He is not the only but beyond doubt was the first one. According to Ball lightnings in Tesla's lab:
The adjustments should be made with particular care when the transmitter is one of great power, not only on accout of economy, but also in order to avoid danger. I have shown that it is practicable to produce in a resonating circuit as E A B B’ D immense electrical activities, measured by tens and even hundreds of thousands of horse-power, and in such case, if the points of maximum pressure should be shifted below the terminal D, along coil B, a ball of fire might break out and destroy the support F or anything else in the way. For the better appreciation of the nature of this danger it should be stated, that the destructive action may take place with inconceivable violence. This will cease to be surprising when it is born in mind, that the entire energy accumulated in the excited circuit, instead of requiring, as under normal working conditions, one quarter of the period or more for its transformation from static to kinetic form, may spend itself in an incomparably smaller interval of time, at a rate on many millions of horse power. The accident is apt to occur when, the transmitting circuit being strongly excited, the impressed oscillations upon it are caused, in any manner more or less sudden, to be more rapid than the free oscillations. It is therefore advisable to begin the adjustments with feeble and somewhat slower impressed oscillations, strengthening and quickening them gradually, until the apparatus has been brought under perfect control. To increase the safety, I provide on a convenient place, preferably on terminal D, one or more elments or plates either of somewhat smaller radius of curvature or protruding more or less beyond the others (in wich case they may be of larger radius of curvature) so that, should the pressure rise to a value, beyond wich it is not desired to go, the powerful discharge may dart out there and lose itself harmlessly in the air. Such a plate, performing a function similar to that of a safety valve on a high pressure reservoir, is indicated at V.
Nikola Tesla: US1,119,732. Apparatus for transmitting electrical energy, Jan. 18, 1902.