The Japanese government had pulled some 1.63 million doses of Moderna vaccines after a metallic substance was found in 39 vials in August.
Japan pulls 1.6 million COVID vaccine doses over contamination fear as COVID's spread causes heartache, Paralympic anxiety
It's now come out that the substance has been identified as "stainless steel."
The Latest: Moderna, Japan partner recall 1.6 million doses
Whether the steel is safe or not, it's a reminder that full disclosure of what is in the vaccines may not be happening whether it's through intentional omission or neglect.