Three Common Hazards

A common perception is that reactive incidents are primarily the result of runaway reactions. In fact, analysis of data from the 167 incidents suggests that other types of reactive hazards should also be of concern. CSB data analysis identified three common types of reactive hazards (see Appendix A for definitions) ... 

Table A-3. Some recommended simple physical and chemical diying methods for thirty-three common organic solvents -H- method gives superdry solvents with less than 1 ppm water -I- solvent sufficiently dry for most chemical applications (-I-) often used but less efficient — explosive hazard ( ) or other chemical reaction no entry means not recommended or no information in the literature. For extensive compilations of more sophisticated... 

Three common types of caught-in or -between hazards ... 

There are three common forms of conveyor - belt, roller and screw conveyors. The most common hazards and preventative measures are ... 

List the three common healthcare hazards listed in the chapter. 

There are three commonly used radioisotopes that pose definite hazards if improperly handled or have unique characteristics or hazards associated with their use. This section contains detailed procedures and precautions for the use of tritium, and radioiodine ( I and... 

The potential for pipeline failure caused either directly or indirectly by corrosion is probably the most common hazard associated with steel pipelines. The corrosion index was organized in three categories to reflect three types of environment to which pipelines are exposed, i.e., atmospheric corrosion, soil corrosion, and internal corrosion. Table 4.3 contains the elements contributing to each type of environment and the suggested weighting factors. 

In this section we give a brief description of three commonly used methods of safety analysis Fault Tree Analysis, Event Tree Analysis and Failure Mode and Effect Analysis. Those are the methods which, in our opinion, can mostly benefit fix)m being extended with more formal semantics. We do not cover here Hazard and Operability Study (HAZOP) which is a "structured brainstorm" - type method with the main stress on managerial aspects. However, as HAZOP may make use of FTA, ETA and/or FMEA, it can also benefit firom the proposed approach. 

The aromatic hydrocarbons are used mainly as solvents and as feedstock chemicals for chemical processes that produce other valuable chemicals. With regard to cyclical hydrocarbons, the aromatic hydrocarbons are the only compounds discussed. These compounds all have the six-carbon benzene ring as a base, but there are also three-, four-, five-, and seven-carbon rings. These materials will be considered as we examine their occurrence as hazardous materials. After the alkanes, the aromatics are the next most common chemicals shipped and used in commerce. The short-chain olefins (alkenes) such as ethylene and propylene may be shipped in larger quantities because of their use as monomers, but for sheer numbers of different compounds, the aromatics will surpass even the alkanes in number, although not in volume. 

Individual Risk expresses the risk to a person exposed to a hazard. It is normally calculated as the frequency of serious or fatal injuries per year (fatalities/year). Three of the more common individual risk measurements are ... 

Our group of neighbors together told us three typical stories to explain their use of lawn chemicals despite knowledge of their hazards. The first of these-centeiing on trust in professional experts-was most common, since several residents employed other people to manage their lawns. Generally, residents believed that because lawn chemical producers and the companies that apply... 

Arsenic. As, at wt 74.91 exists in three modifications all corresponding to the formula As4i mw 299.64. The most common form is the crystalline or a-form, known also as metallic arsenic. Its mp is 814° at 36 atm press, sublimation point 615, d 5 = 72 at RT (5.6-5.9 for commercial grade) and hardness 3.5 Mohs. Prepn props are given in Refs 1-6 toxicity, fire expln hazards of As dust are discussed in Ref 7. Arsenic is used in some alloys and for hardening lead shot... 

A proposal for assessment criteria on a four levels scale is presented in Table 3.1. This four levels scale for the severity is commonly used in the fine chemicals industry [4] and has its roots in the Zurich Hazard Analysis (ZHA) developed by the Zurich Insurance Company [5]. If the assessment is performed on a three levels scale, the upper levels critical and catastrophic may be merged into one level, high. ... 

The Mitre Model and site ranking. EPA has developed a hazard assessment model (commonly called the Mitre Model) to help rank problem hazardous waste sites for potential Superfund response. The model is a relatively simple one, with minimal data requirements. The model is designed to provide scores for actual or potential impacts on health or the environment by three routes of exposure — groundwater, surface water, or air emissions — as well as by direct contact or fire and explosion. Parameters include toxicity, quantity, physical state and persistence of the waste at a site characteristics of a potential route (to groundwater, surface water, or air) of release of the wastes, e.g., soil permeability the mode of exposure or use of the natural resource, e.g., an aquifer or surface waters used for drinking water and the target of... 

Overall, the major premise for our approach is a directional orientation toward risk reduction. The evaluation procedure used follows a four-step process which considers first Hazard Identification second, Hazard Evaluation third, Risk Evaluation and fourth, Risk Response. To avoid any misunderstanding of terms, the combined activities of the first three steps can be considered as what is commonly referred to as making a "Risk Assessment." The fourth step, Risk Response, necessarily must follow when the process is used to make practical decisions. 

When a patient presents to the ED, the nurse must ascertain that an exposure has taken place. Nurses should suspect chemical exposures for any mass casualty incident in which multiple ill persons with similar clinical complaints (point-source exposure) seek treatment at about the same time or in persons who are exposed to common ventilation systems or unusual patterns of death or illness. The ED may or may not receive notification in advance that a chemical explosion or leak has occurred. In either case, ED health care providers have the following three primary goals in treating a patient who has been exposed to a hazardous material and may be contaminated or who has not undergone adequate decontamination before arrival at the hospital ... 

Solvents may be classified according to their polarity into three groups apolar aprotic solvents, dipolar aprotic solvents, and (polar) protic solvents. Examples of these three classifications for some common laboratory solvents are listed in Table 16.1, in order of increasing polarity (indicated by dielectric constant), together with some other solvent properties. For information on the hazards and toxicity of solvents, see Chapter 11. 

---