UNDERSTANDING DHA
What Is a Dust Hazard Analysis?
A Dust Hazard Analysis is a systematic, documented review of combustible dust hazards in your facility — now mandated by NFPA 660-2025 and enforced through OSHA's General Duty Clause.
THE DEFINITION
A Structured Methodology for Identifying and Controlling Combustible Dust Risk
A Dust Hazard Analysis (DHA) is a formal engineering review that systematically identifies, evaluates, and documents combustible dust hazards within a facility. It examines how dust is generated, how it accumulates and disperses, what ignition sources are present, and what the consequences of a fire or explosion could be — including both intended and unintended transportation of combustible dust through the facility.
The DHA must be led by a qualified person — a trained engineer or certified safety professional with demonstrated expertise in combustible dust hazard evaluation. The process includes physical dust sampling for laboratory testing, photographic documentation of areas of interest, identification of safe operating ranges, and a review of on-site training programs and emergency response procedures.
The output is a defensible, audit-ready written report with findings, risk rankings, recommendations for additional safety improvements, and a prioritized corrective action plan. Under NFPA 660-2025, DHA reports must be reviewed and updated every five years — or sooner if process changes occur that may significantly alter the original findings.
REGULATORY FRAMEWORK
Two Independent Mandates — Both Apply to Your Facility
NFPA 660-2025 consolidates and supersedes multiple previous NFPA combustible dust standards (including NFPA 61, 484, 654, 655, and 664). It explicitly requires facilities that handle, process, or generate combustible dust to conduct a Dust Hazard Analysis. The standard specifies the scope, methodology, documentation requirements, and review frequency for DHAs.
- Applies to new and existing facilities
- Specifies DHA methodology and documentation requirements
- DHA reports must be updated every 5 years — or sooner if process changes alter the original findings
- Effective for the 2025 edition — compliance required now
The OSHA General Duty Clause requires employers to provide a workplace free from recognized hazards that are causing or likely to cause death or serious physical harm. Combustible dust is a well-documented, recognized hazard. OSHA has used the General Duty Clause extensively to cite facilities for combustible dust violations — even in the absence of a specific OSHA combustible dust standard.
- Applies to all employers regardless of industry
- OSHA actively cites combustible dust under this clause
- Willful violations carry fines up to $156,259 per instance
- A completed DHA is your primary evidence of due diligence
WHAT A DHA COVERS
A Comprehensive Review of Your Facility's Combustible Dust Hazards
Qualified Person Leadership
The DHA must be led by a qualified person — an engineer or safety professional with demonstrated expertise in combustible dust hazard evaluation, NFPA 660-2025 methodology, and process safety management.
Dust Accumulation & Dispersion
Systematic evaluation of how dust accumulates on floors, equipment, elevated surfaces, and inside enclosures — and how it disperses through the facility under normal and upset operating conditions.
Dust Transportation Pathways
Analysis of both intended transportation (conveying systems, pneumatic transfer, baghouses) and unintended transportation (air currents, vibration, equipment leaks) that can spread combustible dust to new hazard areas.
Dust Sampling & Laboratory Testing
Physical collection of dust samples from representative areas throughout the facility for laboratory analysis — determining Kst, Pmax, minimum ignition energy, minimum explosive concentration, and other critical explosion parameters.
Photographic Documentation
Comprehensive photographic record of all areas of interest — accumulation zones, ignition sources, existing controls, equipment conditions, and housekeeping concerns — providing visual evidence to support findings.
Ignition Source Inventory
Documentation of all potential ignition sources — electrical equipment, hot work, friction, static electricity, open flames, and mechanical sparks — and evaluation of their proximity to dust hazard areas.
Safe Operating Ranges
Identification and documentation of safe operating parameters for dust-generating processes — including maximum allowable dust concentrations, housekeeping frequencies, and equipment operating limits.
Training & Emergency Procedures Review
Evaluation of on-site training programs, emergency response procedures, and the steps in place to handle combustible dust incidents — identifying gaps and recommending improvements to protect workers.
Explosion Scenario Analysis
Evaluation of credible fire and explosion scenarios, including primary and secondary explosion potential, deflagration propagation pathways, and consequence severity for each identified hazard area.
Existing Controls Assessment
Review of current dust control measures, explosion protection systems, and administrative controls — identifying gaps relative to NFPA 660-2025 requirements and recommending additional safety improvements.
WHAT YOU RECEIVE
A Written Report That Stands Up to Regulatory Scrutiny
Written DHA Report
A comprehensive, signed document meeting NFPA 660-2025 requirements — prepared by a qualified person and suitable for presentation to OSHA inspectors, insurance carriers, and facility management.
Dust Sample Test Results & Photo Documentation
Laboratory analysis of collected dust samples (Kst, Pmax, MIE, MEC) paired with a photographic record of all areas of interest — providing the physical evidence base for every finding in the report.
Compliance Gap Analysis
A clear comparison of your current facility conditions against NFPA 660-2025 requirements — showing exactly where gaps exist, what safe operating ranges apply, and what must be addressed.
Prioritized Action Plan
A ranked list of corrective actions and recommended safety improvements with timelines, responsible parties, and estimated implementation costs — your clear roadmap to full compliance.
5-Year Review Schedule
Documentation of the required DHA review cycle — reports must be updated every five years, or sooner if process changes occur that may significantly alter the original hazard findings.
Ready to Schedule Your DHA?
Our qualified engineers guide you through every step of the process — from initial facility walkthrough to final written report.