000 – No response needed, inform Frederick Air
7 to 24 ppm – Hush alarm, monitor closely and inform Frederick Air
25 to 49 ppm – Hush alarm, open windows and immediately call Frederick Air
50 to 70 ppm – Hush alarm, immediately call Frederick Air, watch display closely
If display rises to 90 ppm, call 911, exit at once & move to fresh air.