Can a power adapter give out hazardous voltage
Under no-fault conditions that type of power supply can be assumed to produce 15 volts (plus or minus a small percentage due to build up of tolerances and temperature coefficients). If part of the the voltage regulation circuit failed it could produce a voltage significantly higher than 15 volts and this is where a lot of designs use an independent crow bar circuit to clamp the voltage to an avarage safe limit should a component in the main circuit fail.

I suspect that design has protection against single component fails and uses a crow-bar circuit (as do a lot of designs that are certified CE). Some designs don't but they rely on an extensive analysis of what can happen under single fault/failure conditions.

I expect that if you look in the product data sheet there will be some information about this. As to whether this power supply is suitable for the environment type you wish to use it, read the data sheet.