Final answer:
The floor lining for explosives must not include dry-cleaning solvent, outdated fire extinguisher materials, or foaming plastics due to the risk of ignition or contributing to a fire.
Step-by-step explanation:
The floor lining for explosives is a critical component in the safety infrastructure for handling and storing explosive materials. It is imperative that materials used for this purpose do not contribute to the potential for accidental ignition or exacerbation of a fire.
Crucially, dry-cleaning solvent and certain types of fire extinguishers are incompatible with these safety measures. Historically, specific fire extinguishers that used chemicals now deemed unsafe have been used, and as such, it's essential that current practices exclude the use of these older methods. Furthermore, foaming plastics are unsuitable for use in floor linings for explosive environments due to their flammability and potential to degrade into hazardous by-products when exposed to heat or fire.
The question is about the floor lining for explosives and what substances it should not contain. In the given reference, it states that the floor lining should not contain dry-cleaning solvent, fire extinguisher systems, and foaming plastics. These substances are not recommended for use as they can react with the explosives or pose a fire hazard.