I have just plastered around a double gang outlet and have gotten a lot of plaster around and touching the exposed conductors energizing that outlet. Is the plaster touching all conductors and surrounding the outlet a fire hazard?

I would shut off that circuit and clean off the plaster. Plaster when wet can short the outlet and breaker.

I would shut off that circuit and clean off the plaster. Plaster when wet can short the outlet and breaker.

You mean drywall mud? (plaster is different), best to let it dry as long as it's not causing any problems at this point, then turn it off and clean it out, a lot easier to get it off when dry.

Electrical boxes often used for drywall knife cleaning stations.