The US government is attempting to rein in the activities of pseudoscience groups that have begun to peddle bleach solution as a “miracle cure” for coronavirus.

The US Food and Drug Administration (FDA) has taken rare action against a leading supplier of the supposed remedy, a group that goes by the name of Genesis II Church and operates out of Florida.

A federal court last week issued a temporary injunction, ordering the group to stop selling “an unproven and potentially harmful treatment for Covid-19”.

Despite the clampdown, the Guardian has learned other groups have begun to repackage bleach, which had been touted as a cure for autism and cancer, as a foolproof treatment for coronavirus.

A closed membership group on Facebook run by a purported “chemist” in Grove City, Ohio, is also billing the bleach, known by its advocates as MMS, as a “cure” for Covid-19.

Advocates of the pseudo-medicine adhere to a similar formula. Sodium chlorite and citric acid are combined to form MMS, or “miracle mineral solution”, which they fraudulently claim cures 95% of all known illnesses including cancer, Aids/HIV and malaria.

In fact, when the two components are combined they produce chlorine dioxide, a powerful bleach normally used in industrial processes such as the manufacture of textiles.

Last August the FDA issued an urgent warning, urging Americans not to buy or drink the product, which it said was a “dangerous bleach which has caused serious and potentially life-threatening side effects”. Drinking MMS can cause nausea, diarrhea and severe dehydration that can lead to death, the federal agency said.

The Guardian has learned that Gregorio Placeres is running a secretive Facebook group called SCSINFO-AUTISM out of his Ohio home. The group, which has almost 17,000 members, can only be accessed with the approval of administrators of the site.

Once inside the group, members are encouraged to drink a mix of six drops of sodium chlorite with 60ml of water. Children should take a similar dose, the group says.

Anyone who contracts Covid-19 should double the dose by drinking it twice a day, it says.

“Two takes a day until the syntoms cess for full [sic]”, the site says.

A notice cautions new members that the bleach can induce “an oxidative crisis. This can be diarrhea or vomiting”.

The notice goes on to state that in normal circumstances users would be advised to desist drinking the chemical after an adverse reaction. “But in case you are infected with Covid-19, you can continue with your shots.”

The Guardian reached out to Placeres. He stood by the claim pushed in his Facebook group that the bleach can cure Covid-19, but denied that he sold any of the chemicals.

“I just help people by telling them how to use it,” he said.

Asked for his response to the US government advice that the bleach is potentially life-threatening, he replied: “The FDA has a financial interest in this problem because it’s run by people in the pharmaceutical industry.”

Fiona O’Leary, a campaigner against pseudoscience whose work helped to get MMS banned in Ireland in 2016, said the FDA move against Genesis II was “long overdue. I’m delighted, and I hope it leads to a real prosecution. We need to see this in a criminal frame, the warnings alone don’t work.”

The Genesis II group sells bleach product as MMS in Bradenton, Florida, where a makeshift factory has been set up in the backyard of Jonathan Grenon. He styles himself as a “bishop” of the church which was founded by his father, “Archbishop” Mark Grenon.

The Guardian last year exposed how Genesis II openly peddled bleach at public meetings in Washington and New York states.

Last May the Guardian revealed that a Briton named Sam Little had helped to fund a network that was distributing MMS as a “cure” for malaria and cancer to 50,000 villagers in Uganda. He was arrested and jailed, though later released.