Minor correction - it was not water/meth injection on JT9's. It was pure demineralised water only. Water/meth was used in piston engine ADI systems. Jets I am familiar with used demin water only and lots of it. Any water not used on TO had to be dumped to stop it freezing.
I seem to recall a BAC1-11 crashed on TO because someone put something other than water it the injection tank resulting in a dual engine failure.