Update at 7:08 p.m. Friday: Wreckage has been removed and traffic moving again south of Houston, officials said.
Posted at 6:44 p.m. Friday: An accident south of Houston has slowed traffic on U.S. 63, authorities said.
It occurred near Oakdale Road and U.S. 63 and blocked one lane of traffic. Numerous agencies are on the scene.
This is a developing story.