Risk Assessment and Risk 

 Management 



To aid users in accessing and understanding the data in the IRIS 

 chemical files, the following supportive documentation is provided: 



• Alphabetical list of the chemical files in IRIS and Ust of chemi- 

 cals by CAS (Chemical Abstracts Service) number. 



• Background documents describing the rationales and methods 

 used in arriving at the results shown in the chemical files. 



• A user's guide that represents step-by-step procedures for 

 using IRIS to retrieve chemical information. 



• An example exercise in which the use of IRIS is demonstrated. 



• Glossaries in which definitions are provided for the acronyms, 

 abbreviations, and specialized risk assessment terms used in 

 the chemical files and in the background documents. 



The information in IRIS is intended for use in protecting public health 

 through risk assessment and risk management. These two processes 

 are briefiy explained below. 



Risk assessment has been defined as "the characterization of the 

 potential adverse health effects of human exposures to environmental 

 hazards" (NRC, 1983, p.l8). In a risk assessment, the extent to which 

 a group of people has been or may be exposed to a certain chemical is 

 determined, and the extent of exposure is then considered in relation 

 to the kind and degree of hazard posed by the chemical, thereby 

 permitting an estimate to be made of the present or potential health 

 risk to the group of people involved. 



Risk assessment information is used in the risk management process 

 in deciding how to protect public health. Examples of risk manage- 

 ment actions include: deciding how much of a chemical a company 

 may discharge into a river; determining which substances may be 

 stored at a hazardous waste disposal facility; deciding to what extent a 

 hazardous waste site must be cleaned up; setting permit levels for 

 discharge, storage, or transport of hazardous waste; establishing levels 

 for air emissions; and determining allowable levels of contamination in 

 drinking water. 



Essentially, risk assessment provides information on the health risk,, 

 and risk management is the action taken based on that information. 



A complete risk assessment consists of the following four steps: 



1. Hazard identification, 



2. Dose-response assessment, 



3. Exposure assessment, and 



4. Risk characterization, 



with risk characterization being the transitional step to risk manage- 

 ment. 



