Can't seem to find an OID for the bad blocks percentage. I want to add this to our monitoring system to alert on any failing flash memory so we can replace the devices as soon as any are detected

Nope? There is none?

In that case what is the error message generated in the log file when a bad block is encountered? At least that way I can write a syslog alert when its detected. But I need to write a regex match statement and I don't know what the message is