Plants, toxic hazards

Instrumentation (Arthur D. Little, Inc., and Levine, 1986.) Instrument systems are an essential part of the safe design and operation of systems for storing and handling highly toxic hazardous materials. They are key elements of systems to eliminate the threat of conditions that could result in loss of containment. They are also used for early detection of releases so that mitigating ac tion can be taken before these releases result in serious effects on people in the plant or in the public sector, or on the environment. 

Munition grade agents typically consist of at least one malodorant agent (10-90%) and an odor intensifier (0.5-5%) dissolved in a liquid carrier. Solvents include volatile hydrocarbons, plant/vegetable oils, and water. Solvents typically pose minimal toxic hazards themselves. Compositions are typically colorless to yellow liquids. As the agent ages and decomposes it may discolor and become brown. 

Chemical plants contain a large variety of hazards. First, there are the usual mechanical hazards that cause worker injuries from tripping, falling, or moving equipment. Second, there are chemical hazards. These include fire and explosion hazards, reactivity hazards, and toxic hazards. 

The chemical process industries employ many substances that contribute to air and water pollution, hazardous waste generation, soil contamination, fire and explosion risks, and the exposure of humans, animals and plants to hazardous and/or toxic substances. This article discusses which substances are hazardous and identifies the opportunities for replacing these substances with less-hazardous substitutes. 

Transportation of raw materials to depots and plants, by oil tankers, natural gas pipelines, barges, trains, and trucks, can create hazards. Another set of transportation hazards is posed by chemical intermediates (produced in one plant and transported to another plant for further processing) and industrial wastes. Sometimes, they travel past crowded urban areas, pristine beaches, and harbor tunnels. The hazards of oil spills on beaches by tankers are well known, and so are the instances of ruptures and breaks in oil and natural gas pipelines, which produce fire and pollution hazards. Trains and trucks can overturn in centers of habitation, and can lead to flames and explosions, as well as toxic hazards to the community. Toxic chemicals are barred from being trucked in tunnels under harbors and rivers. The storage of raw material and intermediates at plants or... 

Manufacturing of the products from the raw materials and intermediates is done in industrial plants, where flammability, explosion, and toxic hazards exist for the workers and their neighbors. Plant discharges into the air and of liquid and solid wastes on to the land and into the water pose another set of potential hazards. 

Plant Fireproofing. There is a growing practice in the chemical industry of locating principal equipment out of doors and to enclose only a control room where all instruments and control equipment are centered. The control room should be resistant to potential explosion, fire, and toxicity hazards of processes in the vicinity. Prompt and ordedy shutdown of processes following a serious incident is essential in order to minimize personnel-injury and property-loss hazards (65,66). 

The Dow Fire and Explosion Index (FEI) (12) and the Dow Chemical Exposure Index (CEI) (14) are two commonly used tools that measure inherent safety characteristics. Gowland (25) reports on the use of the FEI and CEI in the development of safety improvements for a urethane plant. Tables 1 and 2 illustrate the application of the FEI and CEI in measuring inherent safety characteristics of process design options. These indices measure the inherent safety characteristics of processes in only two specific areas—fire and explosion hazards and acute chemical inhalation toxicity hazards. Other indices would be required to evaluate other types of hazards. 

Two of the standards directly related to worker health and important in design work are Toxic Hazardous Substances and Occupational Noise Exposure. The first of these two concerns the normal release of toxic and carcinogenic substances, carried via vapors, fumes, dust fibers, or other media. Compliance with the Act requires the designer to make calculations of concentrations and exposure time of plant personnel to toxic substances during normal operation of a process or plant. These releases could emanate from various types of seals and from control-valve packings or other similar sources. Normally, the designer can meet the limits set for exposure to toxic substances by specifying special valves, seals, vapor-recovery systems, and appropriate ventilation systems. 

Piping systems may be relatively simple or complex and may convey utility services and chemical fluids that can be highly flammable, highly toxic, corrosive, erosive, or any combination of these properties. Piping systems within chemical plants handling hazardous Iluids must be designed, fabricated, tested, operated, and maintained consid-... 

The Plant Safety Officer identifies the toxic hazards of chemical species involved in a particular process. He also recommends what protective equipment may be required to preclude personal injury. 

Van Gils, G. J., and M. Prrbazari. 1985. Pilot plant investigations for the removal of toxic pollutants from industrial laundry wastewater. In Proceedings of the Mid-Atlantic Industrial Waste Conference on Toxic Hazardous Wastes, ed. I. J. Kugehnan, pp. 186-95. Lancaster, PA Technomic. 

Each selected commodity will be analysed, using the procedures developed for Hazard Analysis by Critical Control Points (HACCP), for each of the following seven aspects of safety and/or quality microbial toxins and abiotic contaminants correspondence with traditional values about proper food nutrient content and food additives harmful micro-organisms freshness and taste natural plant toxicants and adulterations. 

It is preferable to avoid toxic hazards, where practicable, by using materials which are of low toxicity. This will not always be possible, and plant operations can lead to toxicological problems in two main areas ... 

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