Full title: A 44-year-old man went to the hospital after pus began oozing from his chest, where doctors discovered a knife that had been embedded in his body for eight years. According to the report, he showed no signs of chest pain, breathing problems, coughing, or fever, and was otherwise in good health.

I wonder if this rather specific question about being a machinist is particularly a US phenomenon.
I’ve only ever been asked if I have the typicals. “Any metallic items on or in your body such as piercings, jewelry, surgical implants?”
The questions never pertained to occupation, let alone being a machinist or involved with metalwork.
Perhaps the question is geared to cover as many bases as possible to reduce the legal attack surface for a malpractice lawsuit. The US is a notoriously litigant landscape when it comes to personal injury.
They asked me of I had welded or done metalwork. I had my head X-ray to make sure there wasn’t any metal in my eyes.
I’ve had metal in them before so it ease worth checking and they definitely asked first.