I hope that in today’s workplaces, everyone knows we do NOT “splash fill” flammable liquids. However, this simple fact is often overlooked or unknown when adding a non-flammable solution to a flammable one. Its not the product that matters, it’s the free fall that creates the static within the flammable atmosphere.
This is a classic case of static electricity being the ignition source for a flammable vapor. The kettle contained alcohol; another non-flammable solution was then added to it. This added solution allows for free-fall into the kettle, as well as splashing into the alcohol (splash filling), generating sufficient static to be an ignition source for the alcohol vapors.
At 11:00 a.m. on July 7, 2020, an employee, 33, was standing on a ladder, pouring caramel-colored liquid from its storage container into a 500-gallon batch of rum being made in a 1250-gallon tank. As the employee began to pour the caramel, a flash occurred due to an electrostatic discharge that contacted the alcohol vapors, causing the employee to jump from the ladder. The employee was wearing safety glasses and earplugs, but sustained flash burns to his right hand, lower arm, and singed hair, and was hospitalized for treatment. The cause was an electrostatic discharge near the alcohol vapors.
Source: https://www.osha.gov/ords/imis/accidentsearch.accident_detail?id=128142.015