chemical safety

panjian1983

a english material about chemical safety.

panjian1983

Chemical Safety Guidelines
Always follow these guidelines when working with chemicals:
•        Assume that any unfamiliar chemical is hazardous.
•        Know all the hazards of the chemicals with which you work. For example, perchloric acid is a corrosive, an oxidizer, and a reactive. Benzene is an irritant that is also flammable, toxic, and carcinogenic.
•        Consider any mixture to be at least as hazardous as its most hazardous component.
•        Never use any substance that is not properly labeled.
•        Follow all chemical safety instructions precisely.
•        Minimize your exposure to any chemical, regardless of its hazard rating.
•        Use personal protective equipment, as appropriate.
•        Use common sense at all times.
The five prudent practices of chemical safety sum up these safety guidelines:
1.        Treat all chemicals as if they were hazardous.
2.        Minimize your exposure to any chemical.
3.        Avoid repeated exposure to any chemical.
4.        Never underestimate the potential hazard of any chemical or combination of chemicals.
5.        Assume that a mixture or reaction product is more hazardous than any component or reactant.
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Material Safety Data Sheets
Before using any chemical, read the container label and the appropriate Material Safety Data Sheets (MSDSs). Container labels and MSDSs are good sources of information for chemical safety. They provide the following information:
•        Hazardous ingredients
•        Exposure limits
•        Physical and chemical characteristics, including the following:   
- Boiling point
- Vapor pressure
•        Physical hazards, including the following:   
- Flammability
- Explosives
- Reactivity
•        Health hazards, including chemicals that are:   
- Toxic
- Carcinogens
- Irritants
•        First-aid procedures
•        Proper leak, spill, and disposal techniques
•        Proper storage and handling procedures
•        Other special provisions
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Safe Handling Guidelines
Employees should treat all chemicals and equipment with caution and respect.
When working with chemicals, remember to do the following:
•        Remove and use only the amount of chemicals needed for the immediate job at hand.
•        Properly seal, label, and store chemicals in appropriate containers. Keep the containers clearly marked and in a well-ventilated area.
•        Check stored chemicals for deterioration and broken containers.
•        Learn how to dispose of chemicals safely and legally. Follow Tarleton State University waste disposal requirements.
•        Clean up spills and leaks immediately.
•        Know what to do in an emergency.
Likewise, when working with chemicals, remember the following:
•        Do not store chemicals near heat or sunlight or near substances which might initiate a dangerous reaction.
•        Do not transport unprotected chemicals between the work area and other areas. Use a tray, rack, cart or rubber carrier. Always use a secondary container when transporting hazardous or highly odorous chemicals on an elevator.
•        Do not pour hazardous chemicals down the sink.
•        Do not put fellow workers or yourself in danger.
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Hygiene and Chemical Safety
Good personal hygiene will help minimize exposure to hazardous chemicals.
When working with chemicals, follow these guidelines:
•        Wash hands frequently and before leaving the laboratory. Also, wash hands before eating, drinking, smoking, or applying makeup.
•        Remove contaminated clothing immediately. Do not use the clothing again until it has been properly decontaminated.
•        Follow any special precautions for the chemicals in use.
In addition follow these special precautions:
•        Do not eat, drink, smoke, or apply makeup around chemicals.
•        Do not wear contact lenses near chemicals, especially corrosives or volatile solvents.
•        Do not keep food or food containers anywhere near chemicals.
•        Do not use laboratory equipment to serve or store food or drinks.
•        Do not sniff or taste chemicals.
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Hazard Communication Program
Tarleton State University has a written program (Tarleton State University Hazard Communication Program) that complies with OSHA standards and the Texas Hazard Communication Act for hazardous chemicals. This program is available from the Safety Office. It requires the following:
•        Employee training (including recognition of signs of exposure)
•        Labeling procedures
•        MSDSs for chemicals at each workplace
