“The wild cards in the VDT debate are the eleven clusters of problem pregnancies and miscarriages among women who work on or nearby VDTs,” says Louis Slesin, editor of Microwave News and publisher of the sister publication VDT News.[[45]] Some computer industry spokesmen and federal officials think the clusters show up by chance. Slesin, however, while noting that the “normal” miscarriage rate in the U.S. is almost 20 percent, says: “The incidence of birth defects is harder to account for.” And he says similar clusters haven’t popped up among women tapping away on typewriters.
These clusters—found in widely scattered offices in the U.S. and Canada—may result from causes other than radiation. Some VDT operators feel less in control of their jobs than do traditional typists; and a remote possibility exists that this additional stress could take its toll on the unborn children. Slesin says fear of VDTs may itself increase the stress—a Catch-22 if ever one existed.
Seeking a definitive answer on the birth-defect and miscarriage questions, NIOSH in 1984 was planning a study of about 5,000 pregnancies in a two-year period. Perhaps one-half of the women would use terminals. And the study would tell if they had more miscarriages and children with birth defects than did the other mothers. It would not pinpoint the cause, however—justification for further study.
A possible culprit here is very low frequency (VLF) radiation from the flyback transformer.
The transformer whips the cathode ray tube’s electron beams from one side to the other of the phosphor-coated screen, then back again. Typically a flyback transformer gives off radiation pulses at the rate of about 16,000 cycles a second, far below the AM radio broadcast band—hence, the term VLF. Could pulses at this frequency have biological effects?
We don’t know about VLF. But a Spanish scientist named Jose Delgado says even very weak pulses of extremely low-frequency radiation (ELF), the term for below 300 cycles a second, have damaged chick embryos. Some authorities question the “Delgado effect”; still, scientists in both the U.S. and Europe are undertaking similar experiments. Trying to gauge the possible risks from ELF, researchers may face certain technical complexities. Some scientists talk about “windows” of power and frequency. Just a slightly lower or higher frequency, for instance, might mean the difference between safety and danger for expectant mothers.
Like it or not, the jury is still out on the low frequency issue, and some companies may want to protect themselves legally—just in case—by transferring pregnant women from VDTs. Ideally you’d coordinate this policy with those regarding maternity leaves and other health benefits; then a woman would feel free to tell you immediately about her pregnancy instead of disguising it for as long as possible.
Even if radio frequency radiation is a culprit, there is some hope. Slesin notes that the flyback transformer is on the side or back of a computer monitor rather than in the front near the operator. That isn’t the best news for someone sitting near the flyback transformer of a coworker’s machine, but perhaps the VLF threat isn’t so great to someone without any other VDTs nearby. “With the right office layout,” says Mark Pinsky, editor of VDT News, “you might be able to greatly reduce exposure to VLFs fields. And obviously the risk to home computer users might be less without another machine around.”
Although VDTs have yet to be proven free of radiation risks, please note that groups like 9 to 5 and the Newspaper Guild have been using at least a few computers in their offices for several years. Don’t lie to your people that there’s nothing to worry about; do point out that the risks are low enough to justify computerization’s benefits.
“Can computer screens cause cataracts?” some employees might also ask.