The authors of a paper that went viral with attention-grabbing headlines urging people to throw out their black plastic kitchen tools have corrected the work for a second time.
But a letter accompanying the correction suggests the latest update still fails “to completely correct the math and methodological errors present in the study,” according to Mark Jones, an industrial chemist and consultant who has been following the case. “The errors are sufficient to warrant a restating of the abstract, sections of the paper and conclusions, if not a retraction.”
The paper, “From e-waste to living space: Flame retardants contaminating household items add to concern about plastic recycling,” originally appeared in Chemosphere in September. The study authors, from the advocacy group Toxic-Free Future and the Amsterdam Institute for Life and Environment at Vrije Universiteit Amsterdam, looked for the presence of flame retardants in certain household plastic items, including toys, food service trays and kitchen utensils.
The researchers found toxic flame retardants in several items that wouldn’t ordinarily need fire protection, such as sushi trays, vegetable peelers, slotted spoons and pasta servers. Those items, the authors suggested, could have been made from recycled electronics — which do contain flame retardants.
Then, for kitchen utensils, the authors used findings from another study, which measured how toxic chemicals including BDE-209 transfer from black plastic utensils into hot cooking oil, to estimate potential intake based on findings in their own study. They estimated a daily intake of 34,700 ng/day of BDE-209 from using contaminated utensils, which “would approach the U.S. BDE-209 reference dose” set by the Environmental Protection Agency, they reported.
But the authors miscalculated that reference dose. They had put it at 42,000 ng/day instead of 420,000 ng/day. That hiccup led to the first correction to the paper, published in December. “This calculation error does not affect the overall conclusion of the paper,” the authors said in the corrigendum.
The latest corrigendum, published July 3, states the formula the authors used to estimate exposure to the flame retardant BDE-209 “was misinterpreted.” It continues:
This misinterpretation led to an overestimation of the BDE-209 exposure concentration. The corrected estimated BDE-209 exposure is 7900 ng/day instead of 34,700 ng/day.
“While we regret the error, this is a correction in one exposure example in the discussion section of the study,” lead author Megan Liu of Toxic-Free Future told us by email. “The example was not part of the core research objectives or methods of the study.”
Jones, who spent his career at Dow Chemical, told us the second corrigendum is “inadequate and still incorrect.”
“If the error is sufficiently large to only provide context, the statement in the Conclusions that brominated flame retardants ‘significantly contaminate products’ no longer can be supported and must be corrected or retracted following the reasoning presented in the second corrigendum,” Jones wrote in a letter to the editor published with the second correction.
Jones took to task some of the calculations and other estimates Liu and colleagues made, which the authors refute in a response to Jones’ letter, also published in Chemosphere this week.
The Elsevier journal was delisted from Clarivate’s Web of Science in December for failing to meet editorial quality criteria. Last December an Elsevier spokesperson told us the publisher’s ethics team was“conducting in-depth investigations” of “potential breaches of Chemosphere’s publishing policies.” The journal had published more than 60 expressions of concern in 2024 and has retracted 34 articles so far this year.
Part of delisting means Clarivate no longer indexes the journal’s papers or counts its citations. Google Scholar shows seven citations to Liu’s paper, and Dimensions lists four scholarly citations.
Like Retraction Watch? You can make a tax-deductible contribution to support our work, follow us on X or Bluesky, like us on Facebook, follow us on LinkedIn, add us to your RSS reader, or subscribe to our daily digest. If you find a retraction that’s not in our database, you can let us know here. For comments or feedback, email us at [email protected].