: Flammable liquids
- Division 3.1 Flashpoint below -18 oC (0 oF)
- Division 3.2 Flashpoint -18 oC and above, but less than 23 oC (73 oF)
- Division 3.3 Flashpoint 23 oC and up to 61 oC (141 oF)
This placard is required when transporting over 1001 lbs of flammable materials.
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Class 4: Flammable solids; spontaneously combustible materials; and materials that are dangerous when wet
- Division 4.1 Flammable solids
- Division 4.2 Spontaneously combustible materials
- Division 4.3 Materials that are dangerous when wet
These placards are required when transporting over 1001 lbs of Class 4.1 or 4.2 materials, or when transporting any quantity of a water reactive material (Class 4.3).
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Class 5: Oxidizers and organic peroxides
- Division 5.1 Oxidizers
- Division 5.2 Organic peroxides
Placards are required when transporting over 1001 lbs of oxidizers or organic peroxides.
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Class 6: Poisons and etiologic materials
- Division 6.1 Poisonous materials
- Division 6.2 Etiologic (infectious) materials
Placards are required when transporting any quantity of Class 6 material, and when transporting over 1001 lbs of a Class 6.1 material.
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Class 7: Radioactive materials
Any material, or combination of materials, that spontaneously gives off ionizing radiation. It has a specific activity greater than 0.002 microcuries per gram.
Placards are required on ANY quantity of radioactive material rated as III; it is not required on materials rated as I or II.
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Class 8: Corrosives
A material, liquid or solid, that causes visible destruction or irreversible alteration to human skin or a liquid that has a severe corrosion rate on steel or aluminum.
Placarding is required whenever the quantity exceeds 1001 lbs of a corrosive liquid.
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Class 9: Miscellaneous
A material which presents a hazard during transport, but which is not included in any other hazard class (such as a hazardous substance or a hazardous waste).
Placarding is not required for materials that are not classified. However, you may placard a material that presents a hazard during transport and weighs more than 1001 lbs.
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Research Links:
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