previous topic
Water Reactive
Glossary Index
Glossary Index
next topic
Free Sites FAQ's Regulations Glossary Software Suppliers
Books Forum Poll Fun stuff Quiz Store
Understand your MSDS with the MS-Demystifier Search ALL our MSDS info

WGK - Wassergefährdungsklasse
WHC - Water Hazard Class


The German Federal Water Management Act requires that substances be evaluated for negative influence on the physical, chemical or biological characteristics of water. These are classified into numeric water hazard classes (WGK or WHC depending whether you use the English or German acronym).

Additional Info

The water hazard potential is based on the properties of the substances (in particular acute oral toxicity for mammals), toxicity for aquatic organisms (mostly fish and bacteria) as well as biodegradability and bioaccumulation. The ranking is assigned by the Commission of the Evaluation of Water Hazardous Substances (KBwS) in which the German federal government, the German States and industry are represented.

ClassHazard Potential
"nicht wassergefährdend"
Not hazardous (formerly WGK 0)
1Slightly hazardous to water
2Hazardous to water
3Extremely hazardous to water

Any substance that falls in Classes 1, 2, or 3 is referred to as awg (hazardous to water in general).

Classification of substances into Water Hazard Classes is discussed in the resources listed under Further Reading below. A working knowledge of German will be a big help.

SDS Relevance

The WGK abbreviation commonly appears on Safety Data Sheets for products that are sold in the European Community (EC). If present, this information is generally found in Section 15 (regulatory information), however it may also appear in Section 12 (ecological information).

In the United States, the data required for SDS Sections 12 through 15 falls outside OSHA's purview, so these sections are non-mandatory (optional). OSHA requires only that these headings appear on the sheet but does not require that any information be entered under sections 12 through 15.

Further Reading

How much water do I need sign with bottles

Help your workers beat dehydration with heat stress prevention signs from Safety Emporium.

See also: acute toxicity, ANSI, biolgical oxygen demand, CHIP, heavy metal.

Additional definitions from Google and OneLook.

Entry last updated: Monday, February 7, 2022. This page is copyright 2000-2023 by ILPI. Unauthorized duplication or posting on other web sites is expressly prohibited. Send suggestions, comments, and new entry desires (include the URL if applicable) to us by email.

Disclaimer: The information contained herein is believed to be true and accurate, however ILPI makes no guarantees concerning the veracity of any statement. Use of any information on this page is at the reader's own risk. ILPI strongly encourages the reader to consult the appropriate local, state and federal agencies concerning the matters discussed herein.