Document 00V60ReRk7zYxZkJDgNy6Z8M

VRD 0002025904 Chemical ToxHcHty & First Aid VRD 0002025205 Extremely Toxic Highly Toxic Moderately Toxic SIightly Toxic Very Low Toxicity Extremely Toxic Highly Toxic Moderately Toxic SIightly Toxic Very Low Toxicity Extremely Toxic Highly, Toxic Moderately Toxic SIightly Toxic Very Low Toxicity HASKELL Acute Oral LD 50 (rats) (mg/Vg) <5 5-50 50-500 500-5000 > 5000 Acute Vapor Inhalation, Not for Dusts or Aerosols 4-hour LC50 (rats) Atmospheric Concentration* PPTM mg/1 <10 < 0.08 10-100 100-1000 1000-5000 >5000 0.08-0.8 0.8-0.0 8.0-40 >40 Acute Skin Absorption LD50 {rabbits) {mg/kg) < 10 10-200 200-5000 5000-10,000 >10,000 Aquatic Toxicity 96-hour LC50 (mg/1) Extremely Toxic Highly Toxic Moderately Toxic Slightly Toxic Low Toxicity Very Low Toxicity < *Oa$ed on a chemical wi < 0.5 0.5-1 1-50 50-500 500-5000 > 5000 molecular weight of 200. ITY CLASSIFICATIONS Examples Probable Lethal Dose For 70 kg Han (150 lb) Sodium cyanide, parathion Acrolein, propionitri1e and Cl ass B Poisons DDT Aspirin, sodium chloride Sugar A taste (less than 7 drops) Between 7 drops and 1 teaspoonful Between 1 teaspoon and 1 ounce Between 1 ounce and 1 pint (or 1 1b) More than 1 pint (1 lb) Perfluorofsobutylene (PFJB), acrolein Nitrogen dioxide HF, chlorine, sulfur dioxide CO Freon 12 (Dichiorodif1uoromethane) Tetraethyl pyrophosphate Acrylonitrile, Class B Poisons Sodium laurylsulfate Dimethyl formamide Isopropyl alcohol, ethylene glycol, trichlorethylene, acetone A few drops Between a few drops and 1 ounce Between 1 ounce and 1 pint (or 1 lb) Between 1 pint and 1 quart (or 2 lb) More than 1 quart (2 lb) Pentachlorophenol, DDT Chiordane Phenol, formaldehyde, benzene Sodium hydroxide, .acetic acid Adiponitrile Ethyl alcohol STATES OF MATTER One reason for focusing on states of matter in this presentation is that it provides a convenient way of presenting problems of containment of chemical substances and of explaining ways in which chemicals can be transported from one place to another. Another reason is. that the concept helps draw attention to various routes of exposure. A consideration of states of matter should help locate the source of a hazard. Solids can be found in containers such as drums or bags but may also sometimes be found on floors or bench tops, even though they shouldn't be there. Liquids are also confined to their containers, which may be cans or bottles; but they also can get loose. Gases are supposed to be in gas cylinders, but when they get out. they dif fuse to fill the available space. The further possibility of a change of state may result in a far wider dispersion of a chemical and a correspondingly greater chance of exposure. Gases, of course, can be dispersed more easily than chemicals in the other states. They may penetrate ordinary clothing, and they may be adsorbed on various surfaces. It should be noted that the density of gases may cause them to collect in layers and to rise or settle. This may result in an increased fire or explosion hazard or in an increased danger of toxic exposure. Liquids can evaporate, and the vapors can then pose the same kinds of hazards as gases. Liquids may also act as solvents both for gases and solids, and thus even if they are themselves inert, they may serve as a medium for carrying and dispersing hazardous materials. Solids can get into the air and be dispersed in the form of dust particles. Some substances can go directly from the solid to the gaseous state (sublime) and so pose the same hazards as gases. 9 H S IH B B B flMA A ROUTES OF ENTRY Industrial hygiene studies have been concentrated on a number of obvious danger points through which chemicals can come in contact with the body. The first point of contact is usually the skin, by direct contact. Because of their particular sensitivity and importance, the eyes are often given special attention. Chemicals can also get into the body by being swallowed. Normally this could only happen by accident in the chemical workplace, and it is something of a strain to imagine how such an accident could happen. It should be fairly obvious that a chemical process area is entirely unsuited for use as a lunch room, but you may feel that it is necessary to point this out. Finally, gases can be particularly dangerous because they will be breathed in. This consideration of routes of entry leads in turn to a consideration of the kind of protective gear required. The completeness of protection required depends on the severity of the hazard that may be encountered. Protective clothing, goggles, gloves, face masks, and respirators are all possibilities. The particular hazard in your plant should be evaluated, and the appropriate response made. The right protective equipment must be picked for the job. Some solvents will go right through shoe leather and on through the skin of the foot. Obviously, workers must be trained in the location, use, and maintenance of protective equipment. Cleaning and disposal of contaminated equipment should also be provided for; it is not rational or safe to wear a source of contamination. SIGNS AND SYMPTOMS OF EXPOSURE The body will probably react to exposure to harmful chemicals. Itching, smarting or stinging sensations, reddening of the skin or a skin rash, eye irritation or reddening, choking or difficulty in breathing may result from exposure to hazardous chemicals. Inhalation