This is one reason why it is so hard to privatize public functions that are largely "preventive" or "responsive" in nature. New York City used to do this back in the 19th century, and they had to put a stop to it because they ended up with competing fire companies running around setting fires just so they could work more.
It has stabilized the cost of these services and limited the cities liability. Many Southern states have eliminated many of the functions that where always considered government functions. In several areas of TN the local Morgue and Coroners are actually services that are bid out to private companies. The employees are usually paid similar wages, yet they have benefits more in line with the private sector. No excess pension costs and union benefits.
The fire services are NOT a special situation. Remember that a vast majority of all Firefighters in this country are VOLUNTEERS. The future is coming weather the public sector employees like it or not. The idea that 20 - 25 years of work leads to 20 - 30 years of full pay and benefits in retirement are quickly coming to an end.
Read up on the future. This is just one of the companies that are taking up the slack created by the bloated fire fighter unions.