A lot of times this can just be from dust buildup on/around that nozzle (I'm almost sure that's not the proper terminology tho). An easy thing to try is shutting off the gas to the insert and taking a can of compressed air to that nozzle and everything around it. If you can easily take off the panel in front of it, even better, spray all the dust out you can.

Is this dangerous?

The hissing noise is not. Turning your pilot knob to some in-between setting is.