Nuke Expert Dana Durnford Unpacks – Linear No-Threshold (LNT) Debate
Trump’s EPA moving to loosen radiation limits, Financial Post, Ellen Knickmeyer, 2 Oct 18 WASHINGTON — The Trump administration is quietly moving to weaken U.S. radiation regulations, turning to scientific outliers who argue that a bit of radiation damage is actually good for you — like a little bit of sunlight.
The government’s current, decades-old guidance says that any exposure to harmful radiation is a cancer risk. And critics say the proposed change could lead to higher levels of exposure for workers at nuclear installations and oil and gas drilling sites, medical workers doing X-rays and CT scans, people living next to Superfund sites and any members of the public who one day might find themselves exposed to a radiation release.
The Trump administration already has targeted a range of other regulations on toxins and pollutants, including coal power plant emissions and car exhaust, that it sees as costly and burdensome for businesses. Supporters of the EPA’s new radiation guidance argue the government’s current no-tolerance rule for radiation damage forces unnecessary spending for handling exposure in accidents, at nuclear plants, in medical centres and at other sites.
…… The proposed rule would require regulators to consider “various threshold models across the exposure range” when it comes to dangerous substances.
While it does not specify that it’s addressing radiation and chemicals, an EPA news release on the rule quotes Edward Calabrese as saying it would: “The proposal represents a major scientific step forward by recognizing the widespread occurrence of non-linear dose responses in toxicology and epidemiology for chemicals and radiation and the need to incorporate such data in the risk assessment process.”
The comment period for the science regulation has ended and the agency is currently reviewing the comments. There’s no specific date for final action by the administration. The EPA declined to make an official with its radiation-protection program available.
… what’s of concern is the higher-energy, shorter-wave radiation, like X-rays, that can penetrate and disrupt living cells, sometimes causing cancer.
As recently as this March, the EPA’s online guidelines for radiation effects advised: “Current science suggests there is some cancer risk from any exposure to radiation.”
“Even exposures below 100 millisieverts” — an amount roughly equivalent to 25 chest X-rays or about 14 CT chest scans — “slightly increase the risk of getting cancer in the future,” the agency’s guidance said.
But that online guidance — separate from the rule-change proposal — was edited in July to add a section emphasizing the low individual odds of cancer: “According to radiation safety experts, radiation exposures of …100 millisieverts usually result in no harmful health effects, because radiation below these levels is a minor contributor to our overall cancer risk,” the revised policy says.
…….. The radiation regulation is supported by Steven Milloy, a Trump transition team member for the EPA who is known for challenging widely accepted ideas about manmade climate change and the health risks of tobacco. He has been promoting Calabrese’s theory of healthy radiation on his blog.
But Jan Beyea, a physicist whose work includes research with the National Academies of Science on the 2011 Fukushima nuclear power plant accident, said the EPA science proposal represents voices “generally dismissed by the great bulk of scientists.”
The EPA proposal would lead to “increases in chemical and radiation exposures in the workplace, home and outdoor environment, including the vicinity of Superfund sites,” Beyea wrote.
At the level the EPA website talks about, any one person’s risk of cancer from radiation exposure is perhaps 1 per cent, Beyea said.
“The individual risk will likely be low, but not the cumulative social risk,” Beyea said.
“If they even look at that — no, no, no,” said Terrie Barrie, a resident of Craig, Colorado, and an advocate for her husband and other workers at the now-closed Rocky Flats nuclear-weapons plant, where the U.S. government is compensating certain cancer victims regardless of their history of exposure.
“There’s no reason not to protect people as much as possible,” said Barrie.
U.S. agencies for decades have followed a policy that there is no threshold of radiation exposure that is risk-free.
The National Council on Radiation Protection and Measurements reaffirmed that principle this year after a review of 29 public health studies on cancer rates among people exposed to low-dose radiation, via the U.S. atomic bombing of Japan in World War II, leak-prone Soviet nuclear installations, medical treatments and other sources.
Twenty of the 29 studies directly support the principle that even low-dose exposures cause a significant increase in cancer rates, said Roy Shore, chief of research at the Radiation Effects Research Foundation, a joint project of the United States and Japan. Scientists found most of the other studies were inconclusive and decided one was flawed.
None supported the theory there is some safe threshold for radiation, said Shore, who chaired the review.
If there were a threshold that it’s safe to go below, “those who profess that would have to come up with some data,” Shore said in an interview.
“Certainly the evidence did not point that way,” he said……… https://business.financialpost.com/pmn/business-pmn/epa-says-a-little-radiation-may-be-healthy