Rensselaer Fire Chief Bill Hummel resigned Wednesday just hours before volunteer firfighters are set to bring concerns about training and proper equipment to city officials. City volunteer firefighters and county officials say both the chief and an assistant chief have stepped down. While the mayor and the chief have not returned calls for comment, the volunteers believe the resignations are a direct response to growing tensions between volunteers and career firefighters within the city. Michael Stammel is the chairman of the county legislature and a volunteer firefighter for many years. He and others say flaws within the system have recently come to light that show a huge breakdown in communication between Hummel, the volunteers, and paid firefighters. Stammel also says volunteers have not been given necessary training or proper equipment to respond to emergencies.