What occurs to toxic gases as flames spread upward in a fire?

As flames spread upward in a fire, the temperature in the vicinity increases, often leading to the production of various harmful gases through the combustion of materials. As the fire grows, it intensifies the thermal decomposition of materials, which can produce a larger volume of toxic gases such as carbon monoxide, hydrogen cyanide, and other volatile organic compounds. This increase in temperature and the chaotic conditions that accompany a spreading fire facilitate more rapid combustion processes. Consequently, the concentration of these toxic gases can rise significantly, presenting serious risks to anyone in the vicinity. Therefore, the correct response reflects the reality that with the upward spread of flames, the production and presence of toxic gases increase, compounding the hazards associated with the fire.