of hazardous chemicals can result in nausea or dizziness. Some chemicals will have an anesthetic effect and will cause drowsiness or unconsciousness. Individuals may vary widely in their sensitivity to chemical exposure so, even if other workers seem to be unaffected, it is no proof that a worker complaining is "goldbricking". The body's own senses are extremely sensitive detectors. The OSHA standard recognizes this in requiring familiarization with the appearance and odor of chemicals used in a particular work area. Note that some chemicals can cause harm without being noticed. Hydrofluoric acid, for instance, can penetrate the skin and cause extensive damage without causing pain. Clearly, it is necessary to know about this kind of behavior ahead of time and to take ex tra precautions in such cases. VRD 000 2025967 A VfiD 0022025908 MATERIAL SAFETY DATA SHEETS The OSHA standard requires that chemical manufacturers and importers obtain or develop Material Safety Data Sheets for each hazardous chemical they produce or import. The information contained on the MSDS shall include at least the following: The identity used on the label; Physical and chemical characteristics, e.g., vapor pressure, flash point; Physical hazards, e.g., potential for fire or explosion, reactivity; Health hazards, including signs and symptoms of exposure and medical conditions aggravated by exposure to the chemical; Primary routes of entry to the body; Required or recommended exposure limits or threshold limit values; Recognition as a potential carcinogen; Required or recommended procedures for handling, use. protective measures during repair, and clean-up procedures; Appropriate engineering controls, work practices, or personal protective equipment; Emergency and first aid procedures; Date of preparation of the MSDS and of changes to it; The name, address, and telephone number of a responsible person who can provide further information on the hazardous chemical and emergency procedures, if necessary. MEASURING AND MONITORING An essential component of a plant safety program is the monitoring of the plant environment. An explanation of the need for and the importance of the monitoring program will do much to allay the worker's apprehensions. Mysterious black boxes are likely to rouse anyone's suspicions. Process control equipment (temperature and pres sure gauges, pH meters, for example) should be easy to explain. Sampling devices, whether batch or continuous, can also be pointed out. If it is appropriate, mention can be made of threshold limit values or peak concentration monitoring. It is natural enough for a worker to regard a personally worn monitor as a nuisance. Emphasize that personal monitoring equipment has a serious purpose and is used to protect the worker's health. This is an opportunity for you to provide instruction in the use, proper care, and maintenance of personal monitoring equipment in your plant. HEALTH HAZARDS Some of the hazards considered by the OSHA standard can be evaluated in terms of physical measurements. For instance, the Department of Transportation definition of a corrosive substance is based on the rate at which a steel plate it eaten away. However, even though it is less exact, the OSHA standard defines the hazards in terms of health ef fects. Corrosive hazards are evaluated in terms of results of skin testing on rabbits. The hazards specifically defined by the standard are: Carcinogens. These are substances that have been determined to cause cancer or to potentially cause cancer. Carcinogens or potential carcinogens are identified by the United Nations International Agency for Research on Cancer and the U.S. National Toxicology Program and may be already regulated as such by OSHA. Corrosives. These substances are defined in terms of a rabbit skin test. Label and MSDS information is important, because the chemical name may mislead an untrained worker. For example, many acids are corrosive, but not a// acids are corrosive. And not all corrosives are acids. Highly toxic. These substances are extremely poisonous in extremely small doses (defined in terms of animal tests). The normal danger is from ingestion, but dermal or inhalation toxicity is also a possibility. Irritants. These substances cause inflammation of the skin or eyes. The effects are evaluated in terms of rabbit skin or eye tests; Sensitizers. These substances cause a substantial proportion of exposed people to develop an allergic reaction. Toxic. These substances are distinguished from the "highly toxic" category be cause a larger dose is required to cause an effect. Target organ effects. The standard gives examples of chemicals that selectively damage the liver (carbon tetrachloride, for example), kidneys (halogenated hydro carbons), nervous system (carbon disulfide), blood or blood-forming organs (cyan ides), lungs (asbestos), reproductive system (dibromochloropropane), skin (ke tones), or eyes (acids). VRD 0002025909 A VRD 0002025910 DEFINITION OF CARCINOGENS Carcinogens are substances that cause cancer. Harmful health effects of chemicals can range from gross, destruction of tissue (as with corrosives) to interference with normal body functioning (as with toxic materials) to disruption of processes within body cells that affect their ability to divide. In cancer, modified body cells start reproducing and continue to do so out of control. This