Purpose of this Guide:

EPA is aware of a general trend in industry to reduce or eliminate use of halogenated solvent cleaning systems. In addition, EPA knows that many firms now use or may soon begin using aqueous (water-based) and semi-aqueous (partially water-based) cleaning processes.

While use of these chemicals generally will be better for the environment, the chemicals can still be of concern when released to water. EPA hopes this guide will help minimize such adverse effects, and also focus solvent selection on a thorough consideration of costs, health effects, and effectiveness, as well as the persistence and ecotoxicity factors which are the focus of this guide.

Although metal-cleaning businesses often have access to information on human health effects, product effectiveness, and cost, more limited information is readily available on the environmental effects of alternative chemicals used in aqueous and semi-aqueous cleaning chemicals.

This guide and wall chart should help companies make environmentally responsible choices when choosing substitute cleaning systems by providing environmental effect and persistence information on some of the most commonly used alternative chemicals. It also refers the user to resources for health effects, toxicity, and process change information.

What This Guide Does:

How To Interpret The Ratings:

• High - 50% of organisms die at 1 part per million or less of the chemical.
• Moderate - 50% of organisms die at > 1 part per million, but less than or equal to 100 parts per million.
• Low - 50% of organisms die at > 100 parts per million.

Persistence ratings are based upon how long it takes the original chemical to completely break up into stable components when it is released to the environment. The ratings are:

• High - longer than 6 months to completely break up.
• Moderate - breaks up in less than 6 months, but longer than 1 month.
• Low - breaks up in 1 month or less.

Some Things To Consider When Using This Guide:

* Determining which solvent chemicals to use requires a careful balancing of the environmental, health, cost, and other factors with your needs for an effective cleaning product. This guide focuses on environmental factors only; check other resources (see Resources section) to ensure that you make a well-informed decision and consider all factors.

* Toxicity is generally more important than persistence.

* The percentage of each chemical in a formulation also must be considered when making substitution choices. For example, a cleaner containing a small percentage of a chemical with a high ecological toxicity rating may be less harmful to the environment than a cleaner with a large percentage of a moderate ranked chemical.

* The toxicity ratings in this guide are based on the specific chemical and do not consider the potential effects of combining more than one chemical in a formulation.

* The criteria for determining the ratings were based on either measured and/or predicted values for both ecological toxicity and persistence.

If you are unsure about which chemicals you are using, call your supplier for more information. To be sure the information you receive is correct, refer to the chemicals by their Chemical Abstracts Service (CAS) number, rather than chemical name, since chemicals often have more than one name.

Resources You Should Consult to Help Make Your Decisions: