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The Committee to Minimize Toxic Waste (CMTW) has put forth a new teaching on tritium, a radioactive isotope of hydrogen. Before examining this new teaching, let me remind you that the CMTW preaches that tritium is the “baddest” of all radioactive substances and that the “evil” Department of Energy (DOE) has endangered the good citizens of Berkeley by locating a scientific laboratory that uses it in a “dangerous” earthquake and firestorm area. Although the tritium at Berkeley Lab is stored in the inert form of uranium tritide, this is never mentioned in the CMTW’s teachings. Furthermore, they suppress the fact that tens of thousands of curies of tritium are also stored in fragile glass tubes in public and private buildings throughout Berkeley. 

So how do the disciples of the CMTW justify this teaching that tritium is dangerous in the Hills, but not in the Flatlands? Could it have anything to do with the fact that both the CMTW co-chairs live in the Hills? Ms. Gene Bernardi (Perspective, May 11) squares this circle by preaching that Berkeley Lab is releasing tritiated water vapor which is “bad” tritium whereas the tritium in Exit signs is in the form of hydrogen gas and is “good” tritium. 

In putting forth CMTW’s new teaching, Ms Bernardi distorts the truth by not telling the public that the tritium released from both the Berkeley Lab and stored in EXIT signs consist of mixtures of both chemical forms. In 1999, Berkeley Lab released tritium, which was 70 percent and 30 percent in the water vapor and hydrogen forms, respectively. For a six -year-old EXIT sign, the fraction of tritium in these two chemical forms is typically 10 percent and 90 percent. Thus, the ratio of “bad” tritium released from Berkeley Lab to the “bad” tritium in EXIT signs is about a factor of 10 and hardly the tens of thousands trumpeted by Ms Bernardi. Furthermore, hydrogen in the gas form is readily converted to water vapor, sometimes explosively as in the Hindenburg blimp disaster. Finally the Environmental Protection Agency (EPA) maintains that all tritium in the hydrogen form is converted to tritiated water vapor in the atmosphere. For this reason, the EPA uses the biological effectiveness of tritiated water vapor for both chemical forms when estimating radiation exposures to the public. 

So how dangerous are tritium releases from the Berkeley Lab? In 1999, 30 curies of tritium or 3 EXIT signs worth were released. If all of this tritium were breathed by a single individual, he/she would receive a sizable radiation dose. What Ms. Bernardi neglects to tell you is that the released tritium is diluted by over a trillion times. As a result, the maximum dose a person at the Lawrence Hall Science (LHS) would be exposed to is over a thousand times smaller than the dose from environmental sources and a hundred times below the regulatory limit. Even to get this small dose, a visitor to the LHS must live there for 24 hours a day for a year. Clearly visiting school children who spend only a small fraction of year at the LHS are not at risk. Furthermore, the EPA has verified these dose estimates by directly measuring the airborne tritium concentrations at the LHS. 

Ms. Bernardi implies that if a tritium-filled EXIT sign were to break in a schoolroom, it is not a cause for concern. Since a tritium-filled EXIT sign contains about 10 curies of tritium and a typical school room has a volume of about 100 m3, it is very easy to calculate the concentration that school children would be exposed to if a sign broke and released all of its tritium. Since 10 curies corresponds to 10,000,000,000,000 picocuries, by dividing the number of picocuries in the sign by the volume of the room, one obtains a tritium concentration of 100,000,000,000 picocuries/m3. Since the tritium concentration in a classroom from a broken EXIT sign would exceed those measured at the LHS by over a factor of a million, why is Ms. Bernardi not interested in these potential tritium exposures? Should not the CMTW be asking the EPA to declare all school buildings with tritium EXIT signs potential Superfund sites? Could it be that the CMTW is not interested in public health risks, but only in harassing the DOE? 

The proper way to evaluate the relative risks of tritium emissions from Berkeley Lab versus those from a broken EXIT sign would be to compare the respective radiation doses to a maximally exposed individual. In 1999 the highest potential offsite dose from Berkeley Lab air emissions was 0.1 mrem. An EXIT sign manufacturer estimates that the potential dose to an individual in a room with a broken EXIT sign would be 100 mrem, which is 1,000 times larger. Since the potential dose from a broken EXIT sign is a thousand times larger than that resulting from a field trip to the LHS, why is Ms. Bernardi not concerned about tritium that is actually in the classroom? 

With apologies to Leon Trotsky, “Everyone has the right to be wrong, but Ms. Bernardi abuses the privilege.” Perhaps, the CMTW should be called the Committee to Minimize Truth and Wisdom? For more on the CMTW Tritium Cover-up, stay tuned for a guide to the Tritium Hotspots in District 4. 

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Gordon Wozniak, Ph.D., is senior scientist at Lawrence Berkeley National Laboratory, and vice chair of the City of Berkeley’s Community Environmental Advisory Commission.