Questões de Concurso Público Petrobras 2011 para Engenheiro de Equipamento Júnior - Terminais e Dutos

In replacing the word “if" in the sentence “If petroleum gets into the lungs, it can cause quite a bit of damage to the lungs [including] pneumonitis, or inflammation of the lungs." (lines 57-60), the linking element that would significantly change the meaning expressed in the original is