Blog Entry

Backgrounders Published on Environmental & Health Risks of Chromium

Ramsey Hart

Canada Program Coordinator, 2008-2014

One of the world’s largest deposits of chromite (a mineral made up of chromium, iron and oxygen) has been found in a remote area of northern Ontario. US mining company Cliffs is developing plans and seeking government approvals and support for constructing a mine, transportation corridor, and processing facilities. Without a history of chromite mining in North America, and having read the Blacksmith Institute’s disturbing descriptions of the chromite industry in India, MiningWatch wanted to know more about this mineral and wanted to be able to share information with First Nations, potential workers, and the public who might be affected by these projects.

Our Research and Communications Intern Rachelle Gendron took on the task of doing an extensive literature review of the environmental toxicology of chromium. The results of her work are found in one comprehensive literature review and three shorter backgrounder papers all available online at

Through Rachelle’s work we’ve learned that chromium is a toxic metal and one form, chromium-6, is highly soluble and may be taken up by cells in plants and animals. Though most naturally occurring chromium is the less dangerous chromium-3, activities associated with mining and processing chromite can convert chromium-3 into chromium-6. This more toxic form may be released into the air, water or remain in solid wastes such as slag where it may leach into the environment over time.