•        Instructions on how to read and interpret MSDSs
•        Chemical inventory reporting procedures
•        Recordkeeping requirements
•        Emergency response procedures
Refer to the Tarleton State University Hazard Communication Program and other sections in this manual for detailed information on these topics.
An integral part of hazard communication is hazard identification. Everyone who works with hazardous chemicals should know how to read and interpret hazard information. Signs, like the NFPA diamond, alert employees to the known hazards in a particular location.
The following is a detailed explanation of the NFPA hazard classification codes:
•        Health (Blue):   
4 Can cause death or major injury despite medical treatment
3 Can cause serious injury despite medical treatment
2 Can cause injury. Requires prompt medical treatment
1 Can cause irritation if not treated
0 No hazard
•        Flammability (Red):   
4 Very flammable gases or liquids
3 Can ignite at normal temperatures
2 Ignites with moderate heat
1 Ignites with considerable preheating
0 Will not burn
•        Reactivity (Yellow):   
4 Readily detonates or explodes
3 May detonate or explode with strong initiating force or heat under confinement
2 Normally unstable, but will not detonate
1 Normally stable. Unstable at high temperature and pressure.
0 Normally stable and not reactive with water.
•        Specific Hazard (White):   
• Oxidizer - OX
• Acid - ACID
• Alkali - ALK
• Corrosive - COR
• Use No Water - W
• Radioactive - 
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Corrosives
A corrosive chemical destroys or damages living tissue by direct contact. Some acids, bases, dehydrating agents, oxidizing agents, and organics are corrosives.
Examples of acidic corrosives include the following:
•        Hydrochloric acid
•        Sulfuric acid
Examples of alkaline corrosives include the following:
•        Sodium hydroxide (lye)
•        Potassium hydroxide
Examples of corrosive dehydration agents include the following:
•        Phosphorous pentoxide
•        Calcium oxide
Examples of corrosive oxidizing agents include the following:
•        Halogen gases
•        Perchloric acid
Examples of organic corrosives include the following:
•        Phenol
•        Acetic acid
NOTE:
Concentrated acids can cause painful burns that are often superficial. Inorganic hydroxides, however, can cause serious damage to skin tissues because a protective protein layer does not form. Even a dilute solution such as sodium or potassium hydroxide can saponify fat and attack skin. At first, skin contact with phenol may not be painful, but the exposed area may turn white due to the severe burn. Systemic poisoning may also result from dermal exposure.
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Safe Handling Guidelines for Corrosives
To ensure safe handling of corrosives, the following special handling procedures should be used:
•        Always store corrosives properly. Refer to the MSDSs and the Chemical Storage section of this manual for more information.
•        Always wear gloves and face and eye protection when working with corrosives. Wear other personal protective equipment, as appropriate.
•        To dilute acids, add the acid to the water, not the water to the acid.
•        Corrosives, especially inorganic bases (e.g., sodium hydroxide), may be very slippery; handle these chemicals with care and clean any spills, leaks, or dribbles immediately.
•        Use a chemical fume hood when handling fuming acids or volatile irritants (e.g., ammonium hydroxide).
•        A continuous flow eye wash station should be in every work area where corrosives are present. An emergency shower should also be within 100 feet of the area.
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Corrosive Example: Perchloric Acid
Perchloric acid is a corrosive oxidizer that can be dangerously reactive. At elevated temperatures it is a strong oxidizing agent and a strong dehydrating reagent. Perchloric acid reacts violently with organic materials. When combined with combustible material, heated perchloric acid may cause a fire or explosion. Cold perchloric acid at less than 70% concentration is not a very strong oxidizer, but its oxidizing strength increases significantly at concentrations higher than 70%. Anhydrous perchloric acid (>85%) is very unstable and can decompose spontaneously and violently.
If possible, purchase 60% perchloric acid instead of a more concentrated grade. Always wear gloves and goggles while using perchloric acid. Be thoroughly familiar with the special hazards associated with perchloric acid before using it.
Heated digestions with perchloric acid require a special fume hood with a wash-down system.

