NFPA 652 Is Now NFPA 660: What Happened to the Combustible Dust Fundamentals Standard

By DHA Report Group · Updated October 20, 2026

If your dust hazard analysis (DHA), your insurer’s report, or your own procedures cite NFPA 652, you are working from a standard that no longer stands on its own. NFPA 652 was consolidated into NFPA 660, the single standard for combustible dusts and particulate solids. The short answer: the fundamentals did not go away. They moved.

Where NFPA 652 went

NFPA 652 was the fundamentals standard. It set the rules that applied to every combustible dust facility, no matter the material, and it is where the DHA requirement came from.

In NFPA 660, those fundamentals sit up front, in Chapters 1 through 10. They cover administration and definitions, hazard identification, the performance-based option, the DHA itself (Chapter 7), management systems, hazard management, and emergency planning and response.

The industry-specific requirements that used to live in separate standards follow in later chapters:

• Chapter 21: agricultural and food processing (formerly NFPA 61)
• Chapter 22: combustible metals (formerly NFPA 484)
• Chapter 23: sulfur (formerly NFPA 655)
• Chapter 24: wood processing and woodworking (formerly NFPA 664)
• Chapter 25: combustible dusts and particulate solids not otherwise specified (formerly NFPA 654)

You apply the fundamentals, plus the chapter for your material. The difference from before is that it is now one document instead of two or three.

What carried over from NFPA 652

• A DHA is required. NFPA 660 calls for one for any operation handling combustible dust, regardless of size, and it applies to existing facilities, not only new ones.
• A qualified person performs or leads it. NFPA 660 is clear that a credential such as PE, CSP, or CIH does not, by itself, make someone qualified. See who counts as a qualified person.
• The DHA is reviewed at least every five years and whenever your process changes. Most facilities only watch the first clock. See DHA revalidation.
• Management systems still matter. Housekeeping, ignition source control, training, management of change, and incident investigation all carry forward.

What actually changed for you

The biggest change is the references. NFPA 660 is organized differently, so a DHA, procedure, or training record that cites NFPA 652 section numbers will not line up with the current standard.

The second change is practical. If your facility handles more than one material, say wood and metal, you now work from one document.

For a broader look at the consolidation, see NFPA 660 explained or the NFPA 660 guide.

What to do with a DHA written to NFPA 652

NFPA 660 ties DHA reviews to two triggers: at least every five years, and whenever your process changes.

• When your next review is due, by either trigger, write it to NFPA 660.
• Old section references to NFPA 652 will not match NFPA 660, so updating them belongs in that review.
• No DHA at all: one should be written to NFPA 660 from the start.

Who this page is not for

If you are looking for the text of the standard, this is not it. NFPA publishes NFPA 660, and you can get it from NFPA directly. This page is for the person who needs to know what the change means for their facility and their DHA.

Keep reading

• What Is a Dust Hazard Analysis (DHA)? A Plain-Language Guide
• Does Your Facility Need a Dust Hazard Analysis (DHA)?

Questions about NFPA 652 and NFPA 660

Is NFPA 652 still a separate standard?

No. NFPA 652 was consolidated into NFPA 660. Its fundamentals, including the DHA requirement, now sit in Chapters 1 through 10 of NFPA 660.

Where is the DHA requirement in NFPA 660?

Chapter 7 of NFPA 660 covers the dust hazard analysis.

Do I need a new DHA because NFPA 652 was replaced?

NFPA 660 ties DHA reviews to two triggers: at least every five years, and whenever your process changes. When your next review is due, write it to NFPA 660 and update the old section references.

Did the DHA requirements change from NFPA 652 to NFPA 660?

The core expectations carried over: a qualified person, a review at least every five years and whenever the process changes, and safeguards based on your hazards. The organization and section numbers changed.

Do I still need my industry standard, like NFPA 61 or NFPA 664?

Those standards were also folded into NFPA 660. Your industry requirements now live in their own chapter of NFPA 660, applied along with the fundamentals.