Editor’s Note: This week, the Food and Drug Administration sent us a letter, which we have posted below, taking issue with several passages in our story about airport body scanners. The letter generally takes semantic issue with how we presented specific facts. It does not, in our judgment, raise any issues of substance.

For example, a section heading in our story stated that there has been little research on the cancer risks of body scanners. The FDA asserts that studies of radiation risk in general should be accepted as applying to the radiation generated by the scanners.

More broadly, the FDA takes issue with how we conveyed the cancer risk from the scanners. The agency says the amount of radiation the scanners emit is “extremely small.” We call it “extremely low.” The agency says the risk of fatal cancer is 1 in 400 million – an estimate it did not provide to ProPublica before publication – and cites the National Council on Radiation Protection and Measurements (NCRP) to say that estimating cancer cases from low levels of radiation produces “a distorted image of risk.” We cited two peer-reviewed research papers by prominent academics – including one who served on the NCRP panel that examined body scanners – that estimated six or 100 additional cases of cancer over a lifetime could be caused among the 100 million passengers who fly each year. (Those passengers were estimated to take 750 million or one billion flights.) To put this risk in context, we noted that “the same 100 million people would develop 40 million cancers over the course of their lifetimes.”

Separately, the agency asserts that we erred in stating, “The FDA does not review or approve the safety of such products.” But the agency omits our next sentence: “However, manufacturers must provide a brief radiation safety report explaining the dose and notify the agency if any overexposure is discovered.” That sentence is important, because the FDA letter itself states that “a manufacturer of an x-ray security screening product can legally sell a product after they submit the required radiation safety report. Federal law does not include authority for an approval process for the radiation safety of electronic products.”

In another case, the FDA objects to this sentence: “Instead, the FDA decided to go with a voluntary standard set by a trade group largely comprising manufacturers and government agencies that wanted to use the machines.” The agency says that “FDA chose to initiate a balanced consensus standard development process…” But the “consensus standard” is not mandatory. A company could produce a scanner that exceeds it, and the burden would be on the FDA to show the radiation emitted by such a scanner is unreasonable. Also, in explaining the process of how the standards were set, we believe the FDA does not contradict the essence of our reporting: The task of setting the standard was handled by a non-profit group that sets standards for many industries, the American National Standards Institute. ANSI, in turn, relied on what the FDA acknowledges was the “working group which wrote the standard.” As we reported, that working group, which we termed a committee, “was made up of 15 people, including six representatives from manufacturers of X-ray body scanners and five from U.S. Customs and the California prison system. There were few government regulators and no independent scientists.”

ProPublica takes seriously our responsibility to correct mistakes and clarify misstatements. But while the FDA may prefer different terminology, we believe the way we conveyed the facts was accurate.

Paul Steiger, Editor-in-Chief and CEO

The FDA’s Response

FDA spokesperson Erica V. Jefferson emailed ProPublica the following response for publication.

ProPublica article Nov 1, 2011 – clarifications

For further information and references regarding these topics please visit the FDA web page on products for security screening of people - http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/SecuritySystems/ucm227201.htm

For an overview of FDA’s regulatory authorities over manufactures of electronic products please see the FDA Basics page regarding radiation emitting products: http://www.fda.gov/AboutFDA/Transparency/Basics/ucm193809.htm

  • “Little research on cancer risk of body scanners.”

    The risks from the x-ray body scanners are from the dose of x radiation delivered during a scan. The risks from a dose of x radiation (a form of ionizing radiation) has been studied and documented. The effective dose of x radiation delivered to an individual being screened has been verified multiple times by multiple organizations. Thus the incremental increase in cancer risk can be calculated and is extremely small. The dose is so small that it is only a fraction of what is defined as a negligible dose. A strict interpretation of the linear-no-threshold radiation dose to risk relationship indicates for the systems in use by TSA there is an incremental increase in the risk of a fatal cancer of 1 in 400,000,000. The x-ray spectrums emitted by these products are not significantly different from x-ray spectrums used for medical imaging; therefore, studies on x-ray dose from medical imaging are relevant to the dose from a scanner. There have been statements made about very soft x-rays from these products – those statements are not correct, there is at least 1 mm of aluminum equivalent used which eliminates soft x-rays from the spectrum.

