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(A) Section 1301 General

(1) 1301.1 Scope. The equipment, processes and operations involving dust explosion hazards shall comply with the provisions of this rule.

(2) 1301.2 Permits. Permits shall be required for combustible dust-producing operations as set forth in rule 1301:7-7-01 of the Administrative Code.

(B) Section 1302 Definitions

(1) 1302.1 Definition. The following word and term shall, for the purposes of this rule and as used elsewhere in this code, have the meaning shown herein.

"Combustible dust." Finely divided solid material which is 420 microns or less in diameter and which, when dispersed in air in the proper proportions, could be ignited by a flame, spark or other source of ignition. Combustible dust will pass through a U.S. No. 40 standard sieve.

(C) Section 1303 Precautions

(1) 1303.1 Sources of ignition. Smoking or the use of heating or other devices employing an open flame, or the use of spark-producing equipment is prohibited in areas where combustible dust is generated, stored, manufactured, processed or handled.

(2) 1303.2 Housekeeping. Accumulation of combustible dust shall be kept to a minimum in the interior of buildings. Accumulated combustible dust shall be collected by vacuum cleaning or other means that will not place combustible dust into suspension in air. Forced air or similar methods shall not be used to remove dust from surfaces.

(D) Section 1304 Explosion protection

(1) 1304.1 Standards. The fire code official is authorized to enforce applicable provisions of the codes and standards listed in Table 1304.1 of this rule to prevent and control dust explosions.

Table 1304.1 Explosion protection standards

Standard Subject
NFPA 61 as listed in rule 1301:7-7-47 of the Administrative Code Agriculture and food products
NFPA 69 as listed in rule 1301:7-7-47 of the Administrative Code Explosion prevention
NFPA 70 as listed in rule 1301:7-7-47 of the Administrative Code National Electrical Code
NFPA 85 as listed in rule 1301:7-7-47 of the Administrative Code Boiler and combustion systems hazards
NFPA 120 as listed in rule 1301:7-7-47 of the Administrative Code Coal preparation plants
NFPA 484 as listed in rule 1301:7-7-47 of the Administrative Code Combustible metals, metal powders and metal dusts
NFPA 654 as listed in rule 1301:7-7-47 of the Administrative Code Manufacturing, processing and handling of combustible particulate solids
NFPA 655 as listed in rule 1301:7-7-47 of the Administrative Code Prevention of sulfur fires and explosions
NFPA 664 as listed in rule 1301:7-7-47 of the Administrative Code Prevention of fires and explosions in wood processing and woodworking facilities


Replaces: 1301:7-7-13

Effective: 11/01/2011

R.C. 119.032 review dates: 11/01/2016

Promulgated Under: 119.03

Statutory Authority: 3737.22 , 3737.82

Rule Amplifies: 3737.22 , 3737.82

Prior Effective Dates: 7/1/79, 6/1/85, 6/15/92, 7/1/93, 9/1/95, 3/30/98, 1/3/00, 9/1/05, 7/1/07

The flash fire that burned seven workers, one seriously, in 2012 resulted from the accumulation of combustible dust inside a poorly designed dust collection system that had been put into operation only four days before the accident.  The CSB  investigation team concludes that the system was so flawed it only took a day to accumulate enough combustible dust and hydrocarbons in the duct work to overheat, ignite spontaneously, cause an explosion in the rooftop dust collector, and send back a fiery flash that enveloped seven workers.  The CSB found that the ductwork conveyed combustible, condensable vapors above each of three tanks in the mixing room, combining with combustible particles of dust of carbon black and Gilsonite used in the production of black ink.  The closed system air flow was insufficient to keep dust and sludge from accumulating inside the air ducts.  But to make matters worse, the new dust collector design included three vacuuming hoses which were attached to the closed-system ductwork, used to pick up accumulated dust, dirt and other material from the facility’s floor and other level surfaces as a ‘housekeeping’ measure.  The addition of these contaminants to the system ductwork doomed it to be plugged within days of startup.  The report describes a dramatic series of events that took place within minutes on October 9, 2012...

UPDATE on 7/21/14The Jan. 20 structural collapse was caused by overloading nine storage bins on the building's roof level, an OSHA investigation has found. The collapse at the livestock feed supplement manufacturer caused the death of two workers and injuries to nine others.  The investigation determined a structural failure of the east side truss, after bins that it supported were loaded with an excess of limestone. The extra weight caused the bins to collapse three floors into the center of the facility in about 30 seconds.  As a result of the tragic incident, OSHA has cited the company with one willful, one repeat and 11 additional safety violations for failing to protect workers from hazards associated with structural collapse.

CLICK HERE for the citations

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As end-of-summer harvest time nears, grain storage facilities will be gearing up to accept crops from farmers’ fields. Many of these products produce combustible dusts that can result in catastrophic explosions when there is a suitable mix of air and fuel, as well as an ignition source such as a hot bearing, overheated motor, misaligned conveyor belt, or when welding, cutting and brazing are taking place.

According to U.S. Department of Labor statistics, since 1976, there have been 503 grain elevator explosions in the United States, resulting in 184 deaths and 677 injuries. The likelihood, severity and lethality of grain dust explosions and fires can be reduced by a few simple safety precautions.

Today in Omaha, NE there was an industrial accident at a business where one would expect to find combustible dusts. The accident resulted in several employees being treated for burns and there are two confirmed fatalities as of this evening. And although, we were quick to point out this accident may have involved a combustible dust explosion I now believe that the collapse of the structure was the initiating event and any fires and explosions were secondary to the collapse. Bear in mind this is a THEORY based solely on photographic evidence from OUTSIDE the facility; however, these photographs provide very strong evidence to back up my theory. Using my cause and origin investigation skills from way back in the day I can see (and NOT see) the following using the aerial photos provided by the Omaha Herald (

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