leads to tumor formation and is a severe assault on the body's normal functioning. Cancer is not a single disease. Many types of body cells can show cancerous activity and result in different symptoms. The causes of cancer are not definitely known, although many of them are thought to be dietetic or environmental. Medical research is making continued progress in isolating the causes. Methods of treatment are also improving and showing a higher rate of success. It has long been known that exposure to some substances is correlated with the development of cancer. With regard to dose levels and the duration of exposure, the range of effects seems to be broad. Some authorities hold that there is no safe exposure level, and this conservative view is certainly the safest one to take. From an occupational safety and health point of view the definition of a carcinogen results from its effects in animal testing. Specific exposure tests have been prescribed to be performed on test animals. The tests take about two years to run and analyze, so they are expensive and the amount of information obtained does not accumulate rapidly. There is an argument about the applicability of test data obtained with animals to humans. VXD 0002025^11 According to the OSHA standard, a chemical is considered to be a carcinogen if it has been; Evaluated by the International Agency for Research on Cancer and found to be a carcinogen or potential carcinogen; Listed in the Annual Report on Carcinogens published by the National Toxicology Program as a carcinogen or potential carcinogen. Regulated by OSHA as a carcinogen. OSHA specifically regulates the following 18 substances: 2-Acetylaminofluorene Acrylonitrile 4-Aminodiphenyl Arsenic, inorganic Benzidine bis-Chloromethyl ether Coke oven emissions 1,2-Dibromo-3-chloropropane 3,3'-Dichlorobenzidine 4-0imethylaminoazobenzene Ethyleneimine Methyl chloromethyl ether alpha-Naphthylamine beta-Naphthylamine 4-Nitrobiphenyl N-Nitrosodimethylamine beta-Propiolactone Vinyl chloride. It is important to keep the problem of carcinogens in the proper perspective. Millions of chemicals are known. Of these, perhaps 40,000 find some use in the chemical industry and commerce. Any given plant is not likely to use more than 2,000 at the most. Yet OSHA only specifically regulates 18 compounds. According to the OSHA standard, information on whether a compound is a carcino gen or not must be included on a safety label and a Material Safety Data Sheet for the substance. HEALTH HAZARDS POSED BY CARCINOGENS The problem of cancer initiation is extremely complex. Not only are the causes uncertain and possibly a combination of factors, including individual susceptibility; but the effects are not immediate. Some cancers may not become active for twenty years, so it is very difficult to trace back from the effect to the cause. Further complications arise because of the existence of promoters, substances which are not themselves carcinogenic but which can ultimately allow other substances to have a carcinogenic effect. DEFINITION OF CORROSIVES Corrosives are chemical substances that react with sufficient vigor to destroy the structural integrity of other materials. Some of them can eat away metals, and others can cause severe injury to living tissue resulting in the killing of body cells. From an occupational safety and health point of view the definition of a corrosive results from its effects on living tissue rather than on metal plates. Specific tests have been prescribed to be performed on test animals (usually rabbits), and corrosives are compounds that cause, in the words of the OSHA standard, "visible destruction of, or irreversible alterations in, living tissue by chemical action at the site of contact" during a four-hour test period. Corrosives are thus defined in terms of their chemical and physiological action, which does not have any particular relation to the chemical structural class. In other words, the name or structure alone is insufficient to identify a substance as a corrosive. For example, strong acids are corrosives (in its use here, "strong" is a technical term meaning highly ionized), but that is not to say that all acids are corrosives. Boric acid, for instance, is used as an eyewash. Information on whether a compound is a corrosive or not must ultimately be based on experimentation and will be recorded on a safety label and a Material Safety Data Sheet for the substance. u t s u i m an a A U iS lH B B Q AHA HEALTH HAZARDS POSED BY CORROSIVES The degree of danger posed by a compound depends on its reactivity. The amount of damage that can result depends on this reactivity, the concentration of the chemical, and the duration of exposure. Some substances are extremely dangerous; they will cause skin destruction in the animal test in less than three minutes exposure. Other substances have a slower corrosive action (resulting in skin destruction in from three to 60 minutes) but are regarded as particularly dangerous because the vapor is toxic. Some chemicals in this worst group are; Ally! chlorocarbonate Bromine Chromium oxychloride Chromosulfuric acid Fluorosulfonic acid Hydrofluoric acid Hydrofluoric acid Nitrating acid, mixtures Nitric acid Nitrohydrochloric acid Selenic acid Selenium oxychloride Sulfur trioxide Sulfur chlorides Sulfuryl chloride Thionyl chloride Trifluoroacetic acid Vanadium