PARIS III: EPA’s Solvent Substitution Software Tool

By Paul Harten, Ph.D.

Opening screen of EPA's PARIS III.


For decades, companies have used chemicals or solvents to improve the performance of their industrial processes. Unfortunately, many of these solvents are released as harmful wastes into our environment. EPA researchers are helping reduce that practice.

Recently, my colleagues and I developed a software tool, called PARIS III, that helps companies find alternate chemical mixtures or solvents that still improve their industrial processes but are not as harmful to our environment.

PARIS III stands for “Program for Assisting the Replacement of industrial Solvents, version 3.0”. Previous versions of the PARIS tool have been as effective, but this version has specifically been developed by the EPA as a free solvent substitution software tool. It can be used by any environmentally-conscious individual, including solvent technicians, industrial and solvent engineers, and environmental consultants.

The PARIS III database includes more than 4000 solvents commonly used by industry. In the search for replacements, it taps only those that have less environmental impact (greener), mixing them together in different proportions to find mixtures that perform as close as possible to the performance of those currently used by companies. The close replacement mixtures found can then be sorted to choose those mixtures that are least harmful to the environment.

To download and learn more about the tool, go to:

Learn more and download the tool at the website listed below.

The software uses the Environmental Index of solvent mixtures. That is a measure of a solvent mixtures’ impact on the environment, made by combining a various indicators, including human health, acid rain, and global warming. By looking at the ratio of the original solvent mixture’s Environmental Index to the Environmental Index of its replacement, you can get an estimate of how much harm to the environment will be avoided. For example, if the Environmental Index of the original solvent mixture is 10.0, and the Environmental Index of the replacement solvent mixture is 1.0, then using the replacement solvent instead of the original solvent will reduce harm to the environment by a factor of 10.0 to 1.0.

This solvent substitution software tool is provided by the EPA for free, and can be effective and efficiently used to help environmentally-conscious individuals find better and greener solvent mixtures for many different common industrial processes. Simply download and start using this tool at EPA’s website:

About the Author: EPA Physical Scientist Paul Harten has a Ph.D. in computational physics and a great amount of experience in computer science. He has been extensively involved with growth in the computer-oriented environmental sciences during his fifteen years with the Agency.

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