Letters to the Editor: The L.A. Times’ shockingly unscientific editorial on declaring Tylenol a carcinogen

Acetaminophen, the key ingredient in painkillers like Tylenol, is under review by California’s Carcinogen Identification Committee.
(Joe Raedle / Getty Images)

To the editor: The public relies on the Los Angeles Times to keep powerful people honest by accurately reporting errors committed by government officials, captains of industry and (gulp) academics. So it is unnerving when The Times itself needs to be called out.

A Jan. 21 Times editorial took the California Environmental Protection Agency to task over the proposed assessment of the widely used painkiller, acetaminophen, saying that it is “way too soon to declare acetaminophen as a carcinogenic killer.” The piece implies that we should only identify carcinogens capable of causing “real” cancer.

As chairman of the state EPA’s Carcinogen Identification Committee for more than 25 years, I can say that the editorial is simply wrong. Like those who disparage vaccination and question global warming, the editorial sends the message that relying on science -- evidence, in other words -- is elitist, and that we are better off listening to (take your pick) Fox News or the neighborhood barber. This not only does a disservice to Californians, it also insults them.

The law on carcinogen labeling, passed by California voters as Proposition 65 in 1986, saves people from being exposed to potential cancer-causing agents and reproductive toxins without their knowledge. Potential carcinogens are first given priority using four criteria: credible suspicion, widespread exposure, no past definitive review by another national or international agency (“authoritative body”) and the availability of pertinent evidence not previously subjected to review.

Acetaminophen meets those criteria. It has a close chemical relative known to cause “real” renal pelvis cancer. It is occasionally used by virtually everyone worldwide, and it is used frequently by a substantial minority. It was last reviewed as a putative carcinogen by an authoritative body (the International Agency for Research on Cancer, or IARC) in 1999, and it could neither be indicted nor cleared of suspicion on the basis of the evidence. Since then, additional evidence has accumulated.

Now, the agency will convene a committee of California’s “qualified experts” on carcinogenicity (toxicologists, molecular biologists and epidemiologists). Using essentially the same process as the IARC, those experts will review all available chemical, animal and human evidence, none of which is ever definitive by itself. If a majority concludes that the agent has been “clearly shown through scientifically valid testing according to generally accepted principles to cause cancer,” the agent will be placed on the list of presumed carcinogens. The judgment will be made solely on evidence, expertise and experience, not considering usefulness or medical benefits. If the result is again unconvincing, there will be no action.


If the substance is judged to be carcinogenic, users should be warned, and responsibility passes from risk assessors to risk managers, who will estimate the levels of risk judged to be significant. If there is inconvenience, it will only be because informed and responsible people believe there to be unnecessary risk.

The members of the Carcinogen Identification Committee, from different institutions throughout the state, are responsible citizens; all have more personally rewarding things to do, but they devote time to this because they believe that human problems deserve the application of scientific evidence. In the course of each review, other relevant academics, industrial experts, clinicians, environmentalists, retailers, lobbyists and occasional laypersons weigh in to disagree with the expected committee decision, sometimes with evidence, sometimes not, and sometimes successfully, and sometimes not. They have all been aware of the distinction between the scientific recognition of a hazard and the implementation of an intervention.

The Times’ editorial on acetaminophen is the first time I can recall that a legitimate public voice, seemingly unaware of this difference between risk identification and risk management, has advocated ignorance and non-disclosure of a danger as a means of preventing control measures that might be inconvenient.

Perhaps no one should ever discover inconvenient dangers by reading the front page of The Times. Remember: Before science, cigarettes were fun and viruses only caused colds.

Thomas Mack, M.D, Los Angeles

The writer is a professor of preventive medicine and pathology at the USC Keck School of Medicine and chairman of the state’s Carcinogen Identification Committee.