Opening the windows for fresh air, even if you have a window screen, may be putting children in harm’s way.

Researchers at the University of Washington are cautioning against opening a window more than 4 inches, as it may allow for children to fall out.

It is important to know that window screens do not stop children from falling out, so everyone should be cautious. Always check to make sure your windows aren’t open more than 4 inches, which is around the size of a standard credit card.

Using a “window stop” can be a helpful tool, as it can stop a window from opening past a certain amount when placed above the frame.

As you open your windows this summer, be sure to leave enough room for fresh air but not enough for a child.