According to new research, stainless steel sinks could provide a breeding ground for Legionnaire’s disease bacteria, more so than porcelain or copper sinks.

The issue arises when the coating commonly applied to all stainless steel surfaces starts to degrade, creating an ideal breeding ground for the potentially deadly disease.

In a study overseen by Wilco van der Lugt, a safety engineer with expertise in Legionnaires’ prevention, a team of researchers tested water with and without the Legionella Anisa bacteria after it ran through a variety of different water tap systems.

The stainless steel tap system provided the most fertile ground for the disease to survive, with 50% of all tests turning up positive for Legionnaire’s disease. The degradation of the protective coating on the stainless steel fixtures led to rust, and rust allows the Legionella Anisa bacteria to multiply.