What group grew larger as a result of the triangle shirtwaist factory fire?

International Ladies' Garment Workers' Union.

Explanation:

The Triangle Shirtwaist Factory Fire (1911) caused the death of 146 workers, most of whom were women who fall victims of the fire or jumped to their deaths trying to escape. The disaster was caused by faulty safety precautions and absence of fire escapes.

The fire prompted legislation demanding better factory safety criteria and served the growth of the International Ladies' Garment Workers' Union, which worked for better working conditions.

i think its the outcome of people's preferences.