tetrachloride. Substances are regarded as presenting a medium danger if they can cause skin destruction in from three minutes to 60 minutes under test conditions but have no particular additional hazard. Some of these chemicals are: Acetic anhydride Acetic acid (50% to 80% concentration) Acetic acid, glacial Acetyl bromide Acetyl iodide Acetyl bromide Acetyl iodide Acrylic acid Alkyl, aryl or toluene sulfonic acid Ethyl chlorthioformate Ethylphenyldichlorosilane Ethylsuifuric acid Fluoroboric acid Fluorosilicic acid Formic acid Fumaryl chloride Hexafluorophosphoric acid Hexyl trichlorosilane Alkylamines Ally! trichlorosilane Aluminum chloride Aluminum bromide Ammonium hydrogen sulfate Ammonium hydrogen sulfate Ammonium polysulfide Ammonium hydrogen fluoride Ammonium sulftde Anisoyl chloride Antimony pentachloride Benzotrichloride Benzoyl chloride Benzyl bromide Boron trifluoride diethyl etherate Boron trifluoride dihydrate Boron trifluoride propionic acid complex Boron trifluoride acetic acid complex Bromoacetyl bromide Butyl trichlorosilane Caustic alkali liquids, not otherwise specified Cesium hydroxide Chloroacetic acid Chloroacetyl chloride Chromic acid Chromic fluoride 1,5.9-Cyclododecanetriene Cyclohexenyltrichlorosilane Di-n-butylamine Dibenzyldichlorosilane Dichloroacetic acid Dichloroacetyl chloride Dichlorophenyl trichlorosilane Hydrazine hydrate (not more than 64% by weight) Hydriodic acid Hydrobromic acid Hydrochloric acid Iodine monochloride Lithium hydroxide Nitrosylsulfuric acid Nonyl trichlorosilane Octadecyl trichlorosilane Octyl trichlorosilane 1-Pentol Phenyacetyf chloride Phenyl trichlorosilane Phenyl phosphorus thiodichloride Phenyl phosphorus dichloride Phosphorus tribromide Phosphorus trichloride Phosphorus oxychloride Phosphorus pentachloride Phosphorus pentabromide Phosphorus oxybromide Potassium bifluoride Potassium oxide Potassium hydrogen sulfate Potassium hydroxide Propyl trichlorosilane Pyrosulfuryl chloride Rubidium hydroxide Silicon tetrachloride Sodium hydroxide Sodium monoxide Sodium hydrogen fluoride Sodium sulfide Stannic chloride, anhydrous VRD 0002 02 59-1 4- N.N-Oiethyethyleno diamine Diethyldichlorosilane Diethylenetriamine Diethylthiophosphoryl chloride N,N-Dimethylcarbamoyl chloride N,N-Dimethylcyclohexylamine Diphenyldichlorosilane Diphenylmethyl bromide Dodecy! trichlorosilane Sulfuric acid Thiophosphocyl chloride Titanium trichloride Trichloroacetic acid Trichloroacetyl chloride Triethylenetetramine Trimethylacetyl chloride Valeryl chlorides Vanadium oxytrichloride Substances regarded as presenting a minor degree of danger (but still meeting the definition of skin destruction in a four-hour test) include: N-Aminoethylpiperazine Ammonia solutions (from 10 to 35% ammonia) Amyl acid phosphate Benzene sulfonyl chloride Butyl acid phosphate Butyric acid Chloropropionic acid Crotonic acid Cyanuric chloride Dicyclohexylamine 3-(Diethylamino)-propylamine Dimethylthiophosphoryl chloride Ethanolamine 2-Ethylhexylamine Hydroxylamine sulfate 3.3'-lminobispropylamine 1 sophoronediamine Methacrylic acid Phosphoric acid Phosphorous acid Phosphorus trioxide Propionic anhydride Propionic acid T etraethylenepentamine Tributylamine Triethylenediamine Trimethylcyclohexylamine Vanadium trichloride Zirconium tetrachloride It should be noted that some materials can pose multiple threats. The possibility of inhalation toxicity has been mentioned, and some substances are not only corrosive but are readily absorbed through the skin and can cause further systemic damage or poisoning. Corrosives are obviously especially reactive chemicals, and sometimes they can react with other chemicals to result in a worsened hazard situation. Some sub stances can decompose at high temperatures to release toxic gases. Others can react with water or even moisture in the air to release harmful substances. Others can react with organic material to generate heat. Others are not only corrosives but also flammable liquids or oxidizing materials. Information on these added dangers should be obtainable from a Material Safety Data Sheet. n t iiiM 9 0 aaa A DEFINITION OF GASES A gas is a material in a state of matter that tends to till the space available to it. If it is confined in a container it will expand to fill the whole container, and if it is loose in the air it will diffuse to fill a confining space (a room or building). Gases can pose the physical hazards associated with material kept at high pressure or readily flammable. Some gases also pose a health hazard because of their carcinogenic, poisonous, or corrosive characteristics. It is convenient to treat gases as a single class of compounds from the point of view of their handling and use in a chemical plant. Gases can be liquefied by subjecting them to pressure or by lowering their tempera ture. The ease with which this can be done depends on the molecular weight and the chemical structure of the substance. Permanent gases are those that cannot be liquefied at ordinary temperatures (hydrogen, oxygen). Liquefied gases can become liquid under pressure at ordinary temperatures (methyl bromide). Some gases will dissolve under pressure in a solvent, usually absorbed on porous material (acetylene). Some gases can be liquified at extremely low temperatures (oxygen is liquid at atmospheric pressure at -183C or -297*F). The practical consequence of this is that different