| No. | End factor | Methods of confirmation | Method of argumentation |
| 1 | Failure of monitoring of water quality by the operator | Inspection of work records and on-site observation | Investigation and analysis |
| 2 | Insufficient staff training | Inspection of employee training records and induction certificates | Investigation and analysis |
| 3 | Delay in emergent chemical feeding | Inspection of work records and on-site observation | Investigation and analysis |
| 4 | Malfunction of chemical feeding valve | On-site confirmation of the chemical feeding valve | On-site verification |
| 5 | Failure to strictly follow the procedures | On-site confirmation of operational procedures | On-site verification |
| 6 | Lack of work instructions | On-site confirmation of the availability of operating instructions | On-site verification |
| 7 | Ambient temperature change | On-site temperature measurement | On-site verification |
| 8 | Lack of deaeration in feed water | On-site collection of relevant data for analysis | Investigation and analysis |
| 9 | Remaining oxygen in the deaerator | On-site collection of relevant data for analysis | Investigation and analysis |