Can't see much of a hazard if you go up on the roof, Its apparent you won't be able to step or walk up the Solar Panel. If your working near them then you might get a glare from the sun as a reflection off the glass But if your secure on your scaffold or whatever, that should pose a problem.

There was an issue a few years back where pedestrians were injured when about 6 inch of snow fell from the roof where the solar panels were fitted, send about an area of 30 ft x 20ft of snow 6 inches deep on top of two people who way on their way to the shops, so not sure if the solar panels owners would have to get some sort of Insurance or fit something up at gutter level to prevent the snow sliding off the smooth panels.

OK, are you thinking of physical or electrical hazards.
The physical hazards are obvious, they are there to fall into! ;)
Reflection glare has already been mentioned.

IF correctly installed:
They should be rigid and static.
There should be no electrical risk as there should be no exposed conductive parts.
They should be self-supporting, thus in no danger of collapse.

What concerns do your people have?
What work are they undertaking near these panels?

Remember that there is a statute law requirement that they are installed in compliance with CDM, which mandates that the requirement any subsequent maintenance is “enabled”, thus there is a statute law duty for them to be safe to work on and around.
If they are not safe to work around then someone has committed a criminal offence…
Ignorance of the law is not a defence & all that!

Please expand more on your concerns.

One risk with PV is that they continue to generate power during daylight and the electrical cables remain live with DC current up to the isolation switch. There are normally two isolation switches, one as close to the panels as possible and one close to the inverter.

Unlike a lot of electrical circuits if you receive an electrical shock from this cable it will not trip out. Depending on how the panels are wired this can result in a significant current but even a single panel will produce 12v which while very unlikely to kill you directly will give you a nasty continues shock. An electrical test during periodic maintenance should detect any issue with the cables however there remains the risk of accidental damage.

Alfa,
One would not feel 12V dc as there is inadequate potential difference to drive the current through the resistance of the body, 12V is generally considered safe.
Remember one can touch both terminals of a car battery and feel nothing, a typical lead acid car battery is capable of delivering several hundred amps instantaneously to drive the starter motor, however the PD is inadequate to drive this through a human being.
Well almost all, there will probably be a few in the population who will sense it, but in general and in the standards and models 12V is considered safe.

Any accidental damage must be immediately reported though.

Yes the panels do generate at all times when they have enough light, and they can generate under certain artificial light conditions, and even on a VERY strong clear moonlit night, but obviously at a lower level.

I would be more concerned about strings, noting that there is the potential for some strings on the dc side to reach 1kV, yes 1kV.
However, as the equipment will have been competently installed, inspected & tested, it will be fundamentally safe, and the 1kV will be no more dangerous than any other electrical supply.
That is always providing it was correctly and competently installed etc.!