blame it on the process and fix the process.

If He/She is Manager :- blah blah blah. How you can do this ? Go to hell and fixed it asap.

If He/She is Leader:- The first step to solving any problem is to accept one’s own accountability for creating it.

I've been on both sides of this. Stuff happens. Even the best processes can sometimes fail. Comments here have been pretty spot on. Reviewing what went wrong and actually putting procedures in place to prevent it in the future is about all you can do.

Of course, you said, "due to recklessness". Keep in mind, "recklessness" is completely subjective. A great developer could be under a lot of pressure to get something out the door. Where does that alleged recklessness come from? Just some sort of lapse in judgement? Or, perhaps, working against the clock to get something out the door due to overselling and underestimating on the part of management. Or was it just developer burnout... working long hours to finish a project or fix critical bugs or whatever, and the developer was simply exhausted?

There's a quote from Thomas J Watson, the founder of IBM. I'm not sure how accurate it is, and every time it's quoted the dollar amount seems different - but the principle makes sense:

“Recently, I was asked if I was going to fire an employee who made a mistake that cost the company $600,000. No, I replied, I just spent $600,000 training him. Why would I want somebody to hire his experience?”

— Thomas J Watson

It's a really tough issue, and mistakes happen. Was it a true accident, or was it caused by negligence, over-tiredness, or more preventable reasons? Does the employee care about the consequences of their actions (would they care if it happened again or will this change their behaviour).

It's really hard to say, but I know that by firing them and replacing them you aren't protecting yourself against this happening again! If you want to avoid this happening again, having somebody who knows that the consequences fully mean (like somebody who has made a mistake before) is probably a great person to have in that role because they understand the costs mistakes involve.

My take on it: mistakes are good work experience and education that come at a very high cost and usually at an inconvenient time, but people the whole experience might turn that person (or team) into a more valuable employee if it's something they grow from.

I'd cost my third employer 45k€ in 30 minutes with a wrong database update, I went through all tables and recovered everything when I told him, he saw how anxious I was and just shrugged his shoulders told me the amount and I never wanted to fail like that again ....

Usually the one who screws up blames himself the most.

I agree with Mev-Rael Mitchel Pigsley it's better to build a system to prevent it from happening again.

As a manager, I would think "I just spent 10k to educate this person and to fix a problem in our development process. That's an investment I won't risk ruining by acting irrationally."

Process of "uploading bad code" is not simple, you should do at least code review, manual test and at least some people should care about it, so if you failed at the end, than you failed as a team, all those people who should spend their time in that process and who didn't find anything bad, are responsible together and not just only one person.

After all, like it or not, it is always top level managers mistake because they, their processes, their work or absence of their work allowed it to happen.

Finally, it is absolutely ok to fail. Everyone does mistakes. Business is about making and loosing money all the time. However, if you never do analysis, preventive actions, improve your process and security, then something is really wrong.

How manager should react in such situation depends only on situation itself. Usually some report (why it happened, what can we do to prevent it) and restoring as much damage as possible (for example, moving to a backup or rollback to previous version) is all what manager needs, however, of course, company may just fire a person which is also absolutely a normal situation and in some cases it is even possible to legally get at least part of the money lost back from that person. Professional understands risks more than managers and always takes all the responsibility.

Worst managers are those who say "it's your fault you should remember this and this and this" the good ones say "what can we do to prevent this in the future".

Most people are the first example.