"Airplane Fire Safety Debate Rekindled"
You might find this source useful. The citation is Science "Airplane Fire Safety Debate Rekindled", by Marjorie Sun, Vol. 221, No. 4605 (Jul. 1, 1983), pp. 35-36.
A long article on the subject includes, for example, this statement"
"The FAA has also not yet required aircraft manufacturers to place exit lights near the floor. In 1972, the safety board urged such a regulation based on the obvious fact that smoke rises and obscures the exit lights near the ceiling."
and others (copyright precludes pasting it all here). While not directly answering your question, it does provide some interesting background on the length of time the debate had been going on before the requirement was finally mandated.