A pair of incidents that occurred in the Capitol Hill area over the weekend appeared to demonstrate one of the principal concerns that surround exterior fire escapes.

Attached to the outsides of buildings, these arrangements of metal ladders and landings were intended to protect the safety of residents. But many people have warily observed that the escapes can endanger as well as protect.

Apparently they were used over the weekend in their less desirable role. Police said two apartment burglaries were reported in an area of Capitol Hill north of Independence Avenue and between Second and 13th streets. In both, police said, “entry was gained through an apartment window accessed” by fire escape.

In at least one incident, the police said, the apartment window was left unlocked. In the other, police said the resident thought the window was locked.

A police official called on residents to secure their windows properly, “particularly those that can be accessed by way of a fire escape.” It was not clear what was taken in either of the burglaries.

The fire escape dates back to the Civil War era, according to an online posting, and was once considered a vital component of fire safety. However, in recent years, innovations in protection against fire have made them appear less necessary.

Often they are arranged so that when not in use the bottom rung of the bottom ladder is high enough above the sidewalk to prevent easy access from below.