I've had product liability insurance for the USA and Canada previously but the policy changed again last year and I can't for the life of me find anyone who'll do it (for less than lots of 0s at the end in any case).
Weirdly they had given product liability for worldwide when my inventory included body creams, oils and incense ...
So how did you get the client to accept responsibility? Having asked that I had noticed in two quotes that I would have to stop the items going to North America even if they passed from my hands to someone elses ... how on earth you can do that is beyond my ken!
If you are a manufacturer then it will be different, I was sourcing computer products and shipping to the USA, the manufacturer was still liable for product liablity but I was able to clause out our own liability - whether it would have stood up in court is another matter but the clients were happy enough.
Our insurers at the time would not touch electronic components going to USA - I tried many brokers and always got the same answer -"NO" unless it included my first born.
Your best bet would be to find a competent broker and let them do the sourcing for you.