Fire officials say the blaze was reported around 3:30 a.m. Wednesday by police and quickly spread, at one point spewing flames about 30 feet high.
Assistance fire Chief Lee Laubach tells The Morning Call of Allentown the fire was just feet away from the homes when firefighters got control of the blaze.
Evacuated residents of five houses and an apartment building were able to return to their homes by 6 a.m. The cause of the fire is under investigation.
Laubach says dry conditions could make even errantly discarded cigarettes a serious fire danger.