Our three sets of metal stairs are going to be repainted where paint has worn off and I have been instructed to have the nose of the steps painted in a white fluorescent paint as an aid for a visually impaired employee.

I have yet been unable to find a white fluorescent paint, only green or yellow, but my question is does it need to be fire retardant?

No is does not require to be fire retardant and speak to the person requiring the repaint to see if they would accept any light coloured paint, then you could use the green or yellow fluorescent paint.