At long last, Science retracts controversial, hyped up paper on ‘arsenic life’

In the controversial 2010 paper on “arsenic life”, the authors did not indulge in any deliberate fraud or misconduct. But two failed attempts to replicate the findings proved that the conclusions were based on contamination. The paper was retracted as the key conclusion of the paper is based on flawed data 

Nearly 15 years after the controversial paper on a bacterium using arsenic instead of phosphorus by Felisa Wolfe-Simon from NASA Astrobiology Institute, U.S. and others was published online in the journal Science on December 2, 2010, the paper was retracted on July 24, 2025.

The paper claimed that a bacterium isolated from California’s Mono Lake was capable of substituting arsenic for a small percentage of phosphorus and still sustaining its growth. It was a tall claim — arsenic is only a toxic element and hence is not one of the six elements (carbon, oxygen, hydrogen, nitrogen, sulphur, and phosphorus) that make up most of the organic molecules in living matter.

Hyping up science

The paper was born with a controversy — hyping up science. The reason: A media advisory sent out by NASA on November 29, 2010 said a press briefing will be held on December 2, 2010 to “discuss an astrobiology finding that will impact the search for extraterrestrial life.” In the press conference, NASA claimed that the finding is proof of “arsenic life”, a breakthrough in astrobiology.

“I’d like to introduce to you today the bacterium GFAJ-1,” Wolfe-Simon said during the press briefing. “We’ve cracked open the door to what’s possible for life elsewhere in the universe. And that’s profound.” Another panellist, Mary Voytek, NASA’s astrobiology programme director in 2010 said: “It sounds to me like you you’re going to need to go out and find a new textbook to teach all those students about what elements are used to build life.”

However, the paper itself did not mention the possibility of life outside Earth nor the accompanying news item published in the journal propose anything of that kind, NASA’s press briefing ensured that there was media sensation. But the scientific community reacted to the paper with great skepticism. The journal was flooded with Comments pointing out the flaws with the paper.

In an Editor’s note published on June 3, 2011, Bruce Alberts said that the journal has “received a wide range of correspondence that raised specific concerns about the research article’s methods and interpretations.” The paper was published in print on June 3, 2011 issue along with eight Technical Comments, a Technical Response from the authors and the Editor’s note. The Editor’s note said: “the publication of this collection will allow readers to better assess the research article’s original claim and the criticisms of them.” Alberts also added that the authors are making the bacterial strain available for others to test their hypothesis in the “usual way that science progresses”.

Failed attempts to replicate findings

A year later, Science published two papers (here and here) that clearly showed that “arsenic life” was simply wrong. One study found that the bacterium needed a low level of phosphate (1.6 µM) to grow at all. And instead of incorporating a significant amount of arsenic, the bacterium’s nucleic acids “acquired a trace of arsenic”. The second study found that the bacterium was unable to grow in the absence of phosphate, and its growth was “not stimulated by the addition of arsenate”. However, a trace amount of arsenic was also detected in DNA. The Technical Report pointed out the presence of phosphate in the growth medium and the absence of the important DNA purification steps that “cast doubt on the authors’ conclusion”.  

The Editor’s blog published on July 24, 2025 along with the retraction notice says: “Given the evidence that the results were based on contamination, Science believes that the key conclusion of the paper is based on flawed data.” The blog post goes further to add: “At no point has there been any discussion or suggestion at Science of research misconduct or fraud by any of the authors.” But the attack on Wolfe-Simon was relentless, especially online.

Hinting about retraction in February 2025

Posting on LinkedIn in February this year, Holden Thorp, Editor-in-Chief of Science wrote: “Science initially published a large set of technical comments and the two failed replications but did not retract the paper. That was consistent with the norms at the time. As this paper continues to be discussed prominently, Science is of the view that the paper should be retracted. We have not done so yet, because we are working with the authors to ensure that they have every opportunity to understand our position and to make any additional arguments. We believe this level of care is appropriate given the long saga that has taken place.”

On February 11, 2025 Holden Thorp told The New York Times that “We feel the best thing to do would be to retract the paper.” 

Based on records received from NASA under a Freedom of Information Act, Dan Vergano from the USA Today found that the peer-review reports were “positive, enthusiastic”. However, the Editor’s blog says “a number of factors led to the publication of a paper with seriously flawed content, including the peer review process and editorial decisions that we made”. And the retraction was to “acknowledge and take responsibility for the role that we played in the paper’s publication”.

No deliberate fraud

It must be noted that despite the paper having serious flaws, the authors had not indulged in any fraudulent research. The flaws in the papers were honest mistakes and not deliberate attempts to fake or fabricate data or research. Yet the paper was retracted in 2025. Explaining the reason for retracting it after 15 years, the retraction note by Holden Thorp says: “Science did not retract the paper in 2012 because at that time, Retractions were reserved for the Editor-in-Chief to alert readers about data manipulation or for authors to provide information about post-publication issues. Our decision then was based on the editors’ view that there was no deliberate fraud or misconduct on the part of the authors. We maintain this view, but Science’s standards for retracting papers have expanded. If the editors determine that a paper’s reported experiments do not support its key conclusions, even if no fraud or manipulation occurred, a Retraction is considered appropriate.”

The authors have disagreed with the retraction. “We do not support this retraction. While our work could have been written and discussed more carefully, we stand by the data as reported. These data were peer-reviewed, openly debated in the literature, and stimulated productive research,” the authors say in the eLetter. “The editors’ basis for retraction is that the ‘paper’s reported experiments do not support its key conclusions’. No misconduct or error is alleged. This represents a major shift from the standards Science adhered to in the past, which aligned with those of the Committee on Publication Ethics (COPE).”

Writing on Substack, Holden Thorp says that since 2019, Science has retracted 20 papers, of which “11 [papers] were for honest error and two of those were retracted against the wishes of at least some of the authors”. And responding to queries whether Science would now start probing other problematic papers, he says that a decision to retract a paper is taken based on two factors — “concerns raised that are sufficiently specific that we can investigate them” and the second is that the journal should have “access to enough information to make a judgment on our own without involving the institution or authors”. And in this case, he claims that “both of these conditions hold”.

Reactions

“It’s good that it’s done. Pretty much everybody knows that the work was mistaken, but it’s still important to prevent newcomers to the literature from being confused,” microbiologist Rosie Redfield, a prominent critic of the study after its publication in 2010 and who now retired from the University of British Columbia in Vancouver, Canada, told Nature News. Taking a contradicting stand, Ariel Anbar, a coauthor of the 2010 paper from Arizona State University in Tempe, told Nature News that the paper had no mistakes in the data and that the data could be interpreted in many ways. “You don’t retract because of a dispute about data interpretation”, and if the same standard is applied to all published papers, then “you’d have to retract half the literature”, he said.