Thinking in terms of processes
Secondary emissions do not occur during the actual processing itself, but afterward. They arise when deposited substances are released again—for example, through cleaning, maintenance, air movement, or the restarting of equipment. Precisely because they are not part of the “main process,” they are often overlooked. Yet they are frequently finer, more homogeneous, and more critical than the original emissions. Those who consider risks only at the point of origin overlook their secondary effects.
What are secondary emissions?
Secondary emissions are releases of substances that are not caused directly by the process itself, but by subsequent events.
Typical triggers:
Important: The substances were already present—they are being mobilized again.
Why secondary emissions can be more critical than primary emissions
What settles changes.
Secondary emissions often occur outside the actual process area—where protective measures are less effective.
Secondary emissions as a common risk
Secondary emissions are not a hazard category in their own right, but rather an aggravating factor:
The focus is on the process—not on what happens in between. Cleaning is considered a “downstream” activity, downtime is deemed “risk-free,” and maintenance is treated as a separate organizational function or involves shifting responsibilities. Secondary emissions occur precisely during these transitions.