A new plating machine had been installed and was being checked for proper operation. During this check, it was discovered that the bearings on the caustic solution circulating pump were defective and had to be replaced. The pump was removed and repaired and was being reinstalled. An electrician was assigned to make the electrical connections, while a plumber performed the necessary pipe connections on the same pump.

The electrician finished the assignment except for checking the direction of the shaft rotation. Since the plumber was out of the area, the electrician asked the company representative supplying the equipment if the pump was ready to be tried out. The representative stated that it was. The electrician walked to the end of the plater to start the motor, just as the plumber appeared. The plumber's shouts to the electrician not to start the pump were too late—the pump had already been turned on. At that moment, hot caustic solution showered out of the pipe flange, which had not been tightened after reassembly. The solution splashed onto the plumber, two engineers in the area, another plant engineering employee, and the vendor representative. The plumber received burns requiring immediate hospitalization and was off work for about two months. One engineer required subsequent hospitalization for eye burns and was off work for more than one week. The other three involved received minor burns.

What would you recommend for contact and post-contact control?