UNITED STATES
DEPARTMENT OF LABOR

Text For Citation: 01 Item/Group: 001 Hazard:

OSH ACT of 1970 Section (5)(a)(1): The employer did not furnish employment and a place of employment which were free from recognized hazards that were causing or likely to cause death or serious physical harm to employees: a) The employer is exposing employees working at its facility located at 4444 S. 76th Circle, Omaha, NE 68127 to the recognized hazard of fire, deflagration and explosion associated with using compressed air to blow accumulations of combustible dust off of surfaces and equipment in the presence of potential ignition sources creating dust clouds. The most recent examples of this occurred on January 20, 2014 when the employer had employees cleaning the facility with compressed air without eliminating all potential ignition sources. Among other methods, feasible and acceptable methods of abatement are: 1. Complying with applicable provisions of NFPA 654: Standard for the Prevention of Fire and Dust Explosions From the Manufacturing, Processing and Handling of Combustible Particulate Solids, concerning use of compressed air. (See, 2013 edition including Sections 8.2.2, 8.2.2.4.) 2. The employer upgrading all the electrical in the facility that is near potential combustible dust locations to Division II Class II wiring. 3. The employer providing employees with additional training on the recognition of potential ignition sources and the use of compressed air, specifically addressing the need to de-energize all potential ignition sources. 4. The employer developing and implementing in depth written procedures specifically for the purpose of using compressed air for cleaning the facility, paying particular attention to the issues of combustible dust and de-energizing potential ignition sources. b) The employer is exposing employees working at its facility located at 4444 S. 76th Circle, Omaha, NE 68127 to the recognized hazard of fire, deflagration and explosion associated with operating equipment that conveys materials that contain or generate combustible dust with the panel doors removed so that combustible dust escapes into the atmosphere. The most recent example of this occurred on January 20, 2014 when the employer allowed employees working on bagging line #4 at the facility to operate the Inglet Scale conveyor belt system with the panel doors removed, allowing combustible dust generated during the handling of product to escape into the atmosphere creating the danger of a fire, deflagration, and/or explosion. On that day, access doors were open and covered with an approximately 1/8 inch layer of dust accumulation. The Inglett Scale conveyor belt enclosure provides a 5-sided exhaust hood to capture dusting from material transport dust emission sources such as impact at belt loading point, belt return idlers and belt discharge to the filling spout hopper. With the panel doors removed, the enclosure is compromised and belt dusting becomes fugitive dust resulting in dust accumulations on horizontal surfaces in the surrounding packaging area. If dispersed and ignited, the dust accumulations on horizontal surfaces can contribute to a secondary explosion in the packaging area as settled dust accumulations are lifted, ignited, deflagrate and possibly explode. Potential ignition sources include static electricity discharge from lack of electrical bonding of non-conductive, rubber flex hose at hood connections, hot foreign material from upstream failed equipment, upstream fire, etc. Among other methods, feasible and acceptable methods of abatement are: 1. Complying with applicable provisions of NFPA 654: Standard for the Prevention of Fire and Dust Explosions From the Manufacturing, Processing and Handling of Combustible Particulate Solids, (2000 edition), including Sections 4.1, 4.2.1. 2. Implementing a work practice to reinstall the panel doors on the Inglet Scale conveyor belt system after maintenance/cleaning before the packaging line is used. 3. Implementing a work rule prohibiting operation of the Inglet Scale conveyor belt system with the panel door removed. 4. Installing a proof-of-closure switch could be installed on each panel door to prevent the operation of Inglet Scale conveyor belt system without closing the panel door. c) The employer is exposing employees working at its facility located at 4444 S. 76th Circle, Omaha, NE 68127 to the recognized hazard of fire, deflagration and explosion associated with using non-conductive, un-bonded synthetic flexible duct as part of the dust collection system handling combustible dust. The most recent example of this occurred on January 20, 2014 at the facility where the employer allowed, at the dust collector for bagging line #4, use of un-bonded synthetic flexible duct as part of the dust collection system, creating the potential for static charge to build up as product passes through the flex duct and increasing the possibility of sparking the combustible dust and creating a deflagration ultimately leading to a secondary combustible dust explosion. The non-conductive flexible duct conveys combustible dust. Non-conductive flexible ducts without bonding allow electrostatic charges to accumulate at the discontinuity where bonding is lost while product is flowing. Discharge of the accumulated electrostatic charges can be an ignition source for a combustible dust fire, deflagration and explosion in the dust collecting system. Among other methods, feasible and acceptable methods of abatement are: 1. Complying with applicable provisions of NFPA 654: Standard for the Prevention of Fire and Dust Explosions From the Manufacturing, Processing and Handling of Combustible Particulate Solids, (2000 edition), including Section 5.3.1. 