I have an old Strablitz 3000BA flash from the early 90's.
Someone told me that it is not safe to use on my 60D.
Said it may blow up my camera.
I've used it once for some hockey games.
What might the issue be?
You're safe... the 60D's sync circuit accepts a trigger voltage of up to 250V. Your Starblitz's is < 40V. "Someone" warned you because there are some legacy flashes with a trigger voltage of up to 400V, which would fry the camera's circuit.
Here's an attestor you can trust, scroll down to the bottom of the page:
www.heritagecameras.co.uk/powerful-bounce-auto-manual-flash-for-hot-shoe-fujifilm-fuji-s9500-s9600-or-many-manual-slrs-2875-p.asp