Eleven people have now died from the sugar plant blast and more than 50 were injured after, it is thought, sugar dust in a silo where refined sugar was stored before packaging could have been ignited like gunpowder.
Experts at Chemical & Engineering News said this recent devastating explosion underscores the need for tougher industrial safety standards regarding the production of combustible dust.
As author Jeff Johnson explained that this is not a new issue: The US Chemical Safety Board (CSB) completed a study of combustible dust explosions in November 2006, as a result of which the US Occupational Safety and Health Administration (OSHA) called for more more safety regulations.
The systems that were introduced, however, did not meet all recommendations, said Johnson.
CSB and combustible dust
The CSB identified 281 combustible dust incidents between 1980 and 2005 that killed a total of 119 workers, injured 718, and extensively damaged industrial facilities.
A quarter of the explosions occurred in the food industry, including several at sugar plants.
Its interest in combustible dust was first heightened in 2003, when three separate dust accidents killed 14 workers, injured 77 and destroyed the plants.
The body said that sugar dust is combustible and static electricity, sparks from metal tools or cigarettes can ignite explosion.
Finer particles are more likely to be both ignitable and dispersible, and confined areas result in bigger explosions. Process equipment and ducting can create confinements for the explosion to travel along.
Chemical and Engineering News noted that opinion on necessary safety procedures has been divided. It said that, after its investigation, the CSM called for OSHA to issue a new national regulatory standard designed to prevent combustible dust fires and explosions in general industry.
But although many states and localities have adopted fire codes that have provisions related to combustible dust, a fire code officials rarely inspect industrial facilities to enforce the codes, said the publication.
The CSB also reviewed 140 material safety data sheets for combustible powders and found that in almost half the cases, manufacturers provided no warnings that the powders could explode.
The report also called for OSHA to require expanded dust warnings under its hazard communication standard, to provide training to inspectors on recognizing and preventing combustible dust explosions, and to implement an interim national Special Emphasis Program on combustible dust hazards in general industry.
The OSHA had already been investigating the area, and in conclusion did create a National Emphasis Program, but as a full measure as opposed to an interim one.
Chemical & Engineering News quoted Richard Fairfax, OSHA director of enforcement programs as saying: "We haven't gone out and rejected the board's recommendations. After we run this national emphasis program for a while, we will pull back and look at what we are citing and what we are finding."
While Fairfax acknowledged it is more difficult to enforce violations under the emphasis program than under a regulatory program, he said a combination of possible provisions may give inspectors enough authority to take actions that can reduce accidents.
The article said whether the blasts will trigger pressure that leads to a general dust regulation is yet to be seen.
However, in the publication's interview with Daniel Crowl, professor of chemical process safety at Michigan Technological University, he thought new concern will be kicked up from the accidents.
Crowl said: "Clearly, accidents are happening and people are not doing things properly. These explosions are entirely preventable.
Meanwhile, 150 workers returned to work at Imperial Sugar last week to ship out sugar supplies.