How to evaluate hazards in using bar code scanners in chemical manufacturing

I was recently asked about hazards of using bar code scanners in chemical manufacturing sites.
Aside from the bar code’s laser damage to eyes, there may be a concern about the electronic equipment in volatile areas.
When I am asked not to bring a cell phone or tablet computer into industrial areas, the concern is usually about volatile gases or vapors. Different classifications exist, and their identification can help determine the controls needed.
A paper titled Zone Hazardous Location discusses identification of, and addressing ignition risk where vapors or solids (dust) are present. I am not affiliated with Allen-Bradley.
Testing is also discussed in this list of web sites. I am not qualified to recommend specific testing methods, equipment or suppliers. Safety engineering specialists among your nearby university’s faculty may be a better source for such advice.
One example for intrinsically safe devices is discussed here. I am not affiliated with Barcoding, Inc.
I hope this helps!