2. Replacing the electrically non-conductive flex duct with an electrically conductive duct. 3. Bridging the non-conductive flex duct with a conductive cable bonding the metal duct and hood to each other with both options insure that the exhaust system is grounded. 4. In conjunction with both 1 and 2, insuring the exhaust system is grounded. d) The employer is exposing employees working at its facility located at 4444 S. 76th Circle, Omaha, NE 68127 to the recognized hazard of fire, deflagration and explosion associated with loss-of-flow in the dust collection system handling combustible dust. The most recent example of this occurred on January 20, 2014 at the facility where the employer allowed the dust collection system handling combustible dust to be operated with reduced flow as a result of the following defects: 1. One of the 4¿ diameter exhaust ducts serving the exhaust hoods at packaging line #4 was plugged with a paper bag. 2. Many of the 4¿ diameter, flexible exhaust ducts serving the exhaust hoods at packaging line #4 had holes in them. The holes in the flexible duct allow exhaust air, needed at the hood, to short circuit and enter at the hole. Both 1 and 2 result in reduced exhaust air volumetric capacity at the respective hoods within the dust collection system. The ability of the hoods to capture dust emissions from packaging is reduced, and consequently, more fugitive combustible dust from the packaging operation accumulates on the floor. Among other methods, feasible and acceptable methods of abatement are: 1. Complying with applicable provisions of NFPA 654: Standard for the Prevention of Fire and Dust Explosions From the Manufacturing, Processing and Handling of Combustible Particulate Solids, (2000 edition), including Section 4.2.1. 2. Inspecting the bagging conveyor line for blockages, and where torn bags could be sucked into the hoods, using smoke trails to check hood performance and find any blockages. 3. Replacing flex duct when holes are evident. e) The employer is exposing employees working at its facility located at 4444 S. 76th Circle, Omaha, NE 68127 to the recognized hazard of fire, deflagration and explosion associated with operating a dust collection system handling combustible dust that failed to contain isolation devices to prevent deflagration propagation in the event of a deflagration in the dust collector. The most recent example of this occurred on January 20, 2014 at the facility where the employer allowed the production lines to operate using a MAC dust collector that failed to have isolation devices at various locations throughout the system: i. The system failed have an isolation device to prevent dust collector deflagration propagation through upstream ductwork to the work areas (e.g., mixers, conveyors, packaging, etc.) in the event of a deflagration in the dust collector. This event may lead to a secondary explosion in the work space as settled dust accumulations are lifted, ignited, deflagrate and possibly explode the building causing a catastrophic collapse of the structure. ii. The system failed to have an isolation device to prevent dust collector deflagration propagation through downstream exhaust ductwork (recycled air back into the building) in the event of a deflagration in the dust collector. This event may lead to a secondary explosion in the work space as settled combustible dust accumulations are lifted, ignited, deflagrate and possibly explode the building causing a catastrophic collapse of the structure. iii. The system failed to have an isolation device to prevent dust collector deflagration propagation from the dust collector hopper to the dust collector storage barrel in the event of a deflagration of the dust collector. This event may lead to a secondary explosion in the loading dock area where the dust collector storage barrel is located. The combustible dust in the dust collector hopper passes through a rotary valve and screw conveyor before falling into 55 gallon metal barrels in the loading dock. Neither the rotary valve or screw conveyor have the ability to act as an isolation choke to prevent a fire or deflagration from propagating from the dust collector to the storage barrels. Dust collectors can deflagrate when the bags are pneumatically pulsed during normal operation, creating a combustible dust cloud at minimum explosive concentration within the dust collector housing. In the presence of an ignition source, the dust collector will experience a flash fire, deflagration, or explosion. Potential ignition sources include static electricity discharge from lack of electrical bonding of non-conductive flexible ducts, hot foreign material from upstream failed equipment, upstream fire, etc. Among other methods, feasible and acceptable methods of abatement are: 1. Complying with applicable provisions of NFPA 654: Standard for the Prevention of Fire and Dust Explosions From the Manufacturing, Processing and Handling of Combustible Particulate Solids, (2000 edition), including Sections 3.1.3.1, 3.1.3.2, 3.13.7, and 2.1.3. 2. Installation of isolation devices at all required locations pursuant to NFPA 654, Section 3 requirements. These include chokes rotary valves, fast acting isolation valves, flame front diverters, and flame front extinguishers. 3. Design of the dust collection system so that it prevents both return of dust with an efficiency of 99.9% at 10 microns and transmission of energy from a fire or explosion to the building. Such a design allows recycling of dust collector exhaust air.