The strength of the magnetic field ranges from 0.5 to 3 Tesla in MRI units used for medical diagnosis. That is a strong magnet!
I doubt that a few coins would kill somebody but there have been deaths associated with small oxygen bottles flying into the bore of the magnet while there was a patient on the table.
A few years ago I attended a course on Magnetic Resonance Imaging and we were shown several examples of MRI accidents such as floor buffer machines and office chairs pulled into the bore. There were a few oxygen bottles too. They showed us how they got one of the oxygen bottles out: by using a Land Rover! They had to attach a rope to the bottle and tow it out. When the bottle was free of the bore of the machine, it remained suspended in mid-air and the rope was fully taut.
Then last year I conducted a few experiments here in London to see whether certain bullets had ferrous properties and therefore could possibly pose a hazard if the patient went for an MR scan. I had to make a special perspex and wood enclosure for the bullets and I ended up crawling into the bore with the test tool and bullets, and my digital camera. I had to hold that camera with both hands because the battery is ferrous. The magnet was so strong that it operated the zoom of the camera without me touching anything. When I got into the mouth of the bore the image turned into a blue snow, it was compressed vertically, and then the camera shut down and could not be powered back on for ten minutes!
I'll see if I can find pics of that.
Stronger magnets of the order of 10 Tesla to 20 Tesla have been used to levitate organic materials. One of the things they have successfully levitated is a small frog. So you can imagine how powerful that magnet is! (But they are't approved for medical use and the bore is very small)
Here is where they levitated the live frog:
http://www.hfml.ru.nl/froglev.html