The number of foggers needed for pest control depends on the size of the space to be treated, as stated for safety reasons on the instructions supplied with the devices.
The fog may contain flammable gases, leading to a danger of explosion if a fogger is used in a building with a pilot light or other naked flame.
[1] Total release foggers (TRFs) (also called "bug bombs") are used to kill cockroaches, fleas, and flying insects by filling an area with insecticide.
Pyrethroids are a class of synthetic insecticides that are chemically similar to natural pyrethrins and have low potential for systemic toxicity in mammals.
Signs and symptoms of pyrethroid toxicity include abnormal skin sensation (e.g., burning, itching, tingling, and numbness), dizziness, salivation, headache, fatigue, vomiting, diarrhea, seizure, irritability to sound and touch, and other central nervous system effects.