Hazardous substances exposure protection

Radiation from a dirty bomb can emanate from a blast site in a contaminated plume of smoke or in contaminated debris. Radiation cannot be detected without special instruments, and radiation exposures can occur even without direct contact. Therefore, leaving a damaged building does not eliminate the risk of exposure. An effective tool to minimize or eliminate the potential for hazardous substance exposure is to move away from the site of the attack and into a building that provides protection from airborne contaminants. 

The ATSDR works to protect adverse human health effects from hazardous substance exposures from waste sites, unplanned toxic releases, and pollution sources present in the environment. Congress intended ATSDR to perform functions that include public health assessments of waste sites, health consultations concerning specific hazardous substances, applied research in support of public-health assessments, information development/dissemination, and education/training concerning hazardous substances. The agency reports administratively to the CDC. 

For hazardous substances not classified as carcinogens, where protection of exposure is not reasonably practicable, adequate control should be achieved by measures odier than personal protection, so far as is reasonably practicable. Tliis is subject to the degree of exposure, circumstances of use of the substance, informed knowledge about the hazards and current technical developments. Any combination of the measures listed in Table 5.22 are applicable. 

Medical monitoring and surveillance programs enable occupational health professionals to identify adverse health effects caused by exposure to hazardous substances and conditions and to discuss plans with site workers, industrial hygienists, safety professionals, and line management to prevent exposures and protect workers. These goals can be accomplished through two objectives ... 

Has the employer implemented the use of engineering controls, work practices, and personal protective equipment to reduce and maintain employee exposure to or below published exposure levels for hazardous substances and health hazards not regulated by 29 CFR Part 1910, Subparts G and Z (e.g., heat stress, lifting hazards) [OSHA Reference. 120(g)(2)]... 

It should be noted that the primary purpose of the ventilation systems described for abrasive blasting rooms and hospital isolation rooms is to prevent or minimize exposure to hazardous substances in those persons working outside the blasting or isolation room. The ventilation system may also reduce exposure for workers inside these rooms, but often the reduction is not sufficient to eliminate the need for respiratory protection. 

EL = emissions level ERA = Environmental Protection Agency HSDB = Hazardous Substances Data Bank lARC = International Agency for Research on Cancer IRIS = Integrated Risk Information System NIOSH = National Institute of Occupational Safety and Health OEL = occupational exposure limit OSHA = Occupational Safety and Health Administration PEL = permissible exposure limit RAC = reference air concentration REL = recommended exposure limit RCRA = Resource Conservation and Recovery Act RfD = reference dose TLV = threshold limit value TWA = time-weighted average WHO = World Health Organization... 

OSHA maintains a list of potential carcinogens. In addition, OSHA sets enforceable permissible exposure limits (PELS) to protect workers against the health effects of exposure to hazardous substances. 

The primary objective is to develop an appropriate range of waste management options to be analyzed more fully in the detailed analysis phase of the FS.12 Appropriate waste management ensures the protection of human health and the environment. It may involve, depending on site-specific circumstances, complete elimination or destruction of hazardous substances at the site, significant reduction of concentrations of hazardous substances to acceptable health-based levels, and prevention of exposure to hazardous substances via engineering or institutional controls, or some combination of the above. 

The New Jersey Department of Environmental Protection uses the TXDS method of consequence analysis to estimate potentially catastrophic quantities of toxic substances, as required by the New Jersey Toxic Catastrophe Prevention Act (TCPA). An acute toxic concentration (ATC) is defined as the concentration of a gas or vapor of a toxic substance that will result in acute health effects in the affected population and 1 fatality out of 20 or less (5% or more) during a 1-hr exposure. ATC values, as proposed by the New Jersey Department of Environmental Protection, are estimated for 103 extraordinarily hazardous substances and are based on the lowest value of one of the following (1) the lowest reported lethal concentration (LCLO) value for animal test data, (2) the median lethal concentration (LC50) value from animal test data multiplied by 0.1, or (3) the IDLH value. 

First Responder, Operations Level Individuals who respond to releases or potential releases of hazardous substances as part of the initial response to the site for the purpose of protecting nearby persons, property, or the environment from the effects of the release. They are trained to respond in a defensive fashion without actually trying to stop the release. Their function is to control the release from a safe distance, keep it from spreading, and prevent exposures. 

Shielding in this context refers to placement of a physical barrier between an individual and hazardous substances emanating from contaminated materials. In the field of radiation protection, shielding typically refers to a barrier that reduces radiation levels. The term is used in a broader sense here to refer to any physical barrier that reduces or eliminates exposure to a hazardous substance. Consider three rules of thumb for the shielding factor ... 

Three factors inherent in radiation protection philosophy (time, distance, and shielding) can be used to protect against exposure to hazardous substances released during a terrorist attack. The time factor refers to the duration of exposure. The distance factor refers to the physical separation (in feet, miles, etc.) between an individual and contaminated materials. The shielding factor refers to physical barriers between an individual and hazardous substances emanating from the attack location. 

From a scientific perspective, we work primarily with single exposures to chemicals to understand how the body reacts to a specific chemical. In real life, however, we are often exposed to a mixture of chemical agents. Multiple agents may interact and affect absorption or how the body reacts to the chemical. The body has a very sophisticated system to metabolize and eliminate chemicals from the body this system plays an important role in protecting us from hazardous substances. 

This document [63] also suggests exposure control measures in the following hierarchical form eliminate (i.e. avoid using hazardous substance), substitute (i.e. replace with less risky material), enclose (i.e. perform operations in enclosed cabins), engineering control (i.e. carrying out potential dust formation processes with extract ventilation), procedural control (i.e. limiting the number of personnel exposed, their time and the process to specified areas), and personal protective equipment (i.e. use of protection measures to limit inhalation and dermal exposure). 

The dominance of the risk to inadvertent intruders at near-surface waste disposal sites allows the use of this type of scenario to develop a risk-based waste classification system. However, NCRP recognizes that exposures of the public and protection of the environment also are of concern in determining acceptable disposal practices at specific sites. The potential for off-site releases of hazardous substances is the primary reason that classification of waste based on risks to hypothetical inadvertent intruders does not obviate the need for site-specific risk assessments to determine waste acceptance criteria in the form of limits on disposal of particular hazardous substances. 

The doses of hazardous substances at which responses can be observed in humans or animals are higher (sometimes by large factors) than doses relevant to waste disposal and other routine exposure situations. Therefore, most dose-response relationships at the low doses of interest in protection of human health are calculated rather than measured they are based not only on scientific data but also on various assumptions and extrapolation models which, while scientifically plausible, cannot yet be subjected to empirical study... 

The chemical paradigm also differs from the radiation paradigm in that there are no standards that apply to all controlled sources of exposure and all hazardous substances combined, as in radiation protection standards. Regulations for hazardous chemicals generally apply only to specific release pathways (eg., the atmosphere) or... 

NIOSH National Institute of Occupational Safety and Health. U.S. Congress set up this institute in 1970 to play a key role in the protection of the health of occupational workers. The agency conducts occupational health research, inspects industries and manufacturing plants at the request of the employers and workers, and collects data for their own studies, to recommend standards for safe exposure to hazardous substances. 

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