Click the link at the top of the page, "
Read the last information", for Petzl's detailed analysis of the two failed units, which had been used in a highly-corrosive offshore setting.
The frequency of this in-service failure of the CROLL is exceptionally low (two in hundreds of thousands). However, Petzl recommends:
4-1: When used in a corrosive environment, rinse and dry any Petzl metallic PPE after each use in order to limit potential corrosion issues (particularly in the hidden/confined areas).
4-2: In accordance with existing Petzl recommendations, when connected to a rope clamp, the user must have a backup device or a connection to a second rope clamp (secondary means of support).
4-3: Users visually inspect their CROLL B16 & B16AAA to check that the rivet head is not missing.
Petzl requests that this information be made available to all those who work with, maintain, and inspect Petzl CROLL rope clamps, and strongly suggests that the recommendations listed above be put into effect.
To paraphrase their conclusions: The Petzl Croll is not "corrosion proof". Corrosion-proof steel has mechanical properties unsuitable for use in the product. Corrosion-compromised stainless steel is difficult to visually inspect. If you use the Croll in a highly-corrosive environment, you should inspect your gear frequently, retire it early.
There is no recall, and no reason to be concerned if you only use your vertical gear in an uncorrosive limestone cave. If you frequent H2SO4 caves... your nylon harness will probably kill you before your Croll does!