Based on my limited experience dealing with the issue (wasn't just chromium exposure, but also other issues as well)

IF you are subject to the requirements (have employees that may be exposed), AND a case can be made by the inspector that there may be a level that exceeds the action level (which is LESS than the maximum allowable), you need to deal with it. They don't need to show that you DO exceed the action level to make your life difficult, only to fine you (though you can be fined for procedural and documentation issues even if you don't violate the standard)

You may be able to establish without testing that the exposure is not likely to be exceed the action level based on standard data, but it isn't going to be easy if you deal with any stainless. Yes, they need to demonstrate that you have exceeded before you can be penalized (if they don't demonstrate this, your attorney will giggle like a schoolgirl on the way to court), but you don't want to go there. It is NOT cheap at that point. If there is concern expressed, you MUST test to avoid liability.

The standards require that you establish that you test first. Initial sampling and testing to determine WHAT the potential exposure is easiest if you bring in someone with the right gear to do the job. The setup I am familiar with (not the only way) used a sampler on a belt clip pump sampler with a tube on a neck lanyard to hold the inlet end near the mouth and nose. Wear it for a shift and the collected sample is tested and the result is calculated based on how much air was drawn through the unit. I don't know what it cost, but a commercial service came in with the units and did the evaluation. It didn't break the bank. A set of parameters came out of this for which the action level should not be exceeded and no further testing is needed.

The requirement is engineering controls if practical, PPE if engineering controls don't do the job, and testing after implementation to insure that the engineering controls/PPE do control the exposure.