panjian1983

Flammables
A flammable chemical is any solid, liquid, vapor, or gas that ignites easily and burns rapidly in air. Consult the appropriate MSDSs before beginning work with flammables.
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Flashpoint, Boiling Point, Ignition Temperature, and Class
Flammable chemicals are classified according to flashpoint, boiling point, ignition temperature. Flashpoint (FP) is the lowest temperature at which a flammable liquid gives off sufficient vapor to ignite. Boiling point (BP) is the temperature at which the vapor pressure of a liquid vaporizes. Flammable liquids with low BPs generally present special fire hazards. The FPs and BPs of certain chemicals are closely linked to their ignition temperature-the lowest temperature at which a chemical will ignite and burn independently of its heat source.
The following table illustrates flammable class characteristics:  
CLASS        FLASHPOINT        BOILING POINT        EXAMPLES
1A        <73        <100        Ethyl ether
"Flammable" aerosols
1B        <73        <100        Acetone
Gassoline
Toluene
1C        <73        <100        Butyl alcohol
Methyl isobutyl ketoene
Turpentine
2        100 - 140        -        Cyclohexane
Kerosene
Mineral spirits
3A        140 - 199        -        Butyl cellosolve
3B        <200        -        Cellosolve
Ethylene glycol
Hexylene glycol
The following table provides examples of common flammables and their flashpoint and class.  
CHEMICAL        FLASHPOINT        CLASS
Acetone        0        1B
Benzene        12        1B
Butyl Acetate        >72        1C
Carbon Disulfide        -22        1B
Cyclohexane        -4        1B
Diethylene Glycol        225        3B
Diethyl ether        -49        1A
Ethanol        55        1B
Heptane        25        1B
Isopropyl Alcohol        53        1B
Methanol        52        1B
Pentane        <-40        1A
Toluene        40        1B
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Conditions for a Fire
Improper use of flammable liquids can cause a fire. The following conditions must exist for a fire to occur:
&#8226;        Flammable material must be present in sufficient concentration to support a fire (i.e., fuel).
&#8226;        Oxygen or another oxidizer must be present.
&#8226;        An ignition source must be present (i.e., heat, spark, etc.).
When working with flammables, always take care to minimize vapors which act as fuel.
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Safe Handling Guidelines for Flammables
Follow these guidelines when working with flammable chemicals:
&#8226;        Handle flammable chemicals in areas free from ignition sources.
&#8226;        Never heat flammable chemicals with an open flame. Use a water bath, oil bath, heating mantle, hot air bath, etc.
&#8226;        Use ground straps when transferring flammable chemicals between metal containers to avoid generating static sparks.
&#8226;        Use a fume hood when there is a possibility of dangerous vapors. (Ventilation will help reduce dangerous vapor concentrations.)
&#8226;        Restrict the amount of stored flammables, and minimize the amount of flammables present in a work area.
&#8226;        Remove from storage only the amount of chemical needed for a particular experiment or task.
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Solvents
Organic solvents are often the most hazardous chemicals in the work place. Solvents such as ether, alcohols, and toluene, for example, are highly volatile or flammable. Chlorinated solvents such as chloroform are nonflammable, but when exposed to heat or flame, may produce carbon monoxide, chlorine, phosgene, or other highly toxic gases.
Always use volatile and flammable solvents in an area with good ventilation or in a fumehood. Never use ether or other highly flammable solvents in a room with open flames or other ignition sources present.
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Solvent Exposure Hazards
Health hazards associated with solvents include exposure by the following routes:
&#8226;        Inhalation:
Inhalation of a solvent may cause bronchial irritation, dizziness, central nervous system depression, nausea, headache, coma, or death. Prolonged exposure to excessive concentrations of solvent vapors may cause liver or kidney damage. The consumption of alcoholic beverages can enhance these effects.
&#8226;        Skin Contact:
Skin contact with solvents may lead to defatting, drying, and skin irritation.
&#8226;        Ingestion:
Ingestion of a solvent may cause severe toxicological effects. Seek medical attention immediately.
The odor threshold for the following chemicals exceeds acceptable exposure limits. Therefore, if you can smell it, you may be overexposed---increase ventilation immediately.
&#8226;        Chloroform
&#8226;        Benzene
&#8226;        Carbon tetrachloride
&#8226;        Methylene chloride
NOTE:
