What is the cost of the fireworks to the city?

[nvidia99999.livejournal.com]

How can one estimate the total cost to the city? Is it possible to get numbers from past years? In the past, I remember hearing that NSTAR and other companies were sponsoring them. But they were not paying for the extra cost of firefighters and cops working overtime, for example. If they cost nothing, I'm all for it. But if they are funded with taxpayer dollars, then I'm more ambivalent, given all the recent budget cuts.

Edit: Information on fireworks cost from other cities: www.cnn.com/2009/US/07/03/independence.day.fireworks.canceled/index.html