Re: RETAIL SCANNERS - RADIATION BURNS

["David Bromwich" <D.Bromwich@ens.gu.edu.au>]

Daamge from lasers is essentially thermal - causing tissue in 
structures such as the retina to heat.  If the rate of heating far 
excceds the rate of cooling, then the fluids in the tissue boil and a 
The retina can look a bit like a golf course with no obvious effects 
on sight unless the fovea is hit and the central vision is wiped 
out. 

The lasers in a POS outlet would be either Class 1 or Class 2.  In 
the case of Class 1, the amount of energy it delivers per square mm 
is too small to cause thermal damage.  Sit there staring till you die 
of boredom.  Class 2 may have suffienient energy, but you would have 
to deliberately stare into the beam.  On the positive side, 
supermarkets are usually well lit, so the pupil of the eye would be 
relatively small, giving a small target for the beam.  Also, the beam 
is usually scanning so that it can read barcodes, so the beam would 
sweep across the eye and little energy would be deposited.  This, and 
general broadeneing of a beam through the atmosphere readuces the 
risk from the much higher powered entertainment lasers.

Slips and falls are a far greater problem in shops.

Hope this is of help.

> Reply-to: Don.Mitchell@p0.f210.n244.z1.fidonet.org (Don Mitchell)

> 
> Has anyone heard of cashiers developing a radiation burn from scanners used in retail point of sales systems.
> 
> All replies will be appreciated.


David Bromwich, CIH 
Lecturer, Occupational Hygiene     tel (+617) 8757487
Faculty of Environmental Sciences  fax (+617) 8757459
Griffith University, Nathan Q 4111 AUSTRALIA