Phil Fox Rose

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August 13, 1990

The effects of VDT radiation

The video display terminal radiation issue has rocketed to the top of consumer attention lately, but most users and dealers know little about the issue other than that VDT emissions are bad.

But monitors emit several distinct types of radiation, and manufacturers may claim control of one type or one range within a type, while doing nothing in another.

Radiation from monitors can be divided into four main categories: visible light, X-rays, electric (static electricity) and electromagnetic. Since the 1960s most displays have shielded virtually all X-rays.

The modest hazards associated with static electricity have been understood for some time. These include skin and respiratory problems related to the attraction of large amounts of dust and the reduction of life-enhancing ionized air. While certainly important, these effects are not life threatening. Also, accessories have been available for years to drain off static electricity, usually with a grounded metal mesh placed over the screen.

What has people scared today is electromagnetic radiation. Monitors create these emissions as a side effect of their operation. They create magnetic fields to guide the electron beam that traces the image on the screen. Magnetic fields such as these have been suspected of causing a variety of ills including elevated cancer rates in children, abnormal pregnancies and miscarriages.

It is difficult, however, for computer monitor manufacturers and resellers to acknowledge the problem and offer solutions to their customers. By doing so, the immediately categorize the rest of the products they offer as cancer-causing horrors. Resellers have additional problems when offering add-on screen filters that block radiation. They sell the customer a particular monitor, then must say: "The product that I just sold you is no good — in fact, it is deadly — unless you buy this additional product."

The ice has been broken recently by a number of events. VDT emission concerns have gained mainstream publicity, thanks largely to a series of articles appearing in the New Yorker by Paul Brodeur in June 1989 and to an upcoming EPA report.

In July of this year, a collection of competing monitor manufacturers met in a highly publicized event to discuss the problem. Also last month, Sigma Designs Inc. was the first company to announce plans to offer its low-radiation model in the United States. A number of companies have been making these monitors for years to meet Sweden's VDT emission controls, but found little or no market in this country. Other makers are rushing in now that Sigma has taken the first step.

The current product that offers the most – though still incomplete – protection is the NoRad Shield from NoRad Corp., in Santa Monica, Calif.