Summary: R’ Moshe mentions a chashash sakanah, R’ Tzvi Pesach Frank and R’ Nissim Karelitz do not. When quoting the ??? ???, the ?????? ??? qualifies the he was referring to a case where there is none. It is apparently not assumed that every case of an open gas burner is automatically a sakana.
The ?? ??? gives two, possibly three reasons to be mattir.
1) Rotating a knob is not considered ?????.
2) It is ??? ??????? ?????? ????? ????
3) ??? ?? ???, but he is ????? if it applies where you’re not being ????? the ???.
??? ??? is mattir because of ??? ?? ???, but does assume it’s ?????. It seems he holds it’s ????? ???? ?????, not ??? ??????? ??????, so ????? ???? does not apply.
Bottom line: muttar, but not nearly as pashut as some indicated.