Hazardous chemical

FIGURE 23.6 Hazardous chemicals can be found on most worksites. 

A more significant issue is that regarding mixtures. The information does not exist to show the risk of illnesses, long-term illnesses, or the toxicity of combining these hazardous chemicals. At present, it is assumed that the most dangerous chemical of the mixture has the most potential to cause serious health-related problems, then the next most hazardous, and so on. However, little consideration is given 

Actually, the amount of information that exists on dose/response for chemicals and chemical mixtures is limited. This is especially true for long-range or latency effects. If a chemical kills or makes a person sick within minutes or hours, the dose/response is easily understood. However, if chemical exposure over a long period of time results in an individual s death or illness, then the dose needed to do this is, at best, a guess. It most certainly does not take into account other chemicals the worker was exposed to during his or her work life and whether they exacerbated the effects or played no role in the individual s death or illness. This is why it is critical for individual workers to keep their exposure to chemicals as low as possible. Even then, there are no guarantees that they may not come down with an occupational disease related to chemical exposure. 

With this point made, it becomes critical that employers know the dangers of the chemicals being used present to their workforce. Employers need to obtain and review the MSDSs for all chemicals in use on their worksite and take the proper precautions recommended by those MSDSs. Also, it behooves workers to get copies of and review the MSDSs for chemicals that they use. 

Many employers and workers as well as physicians are not quick or trained to identify the symptoms of occupational exposure to chemicals. In one case, two men painted for eight horns with a paint containing 2-Nitropropane in an enclosed environment. At the end of their shift one of the workers felt ill and stopped at the emergency center at the hospital. After examination, he was told to go home and rest 

At that time, chemical controls focused on imports and exports of chemicals and on the management of certain hazardous chemicals. 

State Council Decree 591, Regulations on the Safe Management of Hazardous Chemicals (originally published in 2002 and amended in 2011), provides another form of chemical control in the People s Republic of China [130,131]. As the name indicates, these regulations apply only to designated hazardous chemicals, which are defined as chemicals that are toxic, corrosive, explosive, flammable, or combustion-supporting and can do harm to people, facilities, or the environment. Importers and manufacturers must register their hazardous chemicals, and manufacturers and vendors have to obtain licenses 

Product Stewardship Life Cycle Analysis and the Environment 

The Catalog of Hazardous Chemicals, per updates proposed in late 2013 and pending as of late 2014, contains approximately 3,000 chemicals [133,134] including  

5 Five-Year Plan Concerning Prevention and Control of Chemical Environmental Risks 

Human activities are associated with the use and disposal of a variety of chemicals and chemical products. This is the situation for a householder, a laboratory student, and also the industry worker. Many materials have properties that make them hazardous. They can create physical (fire, explosion) or health hazards (toxicity, chemical bums). However, there are many ways to work with chemicals which can both reduce the probability of an accident and reduce the consequences should an accident occur. Risk minimization depends on safe practices, appropriate engineering controls for chemical containment, the proper use of personnel protective equipment, use of the least amount of material necessary, and substitution of a less-hazardous chemical for a more hazardous one. Before beginning any chemical processing or operation, ask What would happen if. .. The answer to this question requires understanding of the hazards associated with chemicals, the equipment, and the procedure involved. The hazardous properties of the material and its intended use will dictate the precautions to be taken. 

Disposal of hazardous waste is dangerous and expensive, even when the contents of the waste are identified. Fortunately, most chemical waste produced in a laboratory or work area is identifiable. When the contents of a reagent bottle, reaction flask, or gas cylinder are not identified, the process of disposal is more dangerous, expensive, and difficult. Without mitigating information, all unknown materials must be treated as if they were potentially lethal and hazardous. In all cases, chemical unknowns cannot be disposed of until a general profile of the unknown has been generated. Even then, the disposal cost is a premium. Additionally, there is a constant threat of personal injury or death to individuals who handle these potentially dangerous materials. No price tag can be attached to an avoidable personal injury. 

