According to safety regulations, what is the recommended method to neutralize a formaldehyde spill?

To effectively neutralize a formaldehyde spill, the use of ammonia is appropriate because it reacts chemically with formaldehyde to neutralize its hazardous properties. Ammonia can transform formaldehyde into less harmful substances, making it a suitable agent for managing spills safely. After applying the ammonia, it is crucial to wipe up the area to remove any residues of the spill, ensuring that the space is safe for further use.

The other methods listed are not effective or safe. For example, simply adding water may spread the formaldehyde rather than neutralize it, which can exacerbate the danger posed by the chemical. Similarly, using vinegar does not effectively neutralize formaldehyde; while vinegar is an acid, it does not produce a safe or non-toxic reaction with formaldehyde. Leaving a formaldehyde spill to air dry is also unsafe, as it allows harmful vapors to linger in the environment, posing health risks. Therefore, utilizing ammonia to neutralize formaldehyde is the most effective and recommended approach in line with safety regulations.