When this plant was first set up as a kosher facility, it was known that they had a non-kosher plant that produces assorted products on the same campus. Of course, the issue of steam return condensate was brought up. It turned out that condensation from the non-kosher factory was not being returned to the boiler so there was no problem to certify the kosher division.
The condensate issue was brought up from time to time when RC’s would visit this factory and is reviewed during my inspections.
During my recent visit, I inquired about the condensate return from the non-kosher plant. It turned out that since my last visit (and not before), the company decided to return the condensate to the boiler, because: 1) since the steam system was heating the non-kosher plant all year, it would be a waste of energy and money to dump the condensate; 2) steam was heating kettles to cook non-kosher icing.
We rectified the problem by requiring the condensate return be dumped and I locked the necessary valve to prevent its return.
Within the next coming month, the company will cut the steam return directly at the cooking kettles so the steam from the heating system (from the effectively kosher parts of the plant) can be returned accomplishing the original goal for the majority of the plant.
In conclusion, issues like this should be constantly reviewed with the company. In this instance, the mistake was caught early enough that major kashrus issues would not be involved.