Another important distinction to be known is the difference between hazard and risk. The two terms are sometimes used as synonyms. In fact, the term hazard is a much more complex concept because it includes conditions of use. The hazard presented by a chemical has two components (1) the inherent capacity 

Since there is no evaluation instrument that can identify the chemical or the amount of chemical contaminant present, it is not possible to be able to make a real-time assessment of a worker s exposure to potentially hazardous chemicals. Additionally, threshold limit values (TLVs) provided by the ACGIH in 1968 are the basis of OSH As PELs. In the early 2000s, workers are provided protection with chemical exposure standards that are 32 years old. The ACGIH regularly updates and changes its TLVs based on new scientific information and research. 

EPA allows for one death or one cancer case per million people exposed to a hazardous chemical. Certainly, the public needs these kinds of protections. Using the existing OSHA PELs risk factor is only as protective as one death due to exposure in 1000 workers. This indicates that there exists a fence line mentality, which suggests that woikers can tolerate higher exposures than what the public would be subjected to. As one illustration of this, the exposure to sulfur dioxide for 

OCCUPATIONAL HEALTH AND SAFETY MANAGEMENT A PRACTICAL APPROACH 

A piloted ignition source to obtain self-propagation of the flame must be available 

Most liquids respond to a temperature rise through a thermodynamic phase change to gas. For ignition to occur, the fuel concentration in air must be in a range that defines a flammable mixture. These bounding limits are commonly referred to as the lower flammability limit (LFL) and upper flammable limit (UFL). These are the lowest and highest fuel concentrations in air (by volume) that will support flame propagation. Fuel concentrations below the LFL or above the UFL are too lean or rich, respectively, and will not support combustion. 

Unstable chemicals are subject to spontaneous reactions. Situations where unstable chemicals may be present include the catalytic effect of containers, materials stored in the same area with the chemical that could initiate a dangerous reaction, presence of inhibitors, and effects of sunlight or temperature change. Examples include acetaldehyde, ethylene oxide, hydrogen cyanide, nitromethane, organic peroxides, styrene, and vinyl chloride. 

As an example, styrene polymerizes at ordinary temperatures and the rate of polymerization increases as temperature increases. The reaction is exothermic and becomes violent as it is accelerated by its own heat. Inhibitors are added to prevent the initiation of dangerous polymerization. When the styrene is used to fabricate materials, e.g., fiberglass resin, a catalyst may be added in the manufacturing process to initiate polymerization at a controlled rate. Any unbalance of these reactions in terms of quantities or temperatures could cause hazardous fire conditions. 

Chemicals that are water or air reactive pose a significant fire hazard because they may generate large amounts of heat. These materials may be pyrophoric, that is, they ignite spontaneously on exposure to air. They may also react violently with water and certain other chemicals. Water-reactive chemicals include anhydrides, carbides, hydrides, and alkali metals (e.g., lithium, sodium, potassium). 

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Process safety management of highly hazardous chemicals... 

M. Sittig, ed., Elandbook of Toxic and Hazardous Chemicals and Carcinogens, 2nd ed., Noyes Pubbcadons, Park Ridge, N.J., 1985. 

In a world increasingly conscious of the dangers of contact with chemicals, a process that is conducted within the walls of a vacuum chamber, such as the VDP process for parylene coatings, offers great advantages. Provided the vacuum pump exhaust is appropriately vented and suitable caution is observed in cleaning out the cold trap (trace products of the pyrolysis, which may possibly be dangerous, would collect here), the VDP parylene process has an inherently low potential for operator contact with hazardous chemicals. 

For chemical faciUties in the United States, hazard analysis is not an option if inventories of hazardous chemicals are maintained in amounts greater than the threshold quantities specified by the Occupational Safety and Health Administration (OSHA) regulation 1910.119. Many faciUties are finding that hazard analysis has many benefits. The process or procedure often works better, the quaUty of the product is improved, the process experiences less down time, and the employees feel more comfortable in the work environment after a hazard analysis has been completed. 

Manual of Hazardous Chemical Keactions No. 491, National Fire Protection Association, 1971. 

