Which of the following statements about batteries is true?

• A. They contain lead and sulfuric acid and can emit hydrogen gas
• B. They contain copper and nickel and emit oxygen
• C. They are always safe to handle without precautions
• D. They only emit inert gases

Answer: (A)

Lead-acid batteries, which are common on fire apparatus, are made with lead plates and sulfuric acid as the electrolyte. When these batteries are charged, the chemical reaction can generate hydrogen gas. Hydrogen is highly flammable and can form explosive mixes in confined spaces, so adequate ventilation and suppression of ignition sources are essential during charging and maintenance. The sulfuric acid electrolyte is corrosive, posing chemical burn risks if the battery case is compromised or handled improperly, which is why precautions are always needed.

This statement is true because it directly reflects the typical composition of these batteries and the gas they can emit under charging conditions. The other statements aren’t accurate descriptions of standard batteries: they don’t rely on copper and nickel as the primary materials, they don’t routinely emit oxygen as a general rule, and they are not safe to handle without precautions due to the acid and potential gas release.