[thackney]

Hydraulic fracturing was first used in 1947.

Pneumatic fracturing goes back to the 1860’s.

[Sea Parrot]

As I stated, hydraulic fracking dates back to the 1920s, and it was developed by Standard Oil Co. (they also developed directional drilling at about the same time)

https://www.google.com/#hl=en&gs_nf=1&gs_mss=hydraulic%20fracking%20w&tok=_QhhiiWfaIYnccvP5YNx-A&pq=when%20was%20fracking%20first%20used&cp=47&gs_id=aw&xhr=t&q=hydraulic+fracking+was+first+tried+in+the+1920s&pf=p&sclient=psy-ab&oq=hydraulic+fracking+was+first+tried+in+the+1920s&aq=f&aqi=&aql=&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=b6d0dfd8395358a8&biw=960&bih=461

The pneumatic fracking you refer to, today would likely be liquid nitrogen fracking, IIRC, the nitrogen is mixed with small amounts of water to create a foam. Some propane fracking has been done, but it is not as efficient as other methods of fracking. IMO and from experience, condensate frac jobs are the most dangerous, due to having so much highly flammable liquids stored in frac tanks on location.