Investigation Spotlight: Thallium and Kale Chips
Problem
In 2022, the California Department of Public Health (CDPH) was notified about a family with āyoung children that was experiencing neurological symptoms and had elevated levels of thallium in their urine laboratory test. Exposure to high amounts of thallium may cause several harmful health effects, including nervous system effects.
Investigation
Exposure to high amounts of thallium is rare since the U.S. banned its former usage as a rodenticide in 1972. To identify the source of the family's thallium exposure, CDPH surveyed the family about their diet and activities and worked with the U.S. Environmental Protection Agency to conduct on-site environmental testing. The environmental testing did not show anything unusual, but the dietary survey indicated the family consumed large amounts of a consumer brand of organic kale chips. Three separate samples of this brand of kale chips revealed elevated amounts of thallium in all three samples.
CDPH identified the kale chips as the likely source of the family's thallium exposure and the family was encouraged to stop eating the kale chips.
Outcomes and impact
When the family stopped eating the kale chips, the thallium levels in their urine decreased and their neurological symptoms improved.
CDPH turned its investigation over to the US Food and Drug Administration, which agreed to investigate the source of thallium in the kale chips. Additionally, CDPH petitioned the National Toxicology Program (NTP) to request a thorough toxicology study of thallium. Due to the lack of data on thallium from the NTP, state and federal food regulatory agencies do not know what an acceptable food standard or safety threshold should be for thallium.
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