US President Joe Biden announced on Wednesday that he has cancer, prompting the White House press office to quickly clarify that he was referring to skin cancer treatment he received prior to taking office last year.

The remark appeared to be a stunningly casual health announcement made during a speech about global warming in which the President mentioned emissions from oil refineries near his childhood home in Claymont, Del.

“That’s why I and so damn many other people grew up with cancer and why for the longest time Delaware had the highest cancer rate in the nation,” Biden said.

White House Spokesperson Andrew Bates directed The Washington Post to a tweet from Washington Post columnist Glenn Kessler, who said Biden had "non-melanoma skin cancers" removed before taking office.

How dumb is this tweet? Check out Biden's medical report. Before he became president, he'd had non-melanoma skin cancers removed. Has no one at @RNCResearch ever had this common procedure? https://t.co/TS9VWtKcYC https://t.co/itklkVZIor

— Glenn Kessler (@GlennKesslerWP) July 20, 2022

It's unclear why Biden chose to describe his cancer experience in the present tense. “He said ‘I have cancer’ in the present tense,” Greg Price of XStrategies LLC tweeted in response to Kessler.

Meanwhile, anarchist author Michael Malice joked, "Don't worry about Joe Biden having cancer, he is married to a doctor," referring to the fact that first lady Jill Biden uses the honorific "Dr." to refer to her doctorate in education, which she received in 2007.

Biden's physician clarifies 

Dr. Kevin O'Connor, Biden's physician, issued a health report last year that did not mention the President having any current cancers.

According to O'Connor's report, Biden's skin cancer was caused by time spent in the sun rather than exposure to chemicals used by the oil industry. “It is well-established that President Biden did spend a good deal of time in the sun in his youth,” O’Connor wrote of his patient, a former swimming pool lifeguard.

Read next: Biden's gaffes during summit: Ukrainians will not defeat Ukrainians!

“He has had several localized, non-melanoma skin cancers removed with Mohs surgery before he started his presidency. These lesions were completely excised, with clear margins,” the doctor added. But O’Connor also noted, “there are no areas suspicious for skin cancer at this time.”

Air pollution can aggravate skin conditions. However, it's unclear whether Biden had previously linked oil refineries to his skin growths, or whether medical experts had made that connection.

President's 'mental acuity' in question

Biden, 79, is the oldest President in US history, and his mental acuity is frequently questioned in public. He has stated, however, that he intends to run for a second term in 2024, barring ill health, and his supporters point out that he has struggled for years with gaffes or inaccurate remarks.

Biden frequently makes mistakes when attempting to establish a personal connection with his audiences.

Read next: Ex-White House Doctor Questions Biden's Mental State

Last year, Politico published a new poll in cooperation with the Morning Consult Center that showed only 44% of respondents approve of US President Joe Biden's job performance, while only 46% think he is "mentally fit".

Politico reported that voters are growing increasingly skeptical about the health and mental fitness of Biden, the oldest president ever sworn into the White House, according to the new poll.

Only 40% of voters surveyed agreed that Biden was "in good health", while 50% disagreed.

Read more: Biden becomes more unpopular among Americans: Poll