gases may be stored under a wide range of pressure conditions--from atmospheric pressure to perhaps five times atmospheric. Even higher pressures can occur at higher temperatures or under reaction conditions. VRD 00020 259-1 6 A VRD 08020 259 17 HEALTH HAZARDS POSED BY GASES The health hazards identified by the OSHA Hazard Communication Standard are: Carcinogens: Corrosive materials; Toxic materials; Irritants: Sensitizers: Substances affecting target organs. If a gaseous substance presents one of these health hazards, the OSHA standard requires that information about the hazard should be listed on a hazard label and also be available on a Material Safety Data Sheet (MSDS). The fact that a substance is in the gaseous state automatically increases the danger of exposure because of the possibility of inhalation and eye and skin exposure. The OSHA standard requires labeling of "highly toxic" and "toxic" substances as determined from animal testing. Some poisonous gases are: Ammonia, anhydrous Arsine Boron trifluoride Bromine chloride Carbon monoxide Carbonyl fluoride Carbonyl sulfide Chlorine Cyanogen Diborane Dichlorosilane Ethylene oxide Fluorine Germane Hydrogen chloride, anhydrous Hydrogen fluoride, anhydrous Hydrogen sulfide Methyl bromide Methyl chloride Nitric oxide Nitrosyl chloride Phosgene Phosphine Selenium hexafluoride Sulfur dioxide Some flammable gases, which may pose a threat of fire or explosion, are; Acetylene Butadiene Butane Ethylene Ethyl methyl ether Hydrogen sulfide Carbonyl sulfide Cyanogen Diborane Dimethyl ether Ethane Ethylamine Ethyl chloride Hydrogen Methane Phosphine Propane Silane Vinyl chloride Vinyl bromide Some corrosive gases are: Boron trichloride Bromine chloride Chlorine pentafluoride Hydrogen bromide, anhydrous Hydrogen chloride, anhydrous Nitrosyl chloride Many gases are heavier than air and thus tend to form layers at the lowest level they can reach. Concentrations at floor level or in equipment wells may reach unexpectedly high levels. Even inert or nontoxic gases can displace air and collect in concentrations high enough to be suffocating. , VRD QM1V159M A VRD 0002025919 DEFINITION OF EXPLOSIVES An explosive is a chemical substance that in itself can react to produce gas at a temperature and pressure and at such a speed as to damage the surroundings. The explosive reaction can be initiated by ignition or shock. The severity of the reaction depends on the particular material and the conditions present. A whole range of effects is possible, including: Mass explosion hazard, in which the whole mass of the explosive substance is affected practically instantaneously; Projection hazard, in which a propulsive jet is formed but not a mass explosion hazard; Fire hazard or minor blast hazard; Relative insensitivity to ignition or shock. Besides the hazard of explosive substances, there is the hazard of explosive conditions in the workplace. Concentrations of vapor from a flammable substance may build up to form a combustible or explosive atmosphere. There is a characteristic lower concentration limit that must be reached before the mixture becomes explosive. For instance, the following are some lower combustion limits for some substances in air (percent by volume): Acetone Benzene Carbon disulfide Diethyl ether 2.5 1.4 1.2 1.8 Ethyl alcohol Hydrogen Octane Propane 3.2 4.0 0.9 2.1 VRD 0002025920 Considering the whole air space available, these numbers may seem fairly high. However, an explosive atmosphere need only build up in the immediate vicinity of the source. If an explosion occurs, it will almost certainly start a fire in the main body of mate rial. which will spread and which will also disperse the material. Characteristically, there is an upper explosive concentration also, where the mixture becomes so fuel-rich that it will not ignite. This is not a significant consideration in a safety program. Although mixtures of gases and vapors with air are likely to pose the principal explosive hazard, explosive mixtures can also be formed with dust particles in the air. For instance, flour mills have a serious problem controlling airborne particles. Explosive hazards can also result from the use of chemical equipment. Pressure can build up in pumping operations or in distillation columns. Chemical processes can also result in explosions. Many reactions result in a release of heat, which in turn will accelerate the reaction, which eventually may proceed with explosive vigor. HEALTH HAZARDS POSED BY EXPLOSIVES The principal danger posed by explosives is the physical one of detonation. Some explosive compounds may have a subsidiary health risk. For instance, nitroglycerin and dinitrophenol are toxic. Substances that are toxic, irritants, or sensitizers must be so labeled under the provisions of the Occupational Safety and Health Hazard Communica tion Standard (effective November 1985). Hazard warning information must be contained on a label and on a Material Safety Data Sheet for the material. Because considerable physical disruption can be expected from an explosion, the possibility of the release of toxic materials present in the workplace should be consid ered. A VRD 000202 521 DEFINITION OF OXIDIZERS The common definition of oxidation is the reaction of a material with oxygen (actually more highly technical definitions are sometimes used, but they need not concern us here). The