Safety of cockroach killing sprays

Last week, my wife was in the kitchen and suddenly she shouted for help. I ran to her only to see that she is in a state of shock. Later, I was told that the gas burner was lit for cooking. After seeing few cockroaches nearby, she sprayed the killing chemical from the container around the cockroaches. Immediately, the spray caught fire from the gas burner and the flame came towards her. She turned off the burner knob and went into shock. I never thought that spray will be within flammable limits and this taught me a lesson.

Earlier, few years ago, when I sprayed the same chemical for killing cockroaches, over the electrical switch board and also inside the electrical winding section of kitchen mixie and then switched ON the electrical point, the MCB tripped in the house. Without understanding the reason, I set it ON and again switched ON in the kitchen. This time MCBs tripped at home as well as at the LDB in the ground floor of our apartment complex, from where power cables are drawn to my residence. Then, I set it ON. Next, when I switched ON the mixie, there was burning smell from it. Then only it occurred to me that the spray caushed short circuit and lead to tripping of MCBs and coil burning.