Chemical Hazards. Chemical manufacturers and employees contend with various ha2ards inherent ia productioa of evea commonplace materials. For example, some catalysts used ia the manufacture of polyethylene (see Olefin polymers) ignite when exposed to air or explode if allowed to become too warm the basic ingredient ia fluorocarboa polymers, eg, Tefloa (see Fluorine compounds, organic), can become violently self-reactive if overheated or contaminated with caustic substances (45,46) one of the raw materials for the manufacture of acryflc fibers (see Fibers, acrylic) is the highly toxic hydrogen cyanide (see Cyanides). 

Process Safety Management of Highly Hazardous Chemicals Tide 29, Subtitie B, Chapt. XVII, Part 1910, Subpart H, Paragraph 119, of the Code ofFederal Regulations (29 CER 1910.119), FederalRegisterhl >()) 6403, U.S. Department of Labor, Occupational Safety and Health Administration (Feb. 24, 1992). 

Health and Safety Factors. The strontium ion has a low order of toxicity, and strontium compounds are remarkably free of toxic hazards. Chemically, strontium is similar to calcium, and strontium salts, like calcium salts, are not easily absorbed by the intestinal tract. Strontium carbonate has no commonly recognized hazardous properties. Strontium nitrate is regulated as an oxidizer that promotes rapid burning of combustible materials, and it should not be stored in areas of potential fire hazards. 

Sodium Bisulfite, CHRIS Hazardous Chemical Data, Coast Guard, U.S. Dept, of Transportation, Washington, D.C., data sheet revised 1978. Treatment of Chromium Waste Eiquors, General Chemical Corp., Claymont, Del., 1989. 

The potassium hydroxide electrolyte used in alkaline batteries is a corrosive hazardous chemical. It is a poison and if ingested attacks the throat and stomach linings. Immediate medical attention is required. It slowly attacks skin if not rapidly washed away. Extreme care should be taken to avoid eye contact that can result in severe bums and blindness. Protective clothing and face shields or goggles should be worn when filling cells with water or electrolyte and performing other maintenance on vented batteries. 

Explosibility and Fire Control. As in the case of many other reactive chemicals, the fire and explosion hazards of ethylene oxide are system-dependent. Each system should be evaluated for its particular hazards including start-up, shut-down, and failure modes. Storage of more than a threshold quantity of 5000 lb (- 2300 kg) of the material makes ethylene oxide subject to the provisions of OSHA 29 CER 1910 for "Highly Hazardous Chemicals." Table 15 summarizes relevant fire and explosion data for ethylene oxide, which are at standard temperature and pressure (STP) conditions except where otherwise noted. 

Process Hazard Analysis (PHA) (Dowell, 1994, pp. 30-34.) The OSHA rule for Process Safety Management (PSM) of Highly Toxic Hazardous Chemicals, 29 CFR 1910.119, part (e), reqmres an initial PHA and an update every five years for processes that handle listed chemicals or contain over 10,000 lb (4356 kg) of flammable material. The PHA must be done by a team, must include employees such as operators and mechanics, and must have at least one person skilled in the methodology employed. Suggested methodologies from Process Safety Management are listed in Table 26-1. 

Inherent safety Inventory reduction Fewer chemicals inventoried or fewer in process vessels. Chemical substitution Substitute a less hazardous chemical for one more hazardous. Fr ocess attenuation Use lower temperatures and pressures. 

Understanding the chemistry of the process also provides the greatest opportunity in applying the principles of inherent safety at the chemical synthesis stage. Process chemistry greatly determines the potential impact of the processing facility on people and the environment. It also determines such important safety variables as inventory, ancillary unit operations, by-product disposal, etc. Creative design and selection of process chemistry can result in the use of inherently safer chemicals, a reduction in the inventories of hazardous chemicals and/or a minimization of waste treatment requirements. 

Bretherick s Handbook, NFPA 49, 325 and 432 hazard ratings, Sax, Handbook of Hazardous Chemical Properties, Kirk-Othmer Encyclopedia of Chemical Technology or as determined... 

Proof testing using non hazardous chemicals after making software changes... 

IRI 1990. Guiding Principals for Protection of High-Hazard Chemical and Petrochemical Plants. IRInformation Manual 17.2.1. Industrial Risk Insurers, Hartford, CT. 

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