# Excessive x-rays in pre-1968 TVs **URL:** \ **Category:** Factual Questions\ **Created:** [April 30, 2002, 12:07am UTC](https://boards.straightdope.com/t/excessive-x-rays-in-pre-1968-tvs/106382 "2002-04-30T00:07:36Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![jiHymas](https://avatars.discourse-cdn.com/v4/letter/j/439d5e/32.png) [@jiHymas](https://boards.straightdope.com/u/jiHymas)\ **Post date:** [April 30, 2002, 12:07am UTC](https://boards.straightdope.com/t/excessive-x-rays-in-pre-1968-tvs/106382/1 "2002-04-30T00:07:36Z")
The master makes the comment that “Prior to 1968 or so some [TV] sets emitted excessive X-rays, but that problem has now been eliminated.” ([http://www.straightdope.com/classics/a920724.html](http://www.straightdope.com/classics/a920724.html), repeated as [http://www.straightdope.com/classics/a5\_105.html](http://www.straightdope.com/classics/a5_105.html)). What does “some” mean? What does “excessive” mean? How would an hour’s TV watching compare in exposure to, say, a dental x-ray? ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [April 30, 2002, 12:37am UTC](https://boards.straightdope.com/t/excessive-x-rays-in-pre-1968-tvs/106382/2 "2002-04-30T00:37:35Z")
> [@](#): > > When the TV x-ray problem first became a public concern in 1966, the Surgeon General recommended that viewers sit at least six feet from an operating receiver to reduce the **quite low potential** of biological damage. Bolding is mine. From [http://www.fda.gov/cdrh/consumer/TVRad.html](http://www.fda.gov/cdrh/consumer/TVRad.html) So I doubt that it was significant, but this will get things started. ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [April 30, 2002, 12:43am UTC](https://boards.straightdope.com/t/excessive-x-rays-in-pre-1968-tvs/106382/3 "2002-04-30T00:43:01Z")
> [@](#): > > When the TV x-ray problem first became a public concern in 1966, the Surgeon General recommended that viewers sit at least six feet from an operating receiver to reduce the **quite low potential** of biological damage. Bolding is mine. From [http://www.fda.gov/cdrh/consumer/TVRad.html](http://www.fda.gov/cdrh/consumer/TVRad.html) So I doubt that it was significant, but this will get things started. ---
**Author:** ![jiHymas](https://avatars.discourse-cdn.com/v4/letter/j/439d5e/32.png) [@jiHymas](https://boards.straightdope.com/u/jiHymas)\ **Post date:** [April 30, 2002, 1:41am UTC](https://boards.straightdope.com/t/excessive-x-rays-in-pre-1968-tvs/106382/4 "2002-04-30T01:41:49Z")
> [@](#): > > _[http://www.cco.caltech.edu/~safety/trm.html#A4](http://www.cco.caltech.edu/~safety/trm.html#A4)_ > \*\*Caltech’s whole body dose limit for planned exposures is 500 mrem/year (5 mSv/yr). If a Caltech worker were to receive the maximum allowable planned dose each year for twenty years, the total dose received would be 10 rem (0.1 Sv). According to the BEIR V report, the worker’s chance of death from cancer would increase by approximately 0.4%. This is fairly small compared to the normal chance of death from cancer in the U. S. of about 20%. > \*\*_Note: for x-rays, 1 Rem = 1 Roentgen, ibid._ > [@](#): > > _[http://www.ccnr.org/radiation\_standards.html](http://www.ccnr.org/radiation_standards.html)_\*\* > With one more important piece of information, namely that medical X-ray is measured by the mR in air at skin entrance (rather than by tissue or bone marrow dose as used by the physicist), I will telescope some ten years of research into a few short conclusions: > > For X-ray of arms or legs, and dental X-ray, it requires an accumulated dose of 4000 mR to increase the risk of non-lymphatic leukemia the same amount as one year of natural aging. > > For chest X-ray, it requires an accumulated dose of 1670 mR at skin entrance to simulate one year’s natural aging for increasing non-lymphatic leukemia rate. \*\* The source provided by samclem ([http://www.fda.gov/cdrh/consumer/TVRad.html](http://www.fda.gov/cdrh/consumer/TVRad.html)) states that the current standard (mandatory in the US from June 1, 1971) was 0.5 milliRoentgen/hour; but it doesn’t state how far away from the set this is measured (important due to inverse-square law) or what the situation was prior to 1968. But we’re on the right track.