An idiom meaning something is out of control or unmanageable — there is nothing one can do to deal with it.
このプロジェクトは手がつけられないほど混乱している。
This project is so chaotic it's impossible to handle.
台風の被害で庭の木が手がつけられない状態だ。
After the typhoon damage, the trees in the garden are in an unmanageable state.
彼は酒癖が悪くて家族も手がつけられない。
His drinking habits are so bad that even his family can't handle him.
子どもたちが暴れていて、先生一人では手がつけられない。
The children are misbehaving so much that one teacher can't control them.