In this paper we will design a system that will detect a number of toxic gases in our life, such as carbon monoxide CO, CO2, methane, butane, H2, LPG, smoke or profane, benzene CNG gas, NOx, ammonia sulfide benzene vapor gas, flammable gases even an air quality. We will display the details on the screen, and we will use a set of gas sensors for this work and we design a program that monitors and display readings and we will withdraw these gases in the event of leakage and design sound alarm for giving a gas leak warning through an amplification circuit to give high quality designed for this purpose. We will use RFID and Pad key for opening this system and a mechanical door will open when entering the system. This system, which we will design, is an embedded system. It is used in many sensitive plants and nuclear factory. But the idea of this system will be a simpler idea of those systems for simulation of those used in sensitive plants and also gases that we will sense are specific gases because the work required to feel larger gases will be more expensive and more complex and we will need a very large number of sensors to achieve such that system. Finally, do RFID security cards are safe to use and are suitable for this system ?We will learn about these details in this paper.