Dive summary:

• Hydrogen atoms get into nano-scale cracks that occur as metal shifts under stress, and they get in the way of the metal's atomic-level mechanism for handling stress, according to scientists in Canada and Switzerland. The result is brittle metals over time.
• The researchers at McGill University and the Institute of Mechanical Engineering at Ecole Polytechnique Federale de Lausanne report that they have developed a computer model that accurately predicts what will happen to metals in tests.
• The new understanding will help in designing materials that are less susceptible to hydrogen's effects and better retain the ductility and toughness that make metal desirable.

From the article:

Hydrogen, the lightest element, can easily dissolve and migrate within metals to make these otherwise ductile materials brittle and substantially more prone to failures. ...