Clothing such as steel toe boots, belt buckles, watches, or even metal buttons can cause a spark when the wearer moves around. If the facility is full of combustible dust hazards that little spark can ignite the dust cloud, leading to a devastating combustible dust explosion.
NFPA 484 (Combustible Metals) requires:
• Static dissipative shoes for Aluminum, Niobium, Tantalum
• Non-sparking shoes for Titanium and Zirconium
• No exposed metal on shoes for Magnesium
• Evaluate need for static dissipative shoes for metals not specifically covered in NFPA 484
• No exposed metal on shoes
• “Appropriate for the type of operation”
• Clothing requirements vary – generally flame retardant but may also require non-static generating for Aluminum and “metals not specifically covered”