“A rule without exceptions is an instrument capable of doing mischief to the innocent and bringing grief—as well as injustice—to those who should gain exemptions from the rule’s functioning.” — Derrick Bell
I don’t remember when I first realized that there is a difference between process safety management and Process Safety Management. Process safety—the aspect of safety that addresses fires, explosions, and toxic releases in and from manufacturing processes—is mostly a concern of the chemical process industries, but not exclusively. It concerns itself with raw materials, intermediates, and finished products that can burn, that can explode, or that are toxic (and so a hazard when released).
That means that process safety management (all lower case) is the set of practices that controls the flammable, explosive, and toxic hazards of raw materials, intermediates, and finished products. Anyone working with materials with these properties should be practicing process safety management.
Process Safety Management (capitalized) is the name of a regulation promulgated and enforced by the Occupational Safety and Health Administration (OSHA) and found in 29 CFR 1910.119. Processes that are covered by the PSM Standard are covered because the PSM Standard says they are covered.
When does the PSM Standard say that a process is covered by the PSM Standard? When it exceeds the threshold quantity (TQ) of a limited number of toxic or reactive chemicals found in Appendix A of the Standard, or when it exceeds the TQ for flammable liquids or flammable gases.
Does the Whiskey Distillation Process Exceed the TQ?
The 137 chemicals in Appendix A made the list for a variety of reasons. While they are each toxic or reactive, that toxicity or reactivity ranges. As a result, the TQ for each also ranges, from as little as 100 pounds for sarin nerve gas to as much as 15,000 pounds for methyl chloride. Ethyl alcohol is not on the list. Anhydrous ammonia is, however, with a TQ of 10,000 pounds. This will only matter to distilleries if they use a large refrigeration system with anhydrous ammonia as the refrigerant. Otherwise, it would be a complete surprise to find any of the other chemicals from Appendix A at a distillery, much less more than their TQ.
Ethyl alcohol is not on the list in Appendix A. It is still covered by the PSM standard, though, because it is a flammable liquid. OSHA defines a flammable liquid as liquid with a flash point less than 100°F. The flash point of pure ethanol (100% ABV, or 200 proof) is 55°F (13 C). When diluted with water, the mixture gets less flammable, meaning the flash point increases. It is not until ethanol is diluted to 17.8% ABV (35.5 proof) that its flash point reaches 100°F (37.8 C) and is no longer defined as a flammable liquid by OSHA.
In a distillery, the mash is not a flammable liquid, and the wash is not a flammable liquid. Upon distillation, however, everything downstream is. The TQ for flammable liquids is 10,000 pounds. At 160 proof, which has a specific gravity of 0.861, the volume of 10,000 pounds is 1,394 gallons. The 4,500 gallon pot still at the Sugarlands Distillery Company operation in Kodak, Tennessee would exceed the flammable liquids TQ for PSM. Most craft distilleries don’t have this much volume tied up in their distillation process, so don’t exceed the TQ. It is important to keep in mind that the relevant amount is not the total amount of ethanol, but the total amount of flammable liquid. That is, the total amount of liquid at 35.5 proof or higher.
What About Proofing?
Before bourbon can go in a barrel, it must be diluted or “proofed” to 125 proof or less. That typically means adding water to the 160-proof liquor coming from the still, whether it is a pot still (batch) or column still (continuous). The specific gravity of spirits at 125 proof is 0.908, so the volume of 10,000 pounds is 1,321 gallons. As long as a proofing tank is less than 1,300 gallons, then, the proofing process will not exceed the TQ for the PSM standard. In other words, a proofing tank that can only fill 24 barrels or less will not be covered by the PSM Standard. Larger proofing tanks, however, will be. And if the distillation is connected directly to the proofing tank, that connection will mean that OSHA considers the distillation and proofing to be all one process, so distillation will be covered, too.
What About Storage?
Bourbon must age in new charred oak barrels, and many other spirits are aged in barrels as well. At 53 gallons per barrel, a traditional rickhouse storing 20,000 barrels contains about 8 million pounds of flammable liquid.
So, is a rickhouse covered under the PSM Standard?
It would be natural to assume that storage is not a process. But for the purposes of the PSM Standard, OSHA has defined “process” as “any activity involving a highly hazardous chemical including any use, storage, manufacturing, handling, or the on-site movement of such chemicals, or combination of these activities. For purposes of this definition, any group of vessels which are interconnected and separate vessels which are located such that a highly hazardous chemical could be involved in a potential release shall be considered a single process.
From that definition, a rickhouse with more than 24 barrels is a covered process. But…there is an exception. In 29 CFR 1910.119(a)(1)(ii)(B), OSHA makes an exception for “flammable liquids with a flashpoint below 100 °F (37.8 °C) stored in atmospheric tanks or transferred which are kept below their normal boiling point without benefit of chilling or refrigeration.” And to the relief of many, barrels qualify as atmospheric tanks.
So, no, a rickhouse is not a PSM-covered process.
And Blending and Final Proofing?
When a barrel has aged to the point that it is ready to be bottled, it is typically diluted again with water to its final proof. Regulations state that it cannot be less than 80 proof, but higher proofs also have a place in the market. Regardless, any spirit that is going into a bottle is a flammable liquid. Often, distillers will blend two or more barrels to achieve the flavor profile they want, then carefully dilute to the final proof. These steps, blending and proofing, are not storage, so do not qualify for the atmospheric storage exemption, even if the final proofing tank is an atmospheric tank.
At 80 proof, ethanol has a specific gravity of around 0.95, meaning that 10,000 pounds is 1,263 gallons. That is as big as a blending and final proofing tank can be without pushing the blending and final proofing process into the realm of being a PSM-covered process. It only takes about 800 gallons of barrel-strength whiskey to produce 1,263 gallons of 80 proof whiskey. That means that any blending and final proofing step involving more than 15 barrels of aged whiskey is going to be covered by the PSM Standard.
Why Does It Matter?
Craft distilleries have a lot to deal with in their efforts to satisfy the Alcohol and Tobacco Tax and Trade Bureau (TTB). They could hardly be faulted for not wanting to satisfy OSHA’s PSM Standard with its 14 elements. Not that it’s beyond their ability. Small companies all over the country operate PSM-covered processes.
There is an OSHA letter of interpretation, dated 14-Mar-2003, and addressed to the Commonwealth of Kentucky, where OSHA states that they will limit enforcement of the PSM standard “within the distilled spirits industry, where PSM citations will be issued only in the event of a fatality or catastrophe involving a process that uses ethyl alcohol in a distillery or its related facilities in SIC 2085.”
So, as long as nothing goes wrong, OSHA is not going to enforce PSM. If something does go wrong, however, all bets are off.
Is that a chance worth taking?
