Expert: Dr. Henry Boyter, Jr. - 4/28/2004

Question
    While investigating the cause of a CO alarm, the highest levels were found to be in an area where a bank of batteries had apparently been overcharged. Acid was bubbling from around the top of the batteries. (I never knew of an association between Sulfuric Acid the production of CO.)
    A Google search produced references to CO being produced when Sulfuric Acid reacts with Formic Acid, as well as with (I believe it was) Carboxylic Acid.
    What would explain the release of CO in this situation? This took place late at night in the hold of an old submarine being used as a museum.

Answer
What you may be seeing is that your alarm is sensitive to other sources. This is common among CO alarms and can be due to the presence of other gases such as ammonia.  High or low temperatures and high or low humidity can set them off.  During battery recharging hydrogen can be produced and that may set it off.  Look at your owners manual for sources of false alarms.  The bubbling you saw was probably the hydrogen which is a big problem itself in a closed space due to poisoning and flammability.