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Chemical reference number (CAS): 7439-98-7

Molybdenum is a naturally occurring metal that is essential for life. It is found in small amounts in soil rocks, and water. Molybdenum is used to make cast iron, stainless steel, biofuels, solar panels, catalysts, lubricants, and pigments.

People are generally exposed to low levels of molybdenum daily. Most of this exposure comes from food. Low levels of molybdenum can also naturally be found in drinking water.

Higher levels of molybdenum may be found in the soil, air, and water near industries that make or use molybdenum compounds and near mines where molybdenum is sourced.


There are no standards for the amount of molybdenum allowed in the air of homes.


There are no federal or state drinking water standards for molybdenum.

Wisconsin has a groundwater enforcement standard of 40 micrograms per liter (µg/L) for molybdenum. However, the Department of Health Services (DHS) reviewed this standard in 2019 as part of the tenth cycle of groundwater standards. DHS recommends a groundwater standard of 60 micrograms per liter (µg/L) based on updated scientific information. DHS recommends that people take action to reduce exposure when the molybdenum level in drinking water are equal to or greater than 60 µg/L.

Everyone's Reaction is Different

A person's reaction to chemicals depends on several things, including individual health, heredity, previous exposure to chemicals, including medicines, and personal habits, such as smoking or drinking. It’s also important to consider the length of exposure to the chemical, the amount of chemical exposure, and whether the chemical was inhaled, touched, or eaten.


While low levels of molybdenum are required to maintain health, high levels may cause health effects.

Studies in research animals have shown that eating or drinking high levels of molybdenum can damage the kidneys and liver and affect reproduction and development.

Studies have also shown that breathing air with high levels of molybdenum can damage the inside of the nose and cause lung cancer.

The Agency for Toxic Substances and Disease Registry (ATSDR) has more information on exposure routes and health effects of molybdenum.

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Last revised May 4, 2022