We are no longer surprised when we come across a “process” which is not a PSM-covered process because the facility has managed the quantity of their HHC below OSHA’s threshold. However, from a risk perspective, having 9,975 pounds of an HHC versus having 10,000 pounds does not lessen our process or personnel risks, but that is another discussion for a rainy day. Recently we came across an even more unique situation that nearly resulted in multiple contractors receiving serious burns when the flammable vapors ignited. The process was not covered by PSM/RMP because the “feed stock” was a Category 4 flammable liquid with a FP just under 190°F; however, this Category 4 flammable liquid was being heated to a temperature well above it’s flash point. Here’s what happened and how OSHA was at a loss to take action…

The process used a “feed stock” that was a waste stream from a sister plant. The waste stream solution had a high FP of just under 190°F and had a viscosity such that required the solution to be heated so it could be pumped more efficiently. In fact, the business determined that heating this solution up to 235°F had many benefits. In doing so, the facility was well aware of the requirement found in 1910.106(a)(19)(iv)…

Category 4 shall include liquids having flashpoints above 140°F (60°C) and at or below 199.4°F (93°C). When a Category 4 flammable liquid is heated for use to within 30°F (16.7°C) of its flashpoint, it shall be handled in accordance with the requirements for a Category 3 liquid with a flashpoint at or above 100°F (37.8°C).

So the facility was “sort of” managing this solution at a Category 3 flammable liquid and as many of you already know, a Cat 3 flammable liquid does not fall under PSM regardless of how many pounds you have on site/in-process. So the business viewed this as a win-win since they found a use for a waste stream from their primary business and the process using the stream did not have to be managed as a PSM process.

An error in judgement came when the facility did their risks assessment on this “process” and it’s Cat 4 flammable liquid when the topic of “Hazardous Location” came up. The engineering firm hired to perform this analysis was NOT informed that the facility would be heating up this solution to 235°F, ~50°F above it’s FP. They were merely told the facility would need to heat the solution to improve its ability to pump. The engineering company pointed out the requirement stated above regarding heating the solution to within 30 degrees of its flash point. And the facility recognized that requirement but lost sight of the requirements for a Hazardous Location (e.g. 1910.307).

So we now have several hundred thousand pounds of this Category 4 flammable liquid in a bulk tank farm. The tank farm was a “PSM tank farm” due to the other processes at the facility and the Cat 2 flammable liquids stored there. (NOTE: this company did not use the “meer decision” to exempt their flammable processes, an indication their intent was to do right when it came to process safety and their flammable liquids). The bulk storage tank for this Cat 4 flammable liquid had been modified by the installation of steam coils inside the bottom of the tank to aid in heating the material to keep it from “setting up”; however, it was NOT being heated to within 30° of its FP in the bulk tank within the tank farm.

The facility transferred the Cat 4 flammable liquid into any one of three (3) 7,500 gallon process vessels located inside the process building which had hot oil heating and agitation. This step could last up to 24 hours depending on the load on the hot oil heating system at other locations within the facility. However, it is in these vessels where the solution is heated to ~225-235°F (i.e. ~50°F above the FP). These three (3) vessels were designed for flammable liquid processing and the area these vessels were located was partly managed as a HAZLOC because the other HAZLOCs overlapped into this area. The facility, as well as the mis-informed engineering firm, did not recognize that this area should have been managed as a HAZLOC.

One day some contractors were working in the area and there was a significant release during the transfer from the heating tanks to the process and this ~235°F material spilled out onto the floor. The contractors did not recognize this as a significant hazard, nor did the operators in the area. This was compounded by the fact that the area was not designed like the other process areas (e.g. not a HAZLOC with rated equipment), the vessel labels stated the material was a “1” in the NFPA 704 Diamond for flammable hazard, and the contractors were allowed to work in the area without any special training, flame-retardant clothing, or safe work permit (different from their usual requirements when working in other process areas). In the video evidence, we could clearly see the solution spilling onto the floor and it was obvious the contractor personnel did not recognize the hazard this was creating (e.g. they did not evacuate the area), but they did pick up tools and equipment from the floor "so as to not get  them wet”. It took only 3 minutes and 20 seconds for the vapor to find an ignition source (later found to be a pump motor at ground level). It was pure luck that this incident occurred right about lunch time and thus the four (4) contractors had walked out of the area less than one-minute before ignition.

We were hired to work alongside the original engineering firm to investigate this incident and determine the failures that led to the incident, which resulted in no injuries but over $350,000 in damages. The investigation was unlike many we have done as the errors made were mostly “errors in judgment” by some very well trained and highly competent safety professionals and engineers. The one thing we all took away was that relying on OSHA’s framework of standards regarding flammable liquids has some serious gaps when we want to find them in order to save time and $. This company was embarrassed by the multiple decisions made and how everyone lined up looking for OSHA to force them to do the right thing rather than use their talents and knowledge to do the right thing (a paraphrase from the CEO). The only thing OSHA cited was 1910.307 and that was withdrawn once the lawyers got a hold of it. I am proud to say, the client now manages this process at BOTH facilities as a PSM-covered process, as well as other sub-processes where they heat up the flammable liquid above its FP.

So remember, true process safety is more than a highly hazardous chemical (HHC) and its threshold!

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