This week, the US government delayed a ban on three hazardous chemicals known to be dangerous and even lethal to human beings, postponing them for "long term action" while simultaneously shelving plans for hundreds of other regulations.

While that may seem shocking, scientists say this failure of oversight when it comes to protecting the public from dangerous chemicals is nothing new. In fact, new research says we've all been exposed to tens of thousands of virtually untested chemicals for decades now, about which we know little or even nothing.

"If a chemical is found to present a danger to health or the environment, appropriate regulatory action can be taken before it is too late to undo the damage," President Gerald Ford said as he signed the United States Toxic Substances Control Act (TSCA) in 1976.

Firm, sensible words. But according to a new editorial in PLOS Biology – part of a special series of papers examining the mismanagement of chemical regulations in the US since the 1950s – none of that oversight actually occurred.

At the time of the 1976 signing, some 60,000 or more chemicals were already in use in things like manufacturing, agriculture, and heavy industry.

That chemical head count now stands at somewhere north of 85,000, but the 60,000 existing chemicals were never properly scientifically vetted, the researchers say. Instead, they were simply "grandfathered into the law on the assumption that they were safe".

Worse still, after years of legal and political pressure on the Environment Protection Authority (EPA) in the decades since, the majority of the 25,000 new chemicals also didn't undergo significant safety testing prior to their approval for commercial use.

Maybe that shouldn't be so surprising.

After all, modern toxicology research is continually finding hazardous chemicals turning up in everything from our drinking water to common packaging materials, and the effects of exposure can be far-reaching.

"Hazardous chemicals enter the environment from the factories where they're made and added to a dizzying array of consumer products – including mattresses, computers, cookware, and plastic baby cups to name a few – and from landfills overflowing with our cast-offs," the researchers explain.

"They drift into homes from nearby agricultural fields and taint our drinking water and food. Today, hundreds of industrial chemicals contaminate the blood and urine of nearly every person tested, in the US and beyond."

In five separate case studies, the researchers look at the problem from different perspectives, including the effects of chemical exposure on children's health and the historical failures of the TSCA.

One of the papers looks at a surprising phenomenon that may have been completely missed by health authorities: sometimes lower doses or levels of exposure to toxic chemicals are actually more dangerous than higher amounts.

The studies come at what could be a pivotal time in public health, given the Trump administration's seeming obsession with cutting regulations and 'red tape'.

As one of the researchers, PLOS Biology senior editor Liza Gross, explains in a blog post, within two weeks of taking office, President Trump had ordered government agencies to rescind two regulations for every new rule, ostensibly for cost-cutting purposes.

In some areas this kind of 'regulation trading' could conceivably save money, but for an organisation like the EPA – whose regulations are supposed to protect public health – some say it's an impossible rule to follow, and led to one EPA official with 30 years of experience resigning in protest.

"This poses a real Sophie's choice for public health agencies like EPA. Should EPA repeal two existing rules protecting infants from neurotoxins in order to promulgate a new rule protecting adults from a newly discovered liver toxin?" the official stated in a public sign-off.

"Faced with such painful choices, the best possible outcome for the American people would be regulatory paralysis where no new rules are released so that existing protections remain in place."

When it comes to how dangerous chemicals are regulated in the US, it seems there are no easy answers right now, but the researchers say, if there's to be a safer future for all of us, it can't just be left to the science community to figure out.

"[S]cience is not always enough," the team explains.

"Closing the gap between evidence and policy will require that engaged citizens, both scientists and nonscientists, work to ensure our government officials pass health-protective policies based on the best available scientific evidence."

The research is published in a series of articles in PLOS Biology.