LO cooler damaged by incorrect cleaning agent

What happened

ME LO cooler (Plate type cooler) plates damaged during cleaning.
The vessel carried out the routine cleaning of the Main Engine Lube oil cooler using a pneumatic pump and circulating water mixed with a chemical (DESCALER LIQUID 555) on the freshwater side.
Upon completion of in-situ cleaning during leak test found the plates were leaking. The cooler was disassembled for inspection. Several pinholes on the surface of the plates were noted and all the plates were damaged beyond repair.

Root cause

The plate material was SUS304 (stainless steel). As per the MSDS, it clearly mentions that DESCALER LIQUID 555 should not be used as a cleaning agent for stainless steel surfaces.

Corrective actions

1. Proper toolbox instructions to be given prior carrying out a job.
   
   
2. Relevant pages of maintenance manuals to be read and understood.
   
3. Where applicable, a product data and MSDS sheets should be reviewed prior use.