David Chalian's comments were caught on a microphone while he was discussing Hurricane Isaac, which hit Louisiana with the Republican convention under way.
In a video posted on YouTube, the commentators can be heard discussing how Isaac was bearing down on the US Gulf coast.
According to the BBC, as footage is broadcast of Romney and his wife Ann, one voice can be heard saying, 'They're not concerned at all.'
Laughter is heard in the background as Chalian says, 'They are happy to have a party with black people drowning.'
According to the report, Chalian later apologised on his Facebook page for 'making an inappropriate and thoughtless joke'.
A Yahoo! News spokeswoman said that he has been 'terminated effective immediately'.
"We have already reached out to the Romney campaign, and we apologise to Mitt Romney, his staff, their supporters and anyone who was offended," the spokeswoman added.