In theatrical productions, the health and safety of actors and crew often depend on what?

The health and safety of actors and crew relies on lightweight set pieces in theatrical productions. Light weight materials were use so nobody will experience bumps or bruises especially on the heavy action part. 

Moreover, during the production, everyone is required to be healthy in the set for everybody have more than one job. All actors and crew must be ready with the different pace of the scenes so their minds are set on what to do and avoid unnecessary stress.

and after water is usually warmed by the sun the water temperature raises and then evaporates .