Mercaptobenzothiazole Information


Mercaptobenzothiazole (MBT)

Other Names


Chemical Formula


CAS Number

149 – 30 – 4

Industry Uses

Corrosion inhibitor

Health Risks

Allergen; Contact Dermatitis; Possible Carcinogen


What is MBT?

MBT is formulated with various water treatment products to prevent corrosion of copper and copper-containing metals. These tests are well-suited to the monitoring of closed-loop cooling water systems and utility condensers where high MBT concentrations are usually maintained. MBT is very toxic to aquatic life and leaves long-lasting damage to it.

MBT Exposure and Health Risks

MBT is a chemical allergen, causing a reaction of increased histamine release and cell-mediated immunity, as well as skin reactions. It is very irritating to eyes and skin. MBT is also a probable carcinogen and is harmful by inhalation, ingestion, and absorption. When heated to decomposition, the fumes it emits are highly toxic.


There are no listed regulations or restrictions for levels of MBT in water. 

Measuring MBT

Dissolved MBT concentration in water can be measured in units of parts per million (ppm). We carry a kit from CHEMetrics that determines MBT levels in water, ranging from 50-500 ppm. Our MBT products can be viewed HERE.

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