The Metro Controller is capable of monitoring up to 250 remote addressable flammable and toxic Metro gas detectors. Together they form the Metro system designed to protect people from flammable and toxic gas hazards commonly found in car parks, tunnels or other areas where automotive vehicles may operate. The Metro Controller provides automatic control of ventilation systems that maintain gas levels at or below a safe level. Where gas levels rise above maximum exposure limits, the Metro system raises alarms to instigate site evacuation. By integrating the gas monitoring systems and ventilation control, not only are harmful gases kept to safe levels but building running costs are also minimized.