Do not depend on your sense of smell alone to know when hazardous vapors are present. The odor of some chemicals is so strong that they can be detected at levels far below hazardous concentrations (e.g., xylene).
In addition, some solvents (e.g., benzene) are known or suspected carcinogens.
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Reducing Solvent Exposure
To decrease the effect of solvent exposure, substitute hazardous solvents with less toxic or hazardous solvents whenever possible. For example, use hexane instead of diethyl ether, benzene or a chlorinated solvent.
NOTE:
The best all-around solvent is water; use whenever possible.
The following table outlines possible solvent substitutions:  
INSTEAD OF USING        SUBSTITUTE
Benzene        Cyclohexane
Toluene
Xylene
Halogenated solvents        Nonhalogenated solvents
Aromatic hydrocarbon        Aliphatic hydrocarbon
Trichloroethylene        1,1,1-trichloroethane
Diethyl ether        Hexane
Petroleum ether
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Solvent Example: DMSO
Dimethyl sulfoxide is unique because it is a good solvent with many water-soluble as lipid-soluble solutes. Due to these properties, dimethyl sulfoxide is rapidly absorbed and distributed throughout the body. It can also facilitate absorption of other chemicals such as grease, oils, cosmetics, and other chemicals that may contact the skin.
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Toxic Chemicals
The toxicity of a chemical refers to its ability to damage an organ system (kidneys, liver), disrupt a biochemical process (e.g., the blood-forming process) or disturb an enzyme system at some site remote from the site of contact. Toxicity is a property of each chemical that is determined by molecular structure. Any substance can be harmful to living things. But, just as there are degrees of being harmful, there are also degrees of being safe. The biological effects (beneficial, indifferent or toxic) of all chemicals are dependent on a number of factors.
For every chemical, there are conditions in which it can cause harm and, conversely, for every chemical, there are conditions in which it does not. A complex relationship exists between a biologically active chemical and the effect it produces that involves consideration of dose (the amount of a substance to which one is exposed), time (how often, and for how long during a specific time, the exposure occurs), the route of exposure (inhalation, ingestion, absorption through skin or eyes), and many other factors such as gender, reproductive status, age, general health and nutrition, lifestyle factors, previous sensitization, genetic disposition, and exposure to other chemicals.
The most important factor is the dose-time relationship. The dose-time relationship forms the basis for distinguishing between two types of toxicity: acute toxicity and chronic toxicity. The acute toxicity of a chemical refers to its ability to inflict systemic damage as a result (in most cases) of a one-time exposure to relative large amounts of the chemical. In most cases, the exposure is sudden and results in an emergency situation.
Chronic toxicity refers to a chemical's ability to inflict systemic damage as a result of repeated exposures, over a prolonged time period, to relatively low levels of the chemical. Some chemicals are extremely toxic and are known primarily as acute toxins (hydrogen cyanide): some are known primarily as chronic toxins (lead). Other chemicals, such as some of the chlorinated solvents, can cause either acute or chronic effects.
The toxic effects of chemicals can range from mild and reversible (e.g., a headache from a single episode of inhaling the vapors of petroleum naphtha that disappears when the victim gets fresh air) to serious and irreversible (liver or kidney damage from excessive exposures to chlorinated solvents). The toxic effects from chemical exposure depend on the severity of the exposures. Greater exposure and repeated exposure generally lead to more severe effects.
Exposure to toxic chemicals can occur by:
&#8226;        Inhalation
&#8226;        Dermal absorption
&#8226;        Ingestion
&#8226;        Injection
NOTE:
Inhalation and dermal absorption are the most common methods of chemical exposure in the workplace.
The following sections provide examples and safe handling guidelines for the following types of toxic chemicals:
&#8226;        Toxicants
&#8226;        Carcinogens
&#8226;        Reproductive Toxins
&#8226;        Sensitizers
&#8226;        Irritants
IMPORTANT:
Minimize your exposure to any toxic chemical.

slhy2002

too long!~~

qitaoanqua

Very important!

mtugtao

very useful material

martin吴晓

These is a good guideline for chemical safety magt details
i think better to have a general follow chart about chemical safety magt. , from purchase application to chemical waste treatment~

qitaoanqua

studying

cherryhengheng

thanks

xiakexing2012

thanking for you sharing

hartright

thanks        

sgdf

thanks for your sharing!