Three fires broke out Saturday in household dryers in one Maryland suburban county and a fourth fire related to washing clothes was said to originate in a laundry room, the Montgomery County fire department said.

It was not immediately clear what aspect of dryer operation caused each of the fires. However, county fire department spokesman Pete Piringer said the primary reason for dryer fires is failure to clean them. He noted the importance of frequent cleaning of the lint filter.

Saturday’s dryer fires were reported, according to Piringer, in a single-family house in the 12300 block of Dalewood Drive, an apartment in the 4000 block of Post Gate Terrace, and another apartment in the 3300block of Hewitt Avenue.

The laundry room fire was reported in the 11400 block of Lockwood Drive, Piringer said. It originated in trash, and caused the evacuation of a three-story apartment house, he said.

It appeared that there were no immediate reports of dryer fires on Sunday.