I started using them when Harbor Freight's started popping up and selling them in the early 1990's iirc.
Yes, over the early to mid 90s state health and safety agencies were promoting the use of gloves in automotive repair to prevent
skin from absorbing poisonous chemicals in oil, gas, and other fluids. I do remember some tech, very few wearing cloth black grip style gloves that were commonly sold by the tool trucks back in the mid-late 80s. They seemed to disappear in the early 90s and limited techs started wearing the nitrile gloves
in limited numbers but they became common by the early 2000s. I'd say it was standard to wear them by the mid 2000s.