who is to blame vs. who is to be blamed

I came across a sentence like that: “I don’t want to get involved in a lengthy argument about who is to be blame”. I think it should be “I don’t want to get involved in a lengthy argument about who is to be blamED”. Could you please tell me your opinion? Many thanks.

I don’t want to get involved in a lengthy argument about who is to [b]be blame.[/s] – would be the correct option.

I don’t want to get involved in a lengthy argument about who is to be blamed, – would only work if you were deciding who to blame at a future point.

I don’t want to get involved in a lengthy argument about who is to be blame. – the original is wrong in all cases.

Hi, Beeeneees. Very nice to meet you for the first time on the forum.
Please give me more clarification about your comments.

In the sentence “I don’t want to get involved in a lengthy argument about who is to BE BLAMED” -> I understand that “WHO” here would receive blame, 'coz I base on passive structure of the verb “blame”. Is it right?

And " … about who IS TO blame" that means WHO here would blame somebody else, 'cos I suppose “IS TO” used to express an future action.

Please do not laugh at me if I make confusion.
Thanks a lot.

In both structures ‘who’ would receive the blame.

Why both? I still don’t understand as in case of “IS TO blame”, 'coz its subject would do action. In other words, the subject would “blame” actively, I think so.
Do you mind explaining further? Thank you.

This is an idiomatic expression:

‘be to blame’ for something

It is not the same as the standard use of the verb ‘to blame’. If that were the meaning here then the sentence would read, “Who is blaming…”

Please see the first point under ‘idioms’ here:
oxfordadvancedlearnersdictio … me#blame_1

Thank Beeeneees a lot for very useful website for learning English.
Cheers.