source of the oxygen can be the atmosphere, which contains about 20% oxygen. Common oxidation reactions using atmospheric oxygen are respiration (breath ing), combustion (burning), or slow oxidation processes like rusting. The rate at which these reactions proceed depends on the concentration of oxygen present, among other factors. The oxygen in air is diluted by inert nitrogen in a ratio of four to one. so that the rate of oxidation is much less than it would be with pure oxygen. Oxidizers are substances that can release oxygen when they react and thus provide a self-contained source of energy to fuel a reaction (again, in a broader technical sense oxidizers may contain no oxygen-chlorine is an example). This property is very important in promoting useful chemical reactions, but it can also be a source of hazard. Oxidizers are'very reactive compounds, and the kinds of reactions that can occur depend on the other reactants that they come into contact with and the reaction conditions. When combining with combustible materials, oxidizers will burn fiercely. In contact with other substances spontaneous combustion may occur; that is, a slow oxidation reaction will cause heat to build up and ultimately result in combustion. With other substances, explosive mixtures may form that may be sensitive to friction. And finally, with extremely reactive substances, oxidizers may cause immediate combustion or explosion. All of these reactions are likely to proceed with considerable vigor releasing heat and possibly toxic gases. Some common oxidizers are: Aluminum nitrate Ammonium dichromate Ammonium nitrate Chlorates Hydrogen peroxide Magnesium nitrate Potassium nitrate Potassium peroxide Potassium persulfate Bromine pentafluoride Calcium chlorate Calcium perchlorate Perchlorates Permanganates Potassium nitrate Sodium nitrate Sodium permanganate Sodium peroxide ORGANIC PEROXIDES A special class of oxidizers very useful for their chemical properties is organic peroxides. They, too, can react explosively when involved in a fire. The transportation hazard label will normally say '`Organic Peroxide." A few examples of organic peroxides are: Acetyl peroxide Benzoyl peroxide Bis-(1 -hydroxycyclohexyl) peroxide iso-Butyl methyl ketone peroxide tert-Butyl peroxyacetate Di-(tert-butyl peroxy) phthalate Peracetic acid Tetralin hydroperoxide. HEALTH HAZARDS POSED BY OXIDIZERS Oxidizers as a class are not defined as a health hazard. They are more of a safety hazard, and the dangers of fire and explosion either from the compound itself or on reaction with another material have been pointed out. The health hazards identified by the OSHA Hazard Communication Standard are: Carcinogens; Corrosive materials; Toxic materials; Irritants; Sensitizers; Substances affecting target organs. If a substance presents one of these health hazards, and many oxidizers do, information about the hazard should be contained on a health-hazard label and also be available on a Material Safety Data Sheet, according to the requirements of the OSHA standard. Apart from these possible dangers, unnecessary exposure to any chemical should be avoided. Oxidizers are highly reactive, sometimes react with moisture to release toxic materials, and can cause burns. VRD 000202592? A DEFINITION OF POISONS Poisons are substances that are liable to cause death or serious injury if they are swallowed, inhaled, or come in contact with the skin. Mechanisms by which poisons act may differ widely, but the level of action is usually physiological. The poison interferes with the proper functioning of the body, for instance by affecting oxygen distribution in the bloodstream or by blocking nerve impulses. From an occupational safety and health point of view the definition of a toxic substance results from its effects on test animals. The OSHA standard defines two categories of health hazard. These are: Highly toxic materials. A chemical falling within any of the following categories: a. A chemical that has a median lethal dose of 50 milligrams or less per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 grams each. b. A chemical that has a median lethal dose of 200 milligrams or less per kilogram of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours) with the bare skin of albino rabbits weighing between two and three kilograms each. c. A chemical that has a median lethal concentration in air of 200 parts per million by volume or less of gas or vapor, or 2 milligrams per liter or less of mist, fume, or dust, when administered by continuous inhalation for one hour (or less if death occurs within one hour) to albino rats weighing between 200 and 300 grams each. I M S i n m AHA A VRD 0002025 9-24- Toxic materials. A chemical falling within any of the following categories: a. A chemical that has a median lethal dose of more than 50 milligrams per kilogram but not more than 500 milligrams per kilogram of body weight when administered oraliy to albino rats weighing between 200 and 300 grams each. b. A chemical that has a median lethal dose of more than 200 milligrams per kilogram but not more than 1,000 milligrams per kilogram of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours), with the bare skin of albino rabbits weighing between two and three kilograms each. c. A chemical that has a median lethal concentration in air of more than 200 parts per million but not more than 2,000 