A Crosswalk Is Not a Compliance Plan | Blog No. 139
Almost every PSM coordinator builds one eventually. A spreadsheet with the OSHA requirement in the left column, the EPA version next to it, and the IIAR standard that covers the same ground in the third. Green fill wherever the rows line up. It feels like progress, and for about a week it is.
Then somebody asks whether the crosswalk means you’re covered, and the honest answer is no.
I like crosswalks. They’re the fastest way to see which rulebooks are pointed at your ammonia system, so you don’t discover a fourth one halfway through an inspection. The trouble starts after the mapping is done, when people begin treating the spreadsheet as the compliance work instead of a table of contents for it. The spots where those rows quietly stop matching are the spots that get you cited.
The rows look identical because they mostly are
Set OSHA’s process safety rule next to EPA’s risk management rule and the overlap is almost eerie. Both want a process hazard analysis. Both want operating procedures, training, mechanical integrity, management of change, incident investigations, audits, and hot work permits.
That isn’t a coincidence. The CSB noted in its Tesoro Anacortes report that EPA built its prevention program on OSHA’s, and that much of the wording is identical. OSHA’s own small business guide puts it simply: apart from which agency enforces it and the plan you file with EPA, the two are nearly the same.
So people build the crosswalk, see the matching language, and figure one binder covers both agencies. That’s true often enough to be dangerous.
The pound numbers don’t cross over
Here’s the example I use when somebody shows me an all-green crosswalk.
OSHA covers anhydrous ammonia at 10,000 pounds. EPA covers anhydrous ammonia at 10,000 pounds. Same chemical, same number, green row, nobody argues.
Now put 25,000 pounds of 20 percent aqua ammonia on the property. OSHA has said in writing that when its list says “anhydrous,” it means anhydrous, and water solutions don’t count. So the OSHA rule doesn’t reach it. EPA, though, keeps a separate line for ammonia at 20 percent or stronger, and that one starts at 20,000 pounds. EPA’s rule reaches it just fine.
One tank. Same chemical. Two agencies, two different answers. A crosswalk organized by element name will never show you that.
The numbers also keep dropping the further you go from PSM. Community right-to-know reporting has no interest in your 10,000-pound line. Ammonia sits on the extremely hazardous substance list, so 500 pounds on the property is enough to owe notifications to your state, your local emergency planning committee, and the fire department. Release reporting is lower still. A hundred pounds out the door in a day and somebody is calling the National Response Center.
A hundred pounds is a serious release, and in my experience crews handle the response itself well. The reporting is what slips, because that obligation sits in a rulebook the PSM binder never mentions.
The two rules are protecting different people
OSHA’s rule is written to protect the people inside the fence. EPA’s exists because of the people outside it. OSHA says so plainly, and the difference is not academic.
Take the Cuisine Solutions plant in Sterling, the one the CSB investigated after its ammonia release. The offsite analysis for that site counted 17 public receptors inside a radius of just over a mile. A post office. Industrial parks. Two historical sites. A cemetery. A golf club.
Nothing in your OSHA paperwork will ever make you count a cemetery. That work exists only because a second agency is asking a different question about the same charge of ammonia.
Which is why the “equivalent” column is the weakest thing on most crosswalks. Two requirements can ask for the same document and still expect you to think about completely different consequences.
The IIAR column is a promise, not a reference
This is the one I see misread most often.
IIAR 6 says right up front that it’s voluntary unless your local authority makes it mandatory, and that an owner can adopt it on their own before anybody requires it. That second half trips people up. The moment you name IIAR 6 in your mechanical integrity program, you’ve chosen your good engineering practice, and OSHA can hold you to what that standard says about inspections and testing.
OSHA has been clear that you pick your own standards and that it accepts widely used industry ones. Picking is still a real decision, not a formality. Keith walked through the “shall” versus “should” side of it in Blog No. 119.
So a crosswalk row that reads “MI to IIAR 6” looks like a citation. It’s closer to a commitment.
IIAR 9 makes that sharper because it comes with a date. Existing systems were supposed to have their first minimum system safety evaluation done by January 1, 2026, then redone every five years. We’re eight months past that. If IIAR 9 is sitting in your crosswalk and nobody has run the evaluation, that row is recording a gap instead of closing one.
What I’d actually keep
Delete the “equivalent” column. It does the most damage, because it invites every reader to assume the work behind two rows is the same work. Replace it with “what this produces” and fill it with real records: the PHA revalidation, the relief valve replacement log, the yearly chemical inventory, the date your EPA plan goes back in. Now the crosswalk points at evidence instead of at other regulations.
Second, give pounds their own tab. Not yes or no, but real quantities and concentrations, with a name and a review date on every line. That’s the tab that catches the aqua ammonia problem, and it needs a look every time somebody adds a vessel or changes a charge.
Here’s the test I’d run on whatever crosswalk is on your shelf. Pick a green row at random and ask what document it produces and who is on the hook for keeping it current. If the spreadsheet can’t answer that, you’re looking at a picture of your program instead of the program itself.
Need help closing the gaps a crosswalk turns up? Macha PSM performs IIAR 9 Minimum System Safety Evaluations and full PSM and RMP program reviews for ammonia refrigeration facilities. Reach out, and we’ll walk your system with you.
For comprehensive training on Anhydrous Ammonia, click here for our PSM Academy Ammonia Awareness training to learn and earn a certificate of completion. Training is in English and Spanish. Use code SDS20 for a 20% discount on the entire purchase. For more information, email us at academy@machapsm.com.For a comprehensive training on Anhydrous Ammonia, click here for our PSM Academy Ammonia Awareness training to learn and earn a certificate of completion. Training is in English and Spanish. Use code SDS20 for a 20% discount on the entire purchase. For more information, email us at academy@machapsm.com.
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