The AP4C is a portable chemical contamination control device used to detect directly chemical agents in the form of vapor, aerosols, dust and with the S4PE in the form of liquid. AP4C detects compounds of phosphorus (such as all G, V agents: GA, GB, GD, GE, GF, VE, VX), compounds of sulfur (such as H, HD, HL agents, Arsenic compounds (contained in L, SA, DM) and other gases such as Ammonia, Cyanogen chloride, Cyahydric Acid, etc. as well as all the precursors of the above chemicals. The high sensitivity and fast response time make the AP4C especially suitable to check up contamination.