An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Worst-case “quantity released” reporting for a mixture

In section 2, element 2.5, of an RMP, facilities must report the quantity of toxic chemical that the facility used for the worst-case analysis. When reporting this data element in RMP*eSubmit for a mixture, should facilities report the entire weight of the toxic mixture potentially being released or only the amount of the regulated toxic substance in the mixture?

When reporting “Quantity Released” in section 2, element 2.5, of RMP*eSubmit, facilities are only required to include the amount of the regulated toxic substance in the mixture. This determination is consistent with the method for determining whether a threshold has been exceeded for a toxic substance in a mixture, whereby facilities need only consider the weight of the toxic substance in the mixture.

For additional information on quantifying toxic substances in mixtures, please see the Risk Management Program Guidance for Offsite Consequence Analysis (EPA 550-B-99-009) document located at: