Dust Hazard Analysis (DHA) for Woodworking Shops and Mills

By DHA Report Group · Updated October 20, 2026

Wood dust is the combustible dust most people have seen with their own eyes. If you run a cabinet shop, a millwork plant, a furniture operation, a truss plant, or a sawmill, you make it every day. The standard that used to cover wood, NFPA 664, is now part of NFPA 660, and your dust hazard analysis (DHA) is written to that.

Not all wood dust is equal

Chips and shavings from a planer are large and heavy. Sanding dust is fine and light, stays in the air longer, and ignites much more easily. Most wood shops have both, and a DHA treats them differently. The fine dust from wide-belt sanders, CNC routers, and hand sanding stations usually drives the biggest findings.

Where a DHA looks in a wood shop

• Machines and pickups. Saws, planers, moulders, routers, CNCs, and sanders, and how well each hood captures dust.
• Ductwork. Duct sizing, air velocity to keep dust moving, clean-outs, and where dust settles inside ducts.
• Dust collectors and cyclones. Location, explosion protection, isolation back toward the building, and how collected dust is discharged.
• Storage. Silos, bins, trailers, and bagged dust.
• Spark and ember sources. Saws hitting metal, sanders, and anything that can send a hot particle down the duct.
• The building. Dust on rafters, lights, and the tops of machines and walls.

Common gaps in wood facilities

• Undersized or low-velocity ductwork that lets dust drop out and build up inside the duct.
• No spark detection on ducts serving sanders and high-speed machines.
• Indoor collectors with no venting, isolation, or suppression.
• No isolation between an outdoor collector and the building, so a problem at the collector can travel back through the duct.
• Heavy overhead accumulation on rafters and light fixtures.
• Blowing down with compressed air instead of vacuuming.
• Portable shop vacuums not rated for combustible dust.

What to have ready

A layout with machines and duct runs marked, photos of your collectors and overhead areas, collector make and model, and any dust test data. Most wood shops can be studied remotely. For pricing, see what a DHA costs in 2026.

Keep reading

• NFPA 664 Is Now NFPA 660: What It Means for Woodworking Facilities
• Combustible Dust Housekeeping Under NFPA 660
• Dust Collector Explosion Protection: Venting, Isolation, and Suppression Explained
• Dust Hazard Analysis (DHA) for Paper, Tissue, and Corrugated Plants

Questions from wood shops

Is sawdust a combustible dust?

Usually, yes. Fine wood dust is combustible, and sanding dust is the most easily ignited. Coarse chips and shavings are usually not a deflagration risk unless the fines separate out and build up.

Does a small cabinet shop need a DHA?

If you make combustible wood dust, NFPA 660 expects a DHA. The study scales with your shop, so a small shop gets a smaller scope.

What standard covered wood dust before NFPA 660?

NFPA 664. Its requirements are now consolidated into NFPA 660.

Do I need spark detection on my ductwork?

It depends on your machines and collector setup. Spark detection is a common DHA recommendation on ducts serving sanders and high-speed equipment.