When should repeat welding fume testing be scheduled after control improvements?

Repeat testing should be scheduled once new control measures have been fully implemented and are being used consistently. This allows you to verify that the changes have actually reduced exposure.

In practice, this is often within a few weeks of installing new LEV systems or introducing new working procedures. Testing too soon — before staff are familiar with the controls — may give misleading results.

If results show exposures comfortably below limits, routine periodic monitoring may be sufficient. However, if results are borderline, more frequent review may be needed.

It’s important to remember that control improvements should always be validated with data, not assumptions.