What is hexavalent chromium? The toxic compound spilled into Huron River, found in I-696 green ooze

Odorless, tasteless metallic element used in industry

Huron River (L), Green ooze on I-696 (R) (WDIV)

A compound known to cause cancer was released into the Huron River system this week.

That compound is hexavalent chromium. It’s the same compound that was found in “green ooze” that was leaking onto I-696 in 2019.

But what even is hexavalent chromium? It’s a form of chromium, an odorless and tasteless metallic element found naturally in rocks, plants, soil, volcanic dust and animals.

According to the EPA there are two main forms of chromium:

  • Trivalent chromium (chromium-3)
  • Hexavalent chromium (chromium-6)

The EPA said that trivalent chromium is an essential human dietary element and can be found in many vegetables, fruits, meat, grains and yeast.

Hexavalent chromium occurs naturally in the environment from the erosion of natural chromium deposits and can also be produced by industrial processes.

It can be leaked into the environment by leakage, poor storage or inadequate industrial waste disposal practices, according to the EPA.

How is hexavalent chromium used?

Chromium compounds are widely used in electroplating, stainless steel production, leather tanning, textile manufacturing and wood preservation.

It’s used as pigments in dyes, paints, inks and plastics. It can also be used as an anticorrosive agent added to paints, primers and other surface coatings.

It’s also used to electroplate chromium onto metal parts to provide a decorative or protective coating.

The United States is one of the world’s leading producers of chromium compounds, according to the NIEHS.

The CDC said that the following workers are most at risk of being exposed to hexavalent chromium:

  • Welders working with carbon and stainless steel welding
  • Steel mill workers in iron and steel foundries
  • Workers who work with or near wet cement
  • Employees working in the electroplating, wood preservation, or textile dyeing industries

Chromium in drinking water

The Maximum Contaminant Level (MCL) for chromium was established in 1991 after research indicated that continued exposure could cause skin reactions.

The current federal drinking water standard for both forms of chromium is 0.1 mg/l or 100 ppb.

They are both covered under the total chromium drinking water standard because, according to the EPA, both forms of chromium can convert back and forth in water and in the human body, depending on environmental conditions.

When environmental officials test for chromium in the water, they always assume that the measurement is 100% hexavalent chromium. That’s because it’s more toxic and they want to ensure the risk is addressed appropriately.

Health effects of hexavalent chromium

Hexavalent chromium is a known human carcinogen -- it can cause cancer, according to OSHA.

The compounds have been shown to cause lung cancer in humans when inhaled.

According to the NIEHS, studies have shown increased lung cancer rates in workers who were exposed to high levels of chromium where they work.

Other health effects from exposures include nasal and sinus cancers, kidney and liver damage, nasal and skin irritation, ulceration, eye irritation and damage.

Green ooze on I-696

A “green ooze” was found leaking onto I-696 in 2019, the substance was identified as hexavalent chromium.

Officials said the chemicals were being improperly stored in the basement of a building in Madison Heights. It seeped through the soil and leaked out onto the freeway.

The owner of the building, Gary Sayers, pleaded guilty to storing chemical waste in the basement of the building without a permit.

Demolition on the building was expected to start this year and could take months to complete.

Officials said drinking water in the area was not impacted by the leak.

Read more: Demolition of building behind ‘green ooze’ spill in Madison Heights underway

Huron River contaminated

Hexavalent chromium was released into the Wixom Sewage Treatment Facility from Tribar Manufacturing -- water from the treatment facility is released into the Huron River System.

The Michigan Department of Environment, Great Lakes, and Energy was notified at 3:21 p.m. Monday (Aug. 1) by Tribar that it had released several thousand gallons of liquid containing 5% hexavalent chromium into the sewer system.

The company said it discovered the release on Monday, but believed it could have started as early as Saturday morning. Officials believe much of the contaminant already made its way through the treatment plant.

Because of the leak, health officials are warning people to stay out of parts of the Huron River while they investigate the leak.

Officials said “there is no immediate threat to drinking water” in the area. Ann Arbor has been notified of the leak and taking steps to monitor the water.

Read more: Officials warn people not to swim, fish in Huron River due to cancer-causing chemical

What can you do to protect yourself?

If you live near a site where chromium compounds are disposed of or manufactured you should work with public health officials to find out if it’s present in the water, air or soil where you live.

Children should never play in soils near uncontrolled hazardous waste sites where chromium may have been discarded.

Sources: NIEHS, National Cancer Institute, EPA, Department of Labor, CDC, OSHA

About the Author:

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.