    Note: An increase in risk of 1 in 400,000,000 means an individual’s theoretical risk is theoretically raised by this minute amount. It does not mean one screening out of every 400,000,000 screenings will result in a death. The National Council on Radiation Protection and Measurements (NCRP) has said: “The summation of trivial average risks over very large populations or time periods into a single value produces a distorted image of risk, completely out of perspective with risks accepted every day, both voluntarily and involuntarily.” This quote is from NCRP Report No. 121 (1995), Principles and Application of Collective Dose in Radiation Protection.

  • “Although they deliberately expose humans to radiation, the airport X-ray scanners are not medical devices, so they are not subject to the stringent regulations required for diagnostic X-ray machines.”

    FDA has regulatory authority over the manufacturers of electronic products which emit (or could emit) radiation under the Electronic Product Radiation Control (EPRC) provisions of the Federal Food, Drug, and Cosmetic (FFDCA) act. Every x-ray product is an electronic product and some x-ray products are also medical devices. Manufacturers of medical x-ray products are subject to both medical device and EPRC requirements. Manufacturers of medical diagnostic x-ray products are in addition to general requirements required to assure their products meet the requirements of a specific mandatory performance standard under EPRC regulations.

    FDA continues to use the regulatory tools available under the EPRC authorities of the FFDCA to protect the public health and safety from electronic product radiation. Manufacturers of x-ray products are required to provide details of the radiation emission and radiation safety characteristics of their products to FDA prior to selling those products. FDA has authority to inspect electronic product manufacturers for good cause. The EPRC provisions allow FDA to order manufacturers to take a corrective action (repair, repurchase, or replace) if their electronic products are ever discovered to have a radiation safety defect which was caused by the product’s design, manufacturing, or assembly. FDA also has approval authority over a manufacturer’s corrective action plan and can order further action if a manufacturer’s initial corrective action is not adequate. Manufacturers are required to cover all costs associated with corrective actions.

    Note: The law does not include authority for an approval process for the radiation safety of electronic products. Please see our website for legal and regulatory details.

  • “The FDA does not review or approve the safety of such products.”

    FDA does review the radiation safety characteristics of electronic products. FDA can require submission of additional information until we are either satisfied there is not a significant risk to public health and safety or verify there is a problem. However, a manufacturer of an x-ray security screening product can legally sell a product after they submit the required radiation safety report. Federal law does not include authority for an approval process for the radiation safety of electronic products.

  • “Instead, the FDA decided to go with a voluntary standard set by a trade group largely comprising manufacturers and government agencies that wanted to use the machines.”

    FDA chose to initiate a balanced consensus standard development process following the requirements of the appropriate accredited standards committee (ASC). A consensus radiation safety standard provides a reference for the best practices regarding particular products. Additionally, a consensus standard is not limited to product performance requirements (FDA’s mandatory standards are restricted to product performance requirements) – it can include user requirements as well. ANSI manages the accreditation of standards committees to assure the standard approval process is equitable to all parties. ANSI did not write the consensus standard for people screening products. The working group which wrote the standard was chaired or co-chaired by FDA staff. The ASC approved the chair of working group and has to approve a draft standard for the standard to be published. Neither the ASC nor the working group was dominated by manufacturers or users. There were no representatives of people screening product manufacturers on the ASC. In this case the appropriate ASC is designated N43 Equipment for Non-Medical Radiation Applications. TheN43 ASC is administered by the Health Physics Society (a professional society for people working in the radiation safety area (health physicists)). The N43 committee determined the standard (both versions) was acceptable and approved it. N43 members are all experienced radiation safety professionals.