A fire service spokesman said the extra resources had been sent to the scene given the substance which was found to be leaking.
St John ambulance had also been on site but no one was affected by the substance.
The damaged drum has now been removed from the shipping container and has been put into a specialised hazardous chemical container for disposal.
A port spokeswoman said the small amount of Methyl Ethyl Ketone that did leak is believed to have evaporated.
"Another 10 drums are yet to be removed from the container and washed before being sent on to the owner."
Napier Port chief executive, Garth Cowie, said he was happy with the way Napier Port and support agencies responded, including New Zealand Fire Service and Hawke's Bay Regional Council.
A port spokeswoman said it is expected the clean-up will be concluded within an hour.