DONORA, Penn. -- In October 1948, a heavy blanket of smog settled on Donora, Washington County killing 20 people and sickening 6,000 others.

Now residents of Donora want to make sure the incident is never forgotten. Loretta Manus, a former Donora resident, saidr she emembers that day, “We couldn't see our hands in front of our faces. We would look down and see our feet so we wouldn't walk on anybody else."

Manus remembered marching in a daytime Halloween parade in Donora 60 years ago when the thick smog made it look like night time.

On Monday, she and many others turned out for the opening of the Donora Smog Museum.

Jerry Simmons, a former Donora resident said, “I vividly remember coming across the Donora bridge and I couldn't see Donora."

The museum is a tribute to the smog victims and was put together by local organizers with the help of California University of Pennsylvania.

Pictures show many of people living in Donora at the time and the incredible darkness that came over the area.

The smog was caused by an air inversion, which trapped chemicals and dust from the Donora Zinc Works in the air.

That event led to many of the clean-air standards now in place in the Pittsburgh area.

Donora resident Don Pavelco said,”Donora was the beginning of the environmental movement, until Donora happened there was no environmental movement."

Dr. Devra Davis, director of the Environmental Oncology Center at the University of Pittsburgh Cancer Institute and a professor of epidemiology at the University of Pittsburgh's Graduate School of Public Health, wrote a book about that incident.

The book, When Smoke Ran Like Water, Tales of Environmental Deception and the Battle Against Pollution, chronicles the disaster and its lasting health effects on many who lived through the event.

Davis has a personal tie to Donora. Her family lived in Donora and survived those five deadly days.

The disaster will also get some national attention on Nov. 2 when the Weather Channel airs "When Weather Changed History," the story of the Donora Smog.

Click here for more information on Dr. Davis and the Environmental Oncology Center at the University of Pittsburgh Cancer Institute