Warehouse workers around the world are being told to kick bags of nickel to make sure they're not filled with stones like JPMorgan recently discovered

• The London Metal Exchange announced irregularities in its nickel contracts earlier this month.
• More than a million dollars of supposed nickel that belonged to JPMorgan was actually discovered as bags of stones.

Last week's revelation that JPMorgan's bags of nickel were actually bags of stones seemed nothing short of a fable.

The mega-bank had stored bags of what was presumed to be 54 metric tons of nickel at a warehouse in the Dutch city of Rotterdam. Yet when the bags were weighed earlier this month, it turned out that they were filled with stones instead of nickel briquettes.

Since then, the tale has only continued, with warehouse workers around the world frantically checking tens of thousands of two-ton bags of nickel — by kicking them, in some instances — to ensure they're the real deal, Bloomberg reported.

The London Metal Exchange — a commodities exchange that deals in metals futures and options — has been advising workers to wear steel toe-capped boots for protection, Bloomberg reported, citing one person who received the instructions.

(It hurts to kick a bag of nickel, you know —the LME itself does not own any warehouses but operates a list of approved storage facilities across the world.)

The mass inspection across the world's warehouses has also involved carefully weighing and scanning the bags, Bloomberg reported. While no other discrepancies have yet been discovered, Bloomberg said, the mystery of what happened to JPMorgan's bags remains unsolved. The firm's nine contracts with the LME have since been invalidated; all of their bags were found to be filled with stones, Bloomberg said.

Access World — the logistics company that manages the warehouse in Rotterdam where JPMorgan's bags were held — is leaning towards the idea that someone snuck into the warehouse and stole the nickel, Bloomberg said. That's because there is a record of the material being weighed when it was first entered into the warehouse, Bloomberg said.

Neither Access World nor the LME immediately responded to Insider's request for a comment.