Accidental Releases

In preliminary process design, the primary consideration is contact by inhalation. This happens either through accidental release of toxic material to the atmosphere or the fugitive emissions caused by slow leakage from pipe flanges, valve glands, and pump and compressor seals. Tank filling causes emissions when the rise in liquid level causes vapor in the tank to be released to the atmosphere. 

There are three types of TAP emissions continuous, intermittent, and accidental. Both routine emissions associated with a batch process or a continuous process that is operated only occasionally can be intermittent sources. A dramatic example of an accidental emission was the release of methyl isocyanate [624-83-9] in Bhopal, India. As a result of this accident, the U.S. Congress created Tide III, a free-standing statute included in the Superfund Amendments and Reauthorization Act (SARA) of 1986. Title III provides a mechanism by which the pubHc can be informed of the existence, quantities, and releases of toxic substances, and requires the states to develop plans to respond to accidental releases of these substances. Eurther, it requires anyone releasing specific toxic chemicals above a certain threshold amount to aimuaHy submit a toxic chemical release form to EPA. At present, there are 308 specific chemicals subject to Title III regulation (37). 

Effectiveness ofi Water Spray Mitigation Systems fior Accidental Releases ofiHydrogen Fluoride, Summary Report, National Technical Information Service, June 1989. 

A D—T fusion reactor is expected to have a tritium inventory of a few kilograms. Tritium is a relatively short-Hved (12.36 year half-life) and benign (beta emitter) radioactive material, and represents a radiological ha2ard many orders of magnitude less than does the fuel inventory in a fission reactor. Clearly, however, fusion reactors must be designed to preclude the accidental release of tritium or any other volatile radioactive material. There is no need to have fissile materials present in a fusion reactor, and relatively simple inspection techniques should suffice to prevent any clandestine breeding of fissile materials, eg, for potential weapons diversion. 

There are environmental concerns over the use of HE catalyst. The refining industry has taken steps to reduce the likelihood of an accidental release and to minimizp the environmental impact in the event of a release. As a result of these environmental concerns, most new units use sulfuric acid catalysts. 

Water Quality. AH commercial oil shale operations require substantial quantities of water. AH product water is treated for use and operations are permitted as zero-discharge facHities. In the Unocal operation, no accidental releases of surface water have occurred during the last four years of sustained operations from 1986 to 1990. The Unocal Parachute Creek Project compliance monitoring program of ground water, surface water, and process water streams have indicated no adverse water quaHty impacts and no violations of the Colorado Department of Health standards (62). 

U.S. Environmental Protection Agency, Risk Management Programsfor Chemical Accidental Release Prevention Proposed Rule Tide 40, Part 68, Subpart B, of the Code of Eederal Regulations (40 CER 68), Federal Register 54212 (Oct. 20,1993). 

Accidental Release Provisions. The 1990 CAAA includes provisions similar to OSHA s process safety management standard for minimi2ing the accidental release of air toxics. Based on types and quantities of ha2ardous chemicals on-site, a faciUty is required to develop and implement... 

Victims of overexposure to trichloroethylene should be removed to fresh air, and medical attention should be obtained immediately. A self-contained positive pressure breathing device should be used wherever high vapor concentrations are expected, eg, when cleaning up spills or when accidental releases occur. 

Introduction Theprevious sections dealt with techniques for the identification of hazards and methods for calculating the effects of accidental releases of hazardous materials. This section addresses the methodologies available to analyze and estimate risk, which is a function of both the consequences of an incident and its frequency. The apphcation of these methodologies in most instances is not trivial. A significant allocation of resources is necessary. Therefore, a selection process or risk prioritization process is advised before considering a risk analysis study. 

CCPS G-37. Understanding Atmospheric Dispersion of Accidental Releases. American Institute of Chemical Engineers, Center for Chemical Process Safety, New York. 

Has the facility identified, evaluated and implemented controls to reduce the risks associated with catastrophic chemical releases or accidental releases of regulated substances Look for evidence of the following ... 

Accidental Release Prevention Reqnirements Risk Management Programs nnder Clean Air Act Section 112(r)(7), Federal Register, Vol. 61, No. 120,Jnne 20, 1996. 

Accidental release An unintended or sudden release of chemicals) from manufacturing, processing, handling, or on-site storage facilities to the air, water, or land. 

Usually the effects of accidental releases are confined to the local scale. 

Accidental release, spillage Transport incidents Overfilling of containers Equipment failure Unexpected reactions Runaway reactions... 

As a standby for emergency use in case of accidental release of toxic materials, e.g. during tanker unloading, or disconnection of temporary pipelines or when dealing with spillages generally, or if other protective measures, e.g. local exhaust ventilation, fail in service. 

Investigate accidents which may have led to persons receiving effective doses in excess of 6 mSv or an equivalent dose greater than 30% of any relevant dose limit. Investigate and report to the authorities loss of materials from accidental release to atmosphere, spillages, theft. The Regulations provide a comprehensive list of notifiable concentrations for each radionuclide isotope. 

Adequate distance frequently serves to mitigate the consequences of an accidental release of chemicals, e.g. a flammable liquid spillage or toxic gas escape. 

A pesticide formulation plant should prepare and implement an emergency preparedness and response plan that takes into account neighboring land uses and the potential consequences of an emergency or accidental release of harmful substances. Measures to avoid the release of harmful substances should be incorporated in the design, operation, maintenance, and management of the plant. Pollution control equipment employed in this sector include baghouses for removal of particulate matter and carbon adsorption for removal of VOCs. 

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