Find out from the American Conference of Industrial Hygienists (ACGHI) and from NIOSH the acceptable dust concentration (i.e. TLV) within the work area; use the most stringent TLV form ACGHI or NIOSH; estimate the generation rate of the dust from the pot and base your ventilation rate to keep the work area at an acceptable concentration level. Note the acceptable concentration "MAY" be based on a percentage of the ACGHI or NIOSH TLV for that dust. In addition to an acceptable ventilation rate, there may be requirement for hygiene practices. Also instead of a general ventilation within the room check out a dedicated ventilation system for the pot area. One last option is to provide the worker with respiratory protection either with half face or full face respirators or with PAPR equipment fitted with the proper filters for that dust, however, respiratory protection will need to comply with OSHA regulation on respiratory protection.