parts per million by volume of gas or vapor, or more than 2 milligrams per liter but not more than 20 milligrams per liter of mist. fume, or dust, when administered by continuous inhalation for one hour (or less if death occurs within one hour) to albino rats weighing between 200 and 300 grams each. Other classes of substances that have a physiological action and are defined as health hazards by the OSHA standard are: Irritants. Chemicals that are not corrosive but cause a reversible inflammatory effect on living tissue by chemical action at the site of contact. Conditions for a rabbit skin test are specified in federal regulations. Eye irritants are also defined in terms of animal tests in federal regulations. Note that the definition of an irritant is different in the shipping regiations of the Department of Transportation; an irritant is defined as a substance that in contact with fire or air gives off dangerous or in tensely irritating fumes. Because this is a more severe hazard, care should be taken to distinguish between shipping labels and health-effects labels. Sensitizers. Chemicals that cause a substantial proportion of exposed people or animals to develop an allergic reaction in normal tissue after repeated exposure to the chemical. HEALTH HAZARDS POSED BY POISONS The degree of danger posed by a poison depends on its physiological action, its route of attack, and its reactivity. The amount of damage that can result depends on these factors, the concentration of the chemical, and the duration of exposure. A whole range of physiological effects is possible. Poisons can interfere with the oxygen-distribution system of the body, paralyze muscles, and affect nervous-system activity. It is more difficult to guard against poisons that can be inhaled in the vapor phase or be absorbed through the skin. If the main hazard is ingestion of the poison, it should be relatively easy to guard against. Poisons can act almost instantaneously; cyanides are an example. Other materials may take a period of hours or a day; acute arsenic poisoning is an example. In cases of chronic poisoning, repeated small doses over a long period of time can impair health and even be life-threatening; chronic lead poisoning is an example of this. The symptoms of poisoning also have a wide range-from convulsions or cessation of breaking to no noticeable symptoms. It is possible for a poison to enter the system with no noticeable effect and then to result in delayed symptoms some time later. Some toxic substances that are regarded as particularly dangerous because of their high toxicity or threat of exposure are: Acetone cyanohydrin Arsenic acid, liquid Barium cyanide Bromobenzyl cyanide Calcium cyanide Chloropicrin Cyanogen bromide sym-Dichlorodimethyl ether Dimethyl sulfate Epibromohydrin Fluoroacetic acid Hydrocyanic acid Iron pentacarbonyl Lead tetraethyl Mercuric potassium cyanide Nickel carbonyl Osmium tetroxide Phenyl mercaptan Potassium fluoroacetate Potassium cyanide Sodium cyanide Sodium fluoroacetate Other toxic substances posing an intermediate level of hazard are: Aldol Allyt isothiocyanate Aniline Benzidine Benzonitrile Bromoacetone Cacodylic acid Carbontetrachloride Chloral Chloroform Diethylsulfate Dinitrobenzenes Dinitrotoluenes Epichlorohydrin Ethyl bromide Ethylene dibromide Lead arsenates Mercuric chloride Nitroanilines Nitrobenzene Nitrotoluenes Phenol Potassium arsenate Toluidines S m y r n a oaa A Substances posing a relatively small hazard are: Acrylamide Ammonium fluoride Bromoform Dichlorobenzenes Dichloromethane Furfuryl alcohol Hexachlorobenzene Hexachlorophene Resorcinol Some toxic gases, which pose an inhalation hazard, are: Ammonia, anhydrous Arsine Boron trifluoride Bromine chloride Carbon monoxide Carbonyl fluoride Carbonyl sulfide Chlorine Cyanogen Diborane Dichlorosilane Ethylene oxide Fluorine Germane Hydrogen chloride, anhydrous Hydrogen fluoride, anhydrous Hydrogen sulfide Methyl bromide Methyl chloride Nitric oxide Nitrosyl chloride Phosgene Phosphine Selenium hexafluoride Sulfur dioxide Note that the OSHA standard is based only on toxicity data without regard to subsidiary factors such as volatility. Whether or not the compounds listed above would be classed as "highly toxic" or "toxic" would depend on the results of toxicity testing. The information should be given on a warning label and on a Material Safety Data Sheet (MSDS) for the substance. VRD 0002025926 A DEFINITION OF SOLVENTS No single chemical class can be defined as a solvent, but in looking at plant operations in the chemical industry it is natural to consider solvents as a group because of their common characteristics in handling, use, and storage. Solvents are used to dissolve other materials. Some of them are thus used as cleaning fluids or for degreasing and others are used for extracting soluble materials from raw materials. Solvents are also used in chemical processing, because more uniform and controlled behavior can be obtained with chemicals uniformly present in solution. A wide variety of solvents is used because favorable reaction conditions have to be tailored to the kind of dissolved substances and reaction conditions required. Water is a very common solvent and dissolves a wide range of substances, particularly inorganic salts. However, many specialized organic liquids are also used because they meet particular requirements