Mixing of Incompatible Chemicals

Expand the existing Responsible Distribution Process to include reactive hazard management as an area of emphasis. At a minimum, ensure that the revisions address storage and handling, including the hazards of inadvertent mixing of incompatible chemicals. 

Color-coded buckets and storage locations protect against inadvertent mixing of incompatible chemicals. 

Exposure to the public and the environment from certain chemicals may result in serious short and long term consequences. Events that can precipitate a chemical release from a warehouse include fire, on-site accidents, natural perils, or accidents involving trucks making deliveries to or from the warehouse. These events may result in dispersion of hazardous chemicals throughout the surrounding community, particularly if a release involves smoke, vapors, or gases. A hazardous release may involve the actual chemicals stored, reaction products from chemical decomposition, or mixing of incompatible chemicals, or products of combustion. 

Another type of safe limit is to do with the mixing of incompatible chemicals. Mixing tables such as that given in Table 1.6 are commonly used to ensure that only compatible chemicals... 

The assumption underpinning the incident pyramid is that the causes for all types of event are the same. In fact, this assumption is only partially correct because the root causes of minor events are different from those that lead to process safety events. Therefore, improving day-to-day safety will not necessarily reduce the number of serious incidents. Minor events are typically caused by occupational problems such as trips and falls, lack of proper PPE, and improper use of machinery. Major events, however, are more often caused by process safety problems such as incorrect instrument settings, corrosion, or mixing of incompatible chemicals. Hence a program that leads to improvements in occupational safety will not necessarily help reduce the frequency of process-related events. Indeed, improvements in the occupational safety record may induce a false sense of confidence regarding the potential for a major event. (It is probable, however, that a poor performance in occupational safety will correlate positively with a poor performance in process safety.)... 

Reverse Flow can create high-consequence hazards because it can lead to the mixing of incompatible chemicals or to the introduction of corrosive chemicals into equipment not designed for them. The cause of Reverse Flow is usually a pressure reversal — a high-pressure section of the process loses pressure process fluids then flow into that section back from low-pressure sections of the process. (The occurrence of reverse flow almost invariably imphes that a check valve and/ or safety instrumented system has failed to prevent the event)... 

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. 

Concise guidance targeted at companies engaged primarily in the bulk storage, handling, and use of chemicals to prevent inadvertent mixing of incompatible substances. 

The Whitehall Leather case demonstrates that reactive hazards other than thermal runaways in reactors-such as inadvertent mixing of incompatible materials-can cause severe reactive incidents. Neither ferrous sulfate nor sodium hydrosulfide is rated by NFPA, and neither compound is an OSHA PSM-listed chemical. 

Certain hazardous chemicals when stored or mixed together react violently. These chemical substances are unsuitable for mixing and are incompatible. During storage, classes of incompatible chemicals should be segregated from each other according to hazard class. In chemical laboratories, more often than not chemicals are stored alphabetically. This has led to the occurrence of several chemical disasters and explosions. It is important that incompatible chemical substances be handled, stored, and disposed of with care and caution and that no contact is made from one chemical to the other. The following are a few selected incompatible chemical substances. Chemicals in coiumn A should not come in contact with chemicals in coiumn B ... 

Chemical Factors. There are several mechanisms to damage a formation that involve chemical factors. The most important and well defined mechanisms are the following (1) fines migration and clay swelling, (2) mixing of incompatible waters, and (3) corrosion products. A brief discussion of each mechanism follows. 

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