This is an issue United Nations Secretary-General Antonio Guterres has also raised.
He was specifically concerned about the nuclear waste facilities in the Marshall Islands and called it "a kind of coffin" which has health consequences to the locals.
PIF leaders are calling on the United States – the country responsible for the testing – to "increase its monitoring and to address health consequences related to the nuclear testing programme, conducted in the 50s and early 60s".
The communique document was released after midnight, some two and a half hours after the leaders' forum had wrapped up.
Media were told a communique and a declaration has been agreed but Pacific leaders would not say what had actually been achieved.
Morrison said he would not "jump the gun" as to what was actually signed but stressed there had been compromise.
Ardern was also reluctant to comment any detail, opting to not discuss the outcome until the statement until it had been released.
That meant no specific questions about the document could be asked of her, or Morrison.
But Ardern said it was a "good and robust" debate.
"I think everyone in the room expected it would take some time; we have been discussing some of the most substantive issues for the Pacific and that did include climate change."
But she did say that there would have been some members of PIF who would have wanted to go further, and those which would have preferred to pull back.
"Compromise is not new and I think you'll see there has been compromise in these statements – I think it's fair to say that there has been compromise by all parties."