better. Many solvents are flammable liquids, and they thus present more of a safety hazard than a health hazard. However, there can also be health effects of all kinds-sofvents may be toxic, corrosive, or irritant. Information on these hazards should be available on a safety label and a Material Safety Data Sheet for the substance. VRD 0 00 2 2 5 m0 A FLAMMABLE LIQUIDS The flammability of materials is measured by a flashpoint test. The flashpoint is the lowest temperature at which the vapor of a combustible liquid can be made to ignite. Therefore, the lower the flashpoint, the greater is the danger of combustion, The flashpoint measured depends on the configuration of the test apparatus. The most consistent results are obtained in a closed-cup method. The Department of Transporta tion classifies "flammable liquids" as those having a flashpoint below 100F (37.8C) and "combustible liquids" as those having a flashpoint between 100F and 200F (93.3C). A classification more closely reflecting the degree of personal hazard has been developed by a United Nations committee of experts. This classification divides substances into three flashpoint ranges. The low flashpoint group consists of substances having a flashpoint below -18C (0F) (closed cup method), which are regarded as presenting great danger. Following are some of these substances: Acetal Acetaldehyde Acetone Acrolein Ally! amine Allyl chloride Amyl nitrite isoButyraldehyde Carbon disulfide 2-Chloropropane 2-Chloropropene Cyclohexane Cyclohexene Cyclopentane Cyclopentene Diethoxymethane Diethyl ether Diethylamine Diisopropyl ether 1,1 -Dimethoxyethane Dimethyl sulfide 2.3-Dimethylbutane Dipropyl ether Ethyl propyl ether Ethyl mercaptan Ethylamine Furan isoHeptene Hex-1-ene Hexadiene Hexane Isoprene Methyl formate Methyl propyl ether Methylal 2-Methylfuran Methylpentanes Monopropylamine Pentenes iso Petroleum spirit Propionaldehyde Propylene oxide Tetrahydrofuran Vinylidene chloride VRD 000 20 2 5 m A The intermediate flashpoint group consists of materials having a flashpoint from -18C (0F) to 23C (73F),which are regarded as presenting medium danger. Following are some substances in this group: Acrylonitrile Alkylamines Allyl alcohol Allyl formate Allyl ethyl ether Allyl bromide Amyl acetates Amyl amine Benzene Benzotrifluoride 2-8romobutane Bromopropanes Butanedione Butyl methyl ether Butyl isocyanate Butyl acetates Butyraldehyde Chloromethyl ethyl ether Chloroprene Cycloheptane Cyclohexene Diallylether Diethyl ketone Diethyl sulfide Dioxane Dipropylamine Ethanol Ethyl methyf ketone Ethyl butyl ether Ethyl acetate Ethylbenzene Heptanes Methanol Methyl propyl ketone 1-Methylpiperidine Naphtha, petroleum Propanol Pyrrolidine Toluene Xylenes The high flashpoint group consists of substances having a flashpoint from 23C (73F) to 61 C (141F), which are regarded as presenting minor danger. Following are some substances in this group: Amyl acetates Amyl nitrate Amyl butyrates Anisole Bromobenzene Bromopropanes Butanol isoButyric acid Chlorobenzene Oibromobenzene Diethylbenzene Ethyl butyrate Ethyl amyl ketone Formalin Furfural Hydrazine Nitroethane 2,4-Pentanedione Turpentine (IMA A Substances having a flashpoint above 61C (141F) are not considered to present a fire hazard, according to this classification scheme. The flashpoint is not the sole measure of the degree of hazard. Substances with low boiling points will evaporate to form combustible atmospheres so that the hazard is enhanced. Substances with high viscosity do not flow easily, so the hazard is less. TOXIC AND CORROSIVE HAZARDS Some common toxic solvents or reactants are: Aniline Benzonitrile Carbon tetrachloride Chloroform Chloropicrin Dichlorobenzenes Dinitrobenzenes Dinitrotoluenes Epichlorohydrin Ethylene dibromide Hexachlorobenzene Nitroanilines Nitrobenzene Nitrotoluenes Tetrachloroethylene Toluidines Xylidines Some corrosive solvents or reagents are: Acetic anhydride Acetic acid (50% to 80% concentration) Acetic acid, glacial Acrylic acid Alkylamines Benzoyl chloride Benzyl bromide Di-n-butylamine Diethylenetriamine Ethanolamine 2-Ethylhexytamine 1-Pentol Tributylamine Again, warnings of these hazards should be available on safety labels and Material Safety Data Sheets. VRD 0002025930 A I t*Z 0 Z 0 0 AHA HEALTH HAZARDS POSED BY SOLVENTS Various solvents can present any of the heath hazards specifically identified in the OSHA standard-carcinogens, corrosives, highly toxic substances, irritants, sensitizers, toxic substances, and substances having target-organ effects. A substance posing one of these health hazards should have a health-hazard warning label, and information should also be available on a Material Safety Data Sheet. Solvents should be used with adequate ventilation, because almost all organic solvents if inhaled will have an anesthetic effect, leading to wooziness and sleepiness or unconsciousness. Prolonged exposure, which could occur if an unconscious person remained in an atmosphere polluted by solvent fumes, could lead to death. Skin exposure to solvents should be avoided as a matter of common sense. Solvents can remove protective oils in the skin, and some of them can even penetrate the skin. Many solvents can cause systemic or target-organ damage (particularly to the liver and blood-forming organs). Even if the substance is not corrosive or toxic, chemical exposure is to be avoided.