Frequently Asked Questions
This page represents the most commonly approached topics from our users.
What internet browser works best for the RAIS?
We attempt to accommodate every browser. If there is a problem viewing the RAIS pages or downloading items, let us know what browser you are using and we will try and fix the problem.
How can I use the information on the RAIS?
The information on the RAIS can be used for teaching material and performing risk assessments that comply with EPA guidance. Feel free to use the information; it is available to the public. However, please give proper credit to the RAIS and the team from Oak Ridge National Laboratory and The University of Tennessee where you see fit. Also, the databases we maintain are updated on a quarterly basis or sooner, so you may need to "time-stamp" any information you download.
Is there a version of the RAIS I can download to my laptop?
No, the RAIS databases are solely an internet service. If you wish to have a stand alone software package for your laptop or desktop PC that performs many tasks similar to the RAIS, please download SADA (Spatial Analysis and Decision Assistance). This software was developed with the same databases and equations used by the RAIS. Spatial Analysis and Decision Assistance (SADA) is free software that incorporates tools from environmental assessment fields into an effective problem solving environment. These tools include integrated modules for visualization, geospatial analysis, statistical analysis, human health risk assessment, cost-effective analysis, sampling design, and decision analysis.
How are the toxicity values and other parameters maintained?
The toxicity values are reviewed monthly and manually updated when IRIS and HEAST release new values. The What's
New link will tell you when a value has been updated. Besides toxicity values, we also maintain Regulatory ARARS
How can I get further training on the RAIS and risk assessment?
The RAIS Team has developed one to five day risk assessment courses that use the RAIS. We can modify these courses to meet any clients needs. Contact an RAIS representative. Please remember the RAIS already has 3 online training platforms 1) What is Risk Assessment? 2) RAIS Main Tutorial, and 3) Risk Assessment Overview Diagram.
Where else can I go for toxicity studies (values) not on the RAIS?
A website similar to the RAIS is the ITER database at http://www.tera.org/iter/. ITER is the International Toxicity Estimates for Risk. It is managed by TERA (Toxicology Excellence for Risk Assessment) Please direct any e-mail questions to Andrea at Wullenweber@tera.org. TOXNET is a cluster of databases on toxicology, hazardous chemicals, and related areas hosted by the National Library of Medicine. Websites of other governmental agencies are also useful. Call the U.S. EPA Superfund Health Risk Technical Support Center at (513) 569-7596 and ask for toxicity values. Call the ATSDR Information Center toll-free at 1-888-422-8737 for toxicity values and profiles. Also try NIOSH, WHO, OSHA for exposure standards. For information on nerve agents contact DENIX.
Also try the IRIS hotline at:
Phone: (202) 566-1676
Where can I get more info on ecological risk assessment?
Please go to the RAIS ecological benchmark page. Here you will find a link to many ecological screening benchmarks and a link to ORNL Environmental Science Division website. This website should be helpful in providing information about water, soil and air exposures to many ecological endpoints.
Does the RAIS provide specific information regarding risk to children?
The easy answer is, "yes it does." The real answer is , "yes and no". "Yes," in the sense that the exposure to the child is considered in the equations for a total lifetime of exposure; as well as separately considering the child's exposure for soil and milk ingestion. The "no" part of the answer relates to the fact that there are few environmental studies on child acute exposures and the RAIS reflects the current state of knowledge and does not present a standardized approach for acute child risk assessment for any/all chemicals. Some individual chemicals, e.g. lead, pesticides (indoor use), or radionuclides, will have specific approaches to assess child risks. If you wish to further investigate, there are several diverse regulations on child risk assessment (EPA, FQPA, CPSC, etc.).
What do GIABS, TEF and ABS stand for and where do the values come from?
GIABS stands for GastroIntestinal Absorption Factor. The GIABS value is used to convert oral slope factors (administered dose) to dermal slope factors (administered dose) by factoring out the percentage eliminated in bodily waste. TEF stands for Toxicity Equivalence Factor. The TEF is used to convert the total amount of toxic dioxin and furan congeners present at a site as toxic equivalents (TEQ) of 2,3,7,8-tetrachlorodibenzodioxin (TCDD) present. TEFs are also used for polycyclic aromatic hydrocarbons to give a relative potency of each compound relative to that of benzo(a)pyrene. ABS stands for ABSorption Factor. ABS values are used in estimating the various chemical uptake efficiencies associated with dermal exposure to contaminated soils. Our ABS values come from U.S. EPA RAGS Part E Exhibit 3-4. Our TEF values come from a U.S. EPA 2013 memo on Use of Dioxin TEFs in Calculating Dioxin TEQs at CERCLA and RCRA Sites. Additional information is provided in the chemical RG User's Guide in section 2.3.4. GIABS default values are given in RAGS Part E Exhibit 4-1.
Where can I find out about the sources for Chemical-Specific Factors?
Our main source for these factors is SRC PhysProp Database.Our secondary source for these factors is EPI Suite. These programs help retrieve various chemical-specific parameters such as BP, MP, VP, H, S, log p, Koc, BCF, MW and Kp. WATER8 and CHEMDAT8 database programs are no longer maintained by EPA. The RAIS may still contain some information from WATER8. CHEM9 is a compound properties processor that is based upon an EPA compound database of over 1000 compounds. Here is the web address for WATER 9 which replaced CHEM 9. It provides the capability to estimate compound properties that are not available in the database, including the compound volatility, diffusivity in air, and diffusivity in water. The RAIS also uses CRC, Perry's, Yaws, the HSDB, and other sources as necessary. See the chemical PRG User's Guide section 2.4 for more details.