What Is a Dust Hazard Analysis (DHA)? A Plain-Language Guide

By DHA Report Group · Updated October 5, 2026

If your insurer, a customer, or your own safety team has asked you for a dust hazard analysis (DHA), you may be wondering what you are actually being asked for. A DHA is a documented, systematic review of your plant that identifies where combustible dust could cause a fire, a flash fire, or an explosion. It evaluates the safeguards you have in place today and recommends what to add or change, following NFPA 660.

What a DHA looks at

A DHA works through your plant in three passes. Each one answers a different question.

• Your materials. Which of the dusts you make or handle can burn, and how do you know? That may come from lab test results, Safety Data Sheets, or published data used for screening. A DHA can also treat a dust as combustible without testing.
• Your process equipment. Every piece of equipment that makes, moves, stores, or collects dust gets reviewed. Think mixers, mills, conveyors, bins, dryers, ductwork, and dust collectors. For each one the study asks where dust can build up or become airborne, what could ignite it, and what is in place to prevent or limit an event.
• Your building areas. Rooms and spaces where dust escapes and settles are part of the study too. That includes floors, ledges, beams, tops of equipment, and the areas above ceilings.

What a DHA produces

You get a written report. The core of it is a set of findings and recommendations.

• Findings. For each piece of equipment and each building area, the report states whether a fire, flash fire, or explosion hazard exists and why.
• Existing safeguards. The report lists what you already have, such as venting, isolation, grounding and bonding, spark detection, and housekeeping procedures.
• Recommendations. Where a gap exists, the report says what to change. A good report ranks the recommendations so you know what to work on first.

The report does not fix anything by itself. It is the plan you work from, and the record that shows you looked. For a section-by-section walk through, see what is in a DHA report.

Who is responsible for the DHA

You are, if you own or operate the facility. NFPA 660 places the responsibility for having a DHA on the owner or operator. The work can be done by your own team or by someone on your behalf.

Either way, the study must be led by a qualified person. A credential alone, such as a PE, CSP, or CIH, does not make someone qualified. Hands-on experience assessing combustible dust hazards does. More on that in who counts as a qualified person.

A DHA is also not a one-time document. NFPA 660 calls for it to be reviewed and updated at least every five years, and whenever your process changes. See when your DHA is due for revalidation.

How a DHA differs from an inspection or a dust test

These three get mixed up often, and it is easy to see why. They overlap, but each does a different job.

• An inspection is a look at conditions on a given day. Someone walks the plant and notes what they see, such as dust on a beam or a missing ground strap. It tells you what was found. It does not analyze how your process could fail.
• A dust test is lab work on a sample of your material. A go/no-go screening test tells you whether the dust is explosible at all. Further tests measure Kst, Pmax, MEC, and MIE, covered in combustible dust testing explained. The results describe the dust. They say nothing about your equipment or your building.
• A DHA puts the pieces together. It takes what is known about your dust, your equipment, and your building, and works out where the hazards are and what to do about them.

Test results and inspection notes are useful inputs to a DHA. Neither one replaces it.

When you do not need a DHA, or do not need us

Not every dusty plant needs one. If none of your materials are combustible, NFPA 660 does not ask you for a DHA. Sand, glass, and many mineral dusts fall in that group. If you are not sure where you stand, start with does my facility need a DHA.

You may also not need us in particular:

• You have a qualified person on staff. Your own team can lead the DHA. Nothing says it has to come from outside.
• You need a stamped report. We do not provide a PE stamp and do not stamp drawings. Your own PE can review our report.
• You are shopping for equipment. We do not sell dust collectors or any other equipment. We write the study.

How a DHA usually gets done

We write DHAs to NFPA 660 for plants in all 50 states. Most are done remotely from your drawings, photos, and process information. Each one is quoted from your own intake and documents, so the scope fits your plant.

Questions about what a DHA is

What is a dust hazard analysis in simple terms?

It is a documented review of your plant that identifies where combustible dust could cause a fire, flash fire, or explosion. It also recommends what to add or change.

Is a DHA the same as a dust test?

No. A dust test measures the properties of a sample of your material in a lab. A DHA uses what is known about your dust to review your equipment and building.

Who is responsible for having a DHA?

The owner or operator of the facility. The study can be completed by the owner or by a qualified person on the owner’s behalf.

Is a DHA a one-time document?

NFPA 660 calls for a DHA to be reviewed and updated at least every five years, and whenever the process changes.

Can a DHA be done without testing my dust?

Yes. A DHA can treat a dust as combustible without testing. Lab testing of your actual dust is needed when explosion protection is being designed.