Explosive chemicals labelling

Explosive chemicals tend to be governed by separate legislation, e.g., in the UK, The Classification and Labelling of Explosives Regulations 1983. These require the HSE to classify any explosive before it may be supplied. Under the scheme, explosives are labelled according to a classification based on hazard division (Table 12.7), and on compatibility (Table 12.8), which takes into account their sensitivity, explosivity and chemical nature. Labels are diamond shaped the top half is reserved for the pictograph and division number, the bottom half shows the hazard code and the classification number. Figure 12.1 shows the label for Class 1, Division 1.1, 1.2 or 1.3 explosive. 

The American National Standards Institute (ANSI) has established a voluntary standard for chemical labeling, ANSI Z129.11994, Hazardous Industrial Chemical Precautionary Labeling, which includes readily identifiable symbols for poisons, corrosives, flammables, and explosives. Irritants, combustible liquids, pyrophoric chemicals, oxidizers, sensitizers, physiologically inert vapors, gases and other hazardous materials are also addressed. 

To avoid or minimise accidents in the chemical laboratory, such as fires and explosions, and to ensure that students and staff are not exposed to odier health hazards, they should be aware of the risks involved in handling chemicals and in carrying out reactions. In addition, they should know the measures required to deal widi hazardous situations. They should be familiar with the use and situation of fire extinguishers, protective blankets, eye wash facility, first aid box, as well as evacuation procedure in case of fire or explosion. Chemicals manufacturers are obliged by law to label all hazardous chemicals with a warning sign to indicate the type of hazard. When chemicals are dispensed in containers other than those supplied by manufacture, these containers should be also clearly labelled for the possible hazards. 

Some substances which may explode by impact when diy or in contact with combustible substances are labelled explosive and are supplied wet with water or a suitable solvent. These explosive chemicals should be stored away from combustible chemicals in safe storage metal cabinets and should never be allowed to become dry. Picric acid is an example. Its aqueous solution is sometimes used for treating bums. It is dangerous to allow students to experiment with explosive substances. 

Hypergolic A hypergolic mixture ignites upon contact of the components without any external source of ignition (heat or flame). The only field, in which this is a desirable event, is in rocket fuel research. Accidental mixing of incompatible materials can lead to a fire or explosion. Here is one example provided by the staff at ILPI of what can happen, when incompatibles are mixed. Always read the labels on your bottles (don t assume a chemical s identity by the shape, size, or color of the bottle), and know what materials are incompatible with the chemicals that you are using. 

Labour regulations have a code 19 with regards to the labelling of chemical compounds Can form explosive peroxides . Ethers with code 19 are listed in the table below ... 

Anon. Chemical Engineer, 1996, (620), 4 ibid, 1996, (621), 7 A tanker of aqueous sodium chlorite was part charged to a tank of epichlorohydrin before it was reported it was mis-labelled. There was a very violent subsequent explosion, which blew down the wall of an adjacent factory. (The editor suspects it was, in fact, sodium hypochlorite, commonly known simply as hypochlorite, which sounds like epichlorohydrin. Sodium hypochlorite would be expected to be the more reactive of the two, generating an alkyl hypochlorite.)... 

When the NFPA diamond is used for container or vessel labeling, and the white (bottom) quadrant contains the W symbol, the material will react violently or explosively with water, and a chemical reactivity hazard obviously exists. However, if the W symbol is not present, the material may still be water reactive, but at a slower rate, since the pur-pose of the NFPA symbol is to alert emergency responders to significant, immediate water reactivity n. hazards. Water reactivity is often very rapid, but can j also be slow. The reaction may generate sufficient gas Twy to rupture a closed container or vessel. The reaction of f an organic material with water may be delayed due to reaction only occurring at the interface. 

There are OSHA standards designed to protect employees from acute chemical hazards resulting lfom reactive incidents-including fires, explosions, and toxic releases. The Hazard Communication Standard (29 CFR 1910.1200) requires chemical manufacturers to evaluate chemicals produced or handled in their workplace and to communicate the hazards associated with the products they produce via labels and MSDSs. The standard also requires all employers to provide information to employees about the hazardous chemicals to which they could be exposed. The PSM Standard (29 CFR 1910.119) requires employers to prevent or minimize the consequences of catastrophic releases of highly hazardous chemicals, including highly reactive chemicals. 

A more extensively investigated precursor to chemically generated C atoms is diazotetrazole (6), which is easily prepared from readily available 5-aminotetrazole (7). " In this method, 7 is converted into the corresponding diazonium chloride 8, which is coated on the walls of a flask and pyrolysed in the presence of a gaseous substrate (Eq. 6). This technique has the drawback that 8 is extremely explosive and only small quantities can be prepared at a time. " However, the synthesis of 7 with a labeled carbon is quite simple, allowing convenient evaluation of the fate of the reacting carbon. " ... 

The first recorded dust explosion occurred when a bakery storeroom exploded in a small city called Turin (Italy) way back in 1785. Such an explosion is also labeled as thermobaric , a chemical reaction that produces extremely high pressure and heat very rapidly. In the early 1960s, scientists began experimenting with this concept to produce a weapon that uses the same principle, but employs volatile gases and finely powered explosives. 

Committee of Experts has been allocated a unique four-digit number, called the Substance UN Number (or simply the UN Number). Thus a hazardous substance can be distinctly identified by the Substance UN Number (also called the Substance Identification Number or SIN). UN Serial number 0001 to 1000 are reserved for Class 1 items, that is, explosives and ammunition. The nine classes of dangerous goods and hazardous chemicals with a distinctive diamond shaped label bearing a pictorial diagram for quick hazard recognition are ... 

Chemicals should be stored properly. For example, flammable chemicals (e.g ethanol, methanol, acetone, methyl ethyl ketone, petroleum distillates, toluene, benzene, and other materials labeled flammable) should be stored in approved flammable storage cabinets, and flammable chemicals requiring refrigeration should be stored in explosion-proof refrigerators. Oxidizers should be segregated from other chemicals, and corrosive acids (e.g., sulfuric, hydrochloric, nitric, perchloric, and hydrofluoric acids) should also be stored in a separate cabinet, well-removed from the flammable organics. 

Did you know that many of the chemical products in your home are hazardous, too For example, common household bleach, when used as directed, is safe for disinfecting and whitening clothing. Hazard labels on bleaching products, however, warn against mixing bleach with acids, household ammonia, or products that contain these chemicals. Bleach, when combined with acids, produces toxic chlorine gas. The products of combining bleach with ammonia are explosive. 

Today, almost everyone works or lives with chemicals and chemical prodncts. Over the centuries man has lived in a chemical age, but especially so during the past several decades. Many of the chemical substances can have deleterious effects on animals, humans, and the environment. These substances are capable of causing physical hazards (e.g., lire or explosion) or health hazards (such as systemic toxicity and chemical bums). Improper use of chemical substances causes a wide range of health hazards. It is the responsibility of the user to evaluate each chemical substance and know its potential to cause adverse health effects and pose physical hazards, such as flammability in the workplace. The manufacturers, importers, and distributors of different chemical substances must be sure that containers of hazardous chemicals leaving the workplace are properly labeled with the identity of the chemical and appropriate hazard warnings. In the workplace, each container must be marked with the identity of hazardous chemicals contained in it and must show hazard warnings appropriate for employee protection. 

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