Online Calculator Test

Feb. 1, 2024

The U.S. EPA proposed Maximum Contaminant Levels (MCLs) for key PFAS compounds on March 14.

However, the MCLs for four of those compounds aren't as simple as a single parts-per-trillion (ppt) measurement. Instead, EPA has proposed a "Hazard Index" approach, which measures the sum of four PFAS concentrations weighted against their respective Health-Based Water Concentrations.

The hazard index specifically concerns the following four compounds: perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), perfluorobutane sulfonic acid (PFBS), and hexafluoropropylene oxide dimer acid (HFPO-DA, also known as GenX Chemicals).

Below, you'll find a handy application that can calculate a water sample's potential hazard index score. To use it, simply type the number of each detected compound's concentration (in ppt), and the hazard index result will be generated automatically.

ppt

9.0 ppt
+

ppt

10.0 ppt
+

ppt

10.0 ppt
+

ppt

2000.0 ppt
+
=
0
Hazard Index (unitless)
This is not an official regulatory tool. This calculator is not meant to replace professional expertise, EPA oversight, or any components necessary for proper regulatory compliance.