HAPPY VALLEY, Ore. -- Emergency workers issued a warning Wednesday after an 18-month-old child survived a three-story fall from an apartment window.

Since the beginning of July, six children have fallen from upper-floor windows in the Portland-Salem area. Officials said unattended children are pushing through the screens of windows that have been left open due to summer heat.

Read More: Toddler Survives Fall From Third-Story Window

On Wednesday, Nicholas Enriques plummeted 24 feet after pushing through the screen of a Happy Valley apartment. A maintenance worker at the complex heard a thump on the ground nearby and realized the child fell. The worker called 911 and an emergency crew responded to take the boy to Oregon Health & Science University hospital.

The hospital said the boy is in good condition, but other children were hurt far worse in recent window falls.

Earlier this summer, a 2-year-old Canby boy fell head-first onto a concrete patio. He survived, but was badly hurt.

Clackamas firefighter Steve McAdoo said a simple window lock can keep children safe but still allow a cool breeze into your home.

"If you have kids in your house and they are able to access windows, it's a very simple, inexpensive item to keep them from falling through," McAdoo said.

The locks can be purchased at any local hardware store.

Summer Heat Leads To More Child Window Accidents