thanks, guys!

yea you most likely need an EX rated machine for dust related fire hazards
i remembered EX is explosion proof not EE (derrr)
glad to see you beat me to it joseph :)

air flight:

If your facility atmosphere has the potential for hazardous concentrations of activated carbon, you may need an EX rated forklift.

A review of several Material Safety Data Sheets (MSDS's) for Activated Carbon indicates that the material is explosive under certain concentrations with air. Synonyms include: Activated Charcoal, Activated Powder, Activated Coal.

The following statement comes from the J.T. Baker Chemical Company MSDS for Carbon, Activated, Powder: "5. Fire Fighting Measures, Fire: As with most organic solids, fire is possible at elevated temperatures or by contact with an ignition source. Activated carbon is difficult to ignite and tends to burn slowly (smolder) without producing smoke or flame. Wet activated carbon depletes oxygen from the air. Materials allowed to smolder for long periods in enclosed spaces, may produce amounts of carbon monoxide which may reach the lower explosive limit for carbon monoxide of 12.5% in air. Contact with strong oxidizers such as ozone or liquid oxygen may cause rapid combustion. Explosion: Fine dust dispersed in air in sufficient concentrations, and in the presence of an ignition source is a potential dust explosion hazard. Minimum explosible concentration 0.140 g/l. Fire Extinguishing Media: Water spray, dry chemical, alcohol foam, or carbon dioxide. Special Information: In the event of a fire, wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode."

US OSHA requires forklifts used in atmospheres containing hazardous concentrations of carbon black, coal or coke dust to be EX rated. Activated Carbon may fall into this category.

"US OSHA 1910.178(c)(2)(ii)(a): Power-operated industrial trucks shall not be used in atmospheres containing hazardous concentrations of metal dust, including aluminum, magnesium, and their commercial alloys, other metals of similarly hazardous characteristics, or in atmospheres containing carbon black, coal or coke dust except approved power-operated industrial trucks designated as EX may be used in such atmospheres."

I recommend you contact your property/casualty insurer and request a field engineer to review your facility to help you determine your forklift classification needs and methods to control dust exposure.

I also recommend you obtain and review the activated carbon material safety data sheets from each product manufacturer that you use.

Explosivity is not the only hazard posed by activated carbon. Your "very dusty environment" also poses respiratory and cardiovascular health hazards as the msds's will indicate. Both issues need to be addressed.

I feel that air_flight requires an EE rated machine. Recommend contact local dearers and give them the specs on what you require. Most EE rated electrics should be OK in this enviroment. Note: due to cooling problems EE rated machines cannot work as hard as non EE rated, also require short P.M. interviles to blow out dust.

i see what hes asking
i believe he manufactures activated carbon for products like respirator filters, fish tank filters, etc
there is quite a bit of dust involved in the process

so the question thats most important:
is there a flash fire hazard from airborne dust ?
i would imagine you would want a refinery package in combustion engine model to keep the particulates out of the engine compartment

or a dusty environment package in an electric

maybe even an explosion proof electric machine and battery depending on how dangerous the dust is (ee rated)

i have no experience with a customer like you
but
from what i read on the internet about manufacturing activated carbon it seems that the dust poses no special dangers that aren't associated with other small airborne particles but needs to be managed

That is a good question. We have a place up the road that makes carbon electrodes for steel mills, but they use IC trucks. The new generation of electrics use AC power and brushless motors, I wonder what effect it would have on the the rest of the electronics?
You might have to keep watching the Forum, someone will respond and may have an answer.