Instantiate with Toggle

Unity Engine
1

I have this code which I use to instantiate a splurge of gas on a surface. It works the first time round, but when I toggle the gas OFF and then turn it ON again, I am no longer able to instantiate. Can anyone tell me why please?

createToggle = GUI.Toggle(Rect(115,390,110,30), createToggle, "GAS", "button");
         creategas = createToggle;
            if (creategas)             
            {
            while (gasNumber <= 1.0) {  
            gasInstance = Instantiate(gasmaker);
            gasNumber++;
            }    
            } 
            else 
            { 
              var gas = GameObject.FindGameObjectsWithTag("gas");
              for (var i in gas) {
              Destroy(i); 
            } 
    	}
2

Are the gas launchers particles systems? If so, you can just enable the autodestruct option on the particle animator to handle destroying objects for you. If not, then is the gasMaker object a prefab or an object in the scene? If it’s a scene object, could you be picking it up with the FindGameObjectsWithTag call and destroying it by mistake?