When Donald Trump proposed injecting disinfectant to treat the coronavirus during his latest White House news conference, the president was immediately slammed by medical experts for promoting ‘dangerous’ and unfounded science.

Dr Deborah Birx, his own scientific advisor and coronavirus task force response coordinator, appeared visibly stunned on Thursday evening as president Trump suggested it “would be interesting” to check whether ultraviolet light and disinfectant might weaken the Covid-19 disease that has now infected more than 890,000 Americans and left 50,999 dead.

“This is one of the most dangerous and idiotic suggestions made so far in how one might actually treat COVID-19,” said Paul Hunter, a professor of medicine at Britain’s University of East Anglia.

American pulmonologist Dr Vin Gupta meanwhile told NBC News: “This notion of injecting or ingesting any type of cleansing product into the body is irresponsible and it’s dangerous”.

Citing responsibility over public safety on Friday, the manufacturer of cleaning brands Dettol and Lysol was forced to issue a statement saying ‘under no circumstances’ should their products be consumed.

The White House later said that Mr Trump’s comments on Thursday were taken out of context and that neither UV lighting or disinfectant was under consideration to treat coronavirus.

The president's bogus claims on coronavirus treatment came as he admitted that he was not a doctor. “I'm not a doctor. But I'm, like, a person that has a good you-know-what,” said Trump, pointing to his head.

But it is not the first time he has discussed ‘dangerous’ scientific theories and claimed unfounded expertise throughout his presidency.

Thursday’s comments came after weeks of the president having promoted hydroxychloroquine, which he claimed could be a “gamechanger” in the United States’ battle against Covid-19.

With emphasis on the “if”, Trump told reporters at the beginning of April: “If this drug works, it will be not a game changer because that's not a nice enough term. It will be wonderful,” he said. “It will be so beautiful.”

Hydroxychloroquine continues to be an unproven treatment for coronavirus, and on Friday the US Food and Drug Administration warned Americans that the drug should not be consumed outside of hospital settings.

That comes less than three weeks after Mr Trump asked Americans "what they had to lose" by taking the pill, now deemed to be a cause of "serious poisoning and death," by the FDA.

At other times, Mr Trump has described himself as an "expert" on energy, and made unconfirmed claims about the safety of light bulbs.

The Trump administration’s roll-back on environmental standards has centered around an obsession with light bulbs, which he claimed at a rally in October made him look orange.

"The bulb that we're being forced to use, number one, to me, most importantly, I always look orange," the president told a Republican audience in Baltimore.

Mr Trump has maintained that Democrats had "taken away’" older incandescent bulbs which he admitted made him look “better” during a campaign rally in Rio Rancho, New Mexico, in September 2019.

“They [Democrats] took away our lightbulb. I want an incandescent light. I want to look better, okay? I want to pay less money to look better. Does that make sense?”

Those comments come as the Trump administration overturned Obama-era rules that would have banned the sale of most traditional incandescents by 1 January, 2020.

“You get a much better light at a much reduced cost,” boasted Mr Trump in September, before making an unfounded claim that greener energy efficient light bulbs were damaging to health.

“Because when those other bulbs break they really are dangerous. The gases come out, they’re dangerous,” said the president.

Mr Trump first delved into the issue in 2012, tweeting unfounded claims energy efficient bulbs are carcinogenic.

“Remember, new ‘environment friendly’ lightbulbs can cause cancer. Be careful - the idiots who came up with this stuff don't care,” claimed Trump.

Whilst the debate around hazardous levels of mercury in fluorescent light bulbs (CFLs) has continued throughout the past decade, data from the National Electrical Manufacturers Association reported that sales of CFLs accounted for less than 5 per cent of all sales of classic lightbulbs in the US in 2019.

In comparison, modern LED energy efficient bulbs made up more than 70 per cent of sales, proving that the argument over lightbulb safety has moved on.

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And whilst LED lighting does emit a small amount of UV light, most scientists believe the levels are not high enough to cause significant skin damage, or cancer.

Still, the president promoted UV lighting this week as a potential coronavirus treatment, eight years after claiming that such lighting could cause cancer.

Months before his tirade against light bulbs, the president said in March 2019 that the noise emitted from wind turbines, or “windmills”, could cause cancer. Again, a claim that is not true.

“If you have a windmill anywhere near your house, congratulations, your house just went down 75 per cent in value. And they say the noise causes cancer,” Mr Trump told the National Republican Congressional Committee.

Mr Trump, a self-proclaimed ‘wind expert’, had told supporters in Michigan that "If it doesn't blow, you can forget about television for that night."

He added, mockingly: “‘Darling, I want to watch television.' 'I'm sorry! The wind isn't blowing.' I know a lot about wind."

Months later, Trump admitted that he “never understood wind” but did know “windmills very much”.

Describing “tremendous fumes”, which are not emitted by wind turbines, the president told young conservatives in December 2019 that “Gases are spewing into the atmosphere. You know we have a world, right? So the world is tiny compared to the universe. So tremendous, tremendous amount of fumes and everything.”

The president’s comments on fumes and gases – and the universe – were unclear, nor backed by scientific findings.