[adpiucf]

I don't see how this is your fault. Your former boss was fully accountable. You even asked him and relied on his answer that no permits were needed. He failed you and failed the client.

I understand that you're the only one left... but part of the beauty of former employees is that they become the scapegoat (whether they deserve it or not) when the time comes to assign blame.

Instead of fishing of fishing for an old email, brainstorm some possible solutions before you speak to your current boss.

Go to your current boss. Tell her the situation, apologize and ask what you can do together as a team to mitigate the damage. You current boss should be the one to take full accountability for this -- she may not have been part of the original decision, but she's your supervisor now and presumably works on this client account. So it is her job to fix it.

If you were to be fired for the mistake of another employee (your old boss), I think you should consult an attorney. You should not be disciplined for doing your due diligence -- consulting with an expert-- relying on their advice and following their directions.

The sooner you communicate this error to your boss, the better you will feel and the sooner everyone can begin to rectify the situation.