"Reference Man" May Lose Radiation Modeling Job
By Julie R. Enszer
Tuesday 13 November 2007
Safe levels of ionizing radiation from products such as smoke detectors and mammograms are based on a male health subject. Health advocates want statistics based more on fetuses, girls and women to take over as the model.
The "reference man" is a statistical model. He dates to 1974, but he's perpetually aged between 20 and 30 years old. He weighs 170 pounds, stands 5 feet 7 inches and hails from Western Europe or North America.
And he represents everyone in the United States when it comes to setting regulations for acceptable standards of exposure to ionizing radiation.
But if the Institute for Energy and Environmental Research and other advocates get their way, he will step aside and let women and children - who are more vulnerable to radiation's medical effects - take over the job.
"We believe the government has an obligation to protect more than just adult white men from the hazards of radiation," says Lisa Ledwidge, outreach director at the institute. "Until these standards are changed, the government is not fulfilling its responsibility."
A June 2005 report from the Washington-based National Research Council finds women 52 percent more likely to develop some form of cancer than men following uniform whole-body exposure to the same level of radiation.
Children and fetuses are the most vulnerable to developing cancer due to radiation exposure. This is because they have a longer life expectancy and the intensive cell replication for physical growth. Children and fetuses are also more vulnerable to neurological damage and genetic mutations that affect growth and development.
Because of the U.S. Environmental Protection Agency's use of the "reference man" as a health model, the Institute for Energy and Environmental Research's principal scientist and president, Arjun Makhijani, advised an EPA regulatory committee last summer that the agency "averages male and female risks in its regulatory practice in a way that is entirely inappropriate."
Makhijani also criticized the EPA committee's draft review of guidelines released in July 2007, for failing to discuss sex-specific overall risk factors of exposure to radiation, except in regards to lung cancer in women. He also criticized the review for not giving girls special consideration, "since females are at greater risk when they are young as well."
Immediate Focus on EPA
Ledwidge says the immediate focus is getting the EPA, the chief agency in charge of regulating radiation standards, to lower current limits.
But the coalition of groups and individuals behind the Institute for Energy and Environmental Research-led "Healthy From the Start" campaign want reform throughout the government.
Ledwidge says the Department of Energy, the Nuclear Regulatory Commission and the Occupational Safety and Health Administration all use standards based on the "reference man" or some similar model.
Campaigners want the EPA to change the reference man to a "hypothetical maximum exposed individual," based on a model that better represents those most vulnerable to ionizing radiation, such as a pregnant woman or girl.
This would mean lowering workplace exposure levels to 2 rems per year from 5 rems. But a much smaller exposure - 100 millirems - is considered the safe threshold for fetuses, which is why pregnant women are generally advised to avoid X-rays, including dental scans.
Rem stands for Roentgen Equivalent Man and is named after the German physicist who discovered X-rays; a millirem is one one-thousandth of a rem.
More drastic cuts are called for radiation workers who declare a pregnancy. Currently, women with a declared pregnancy working at jobs with radiation exposure can legally be exposed to 500 millirems. Campaigners want that lowered to 100 millirems.
According to Makhijani, the economic implications of this policy change "are not huge. For pregnant women, the policy usually is to not allocate them work in radiation areas, unless they ask to remain in such areas, so the de facto goal often is zero additional dose. In addition, most worker exposures are now below 2 rem."
Where it may make a difference is in repair and maintenance in highly radioactive areas, such as working with fuel supplies at nuclear power plants, he says, since a change in the standards for exposure would benefit worker health and safety.
Advocates hope the EPA's radiation advisory committee will release new recommendations by the end of 2007. The EPA said the report will be made public as soon as it is completed.
No Safe Amount
Makhijani's July testimony to the radiation advisory committee of the EPA's scientific advisory board highlighted a 2005 report by the National Research Council of the National Academies finding "a linear, no-threshold dose-response relationship between exposure to ionizing radiation and the development of cancer in humans."
In other words, there is no safe amount of ionizing radiation, and it has a direct link to cancer development.
Ionizing radiation - often simply called radiation - comes from unstable atoms emitting invisible energy waves or particles. It has natural environmental sources - such as the sun - and also comes from human-made products such as smoke detectors, dental crowns, some watches and clocks, and medical and dental X-rays including mammograms.
Increasingly, environmental exposure - including tritium in water from nuclear power plants and clean-up of nuclear weapons facilities - is a concern. Switching from the reference man could mean regulators limit the amount of radiation that can be discharged from nuclear weapons facilities and nuclear power plants, a goal of activists for people who live downstream or downwind from these locations.
The Institute for Energy and Environmental Research, a nonprofit group founded in 1987 and based in Takoma Park, Md., produces scientific reports for the general public designed to influence policymaking. Their reports have influenced U.S. ozone layer depletion policies and regulations regarding the environmental and human impact of nuclear weapons manufacturing. The institute uses scientists to review research but also includes people who are directly affected by the science in their process of reviewing scientific papers and policies.
Everyone is exposed to some radiation each year during daily activities. Radiation can damage living cells and the DNA in cells; excessive doses can have deleterious, long-term health consequences, including cancer and birth defects.
A coalition of organizations and individuals are in the Healthy From the Start campaign, including the American Public Health Association, based in Washington, D.C.; Women's Action for New Directions, Arlington, Mass.; and Making Our Milk Safe, or MOMS, Alameda, Calif. Together, these organizations and others are circulating a petition to President Bush asking him to change the regulations throughout the federal government.
This is the first step in what organizers see as a long-term campaign to change radiation exposure guidelines to protect the most vulnerable.
The reference man - as a model for radiation protection - was first created by the International Commission on Radiological Protection in 1974 and was used in 1988 by the EPA to set current regulations for radiation exposure. Regulation of radiation exposure dates to the early 1930s; after the development of the atomic bomb in the 1940s and 1950s, the regulatory focus was on the safety of atomic workers.
As scientists and policy-makers have learned more about the dangers of radiation and particularly its link to cancer and birth defects, regulations have tightened.
If the Healthy From the Start campaign achieves tighter restrictions, Mary Brune, co-founder and director of MOMS, says that will be an overall boon for public health.
"If we can create policies protective of pregnant women and the babies they carry - as well as nursing mothers - then the world will be safe for everyone."
For More Information:
Institute for Energy and Environmental Research, Healthy From the Start Campaign:
US Environmental Protection Agency:
Calculate Your Radiation Dose: