an h2s hazard relay has been latched the h2s hazard relay is a conventional latch relay that is latched whenever h2s monitor senses that the concentration of h2s 58 exceeds the allowable limit similarly block 112 commands transmitter 32 to transmit fault signal 46 if an h2s fault relay has been latched the h2s fault relay is a conventional latch relay that is latched whenever controller 40 determines that a malfunction has occurred with h2s monitor 22 the malfunction could simply be the h2s monitor switching over to its backup power supply 26 after block 112 or if inquiry signal 108 has not been received the logic transfers to decision block 114 block 114 determines whether a fault exists with h2s monitor 22 if so block 116 latches the h2s fault relay otherwise block 118 ensures that the fault relay is unlatched next decision block 120 determines whether the h2s hazard relay is latched if latched the logic transfers to a decision block 122 which determines whether system 10 is reset if system 10 has not been reset block 122 returns the logic to block 106 otherwise block 122 directs the logic to blocks 124 126 and 128 which respectively unlatches the h2s hazard relay resets a time delay and stops alarm 28 after block 128 the logic returns to block 106 referring back to decision block 120 if the h2s hazard relay is not latched a decision block 130 determines whether h2s monitor 22 detects a concentration of hydrogen sulfide that exceeds an allowable limit if the hydrogen sulfide does not exceed the limit the control logic returns to block 106 if however the hydrogen sulfide does exceed the allowable limit.