CFCs were chemicals commonly used in refrigeration and as propellants in aerosol cans. In 1974, a research study discovered that CFCs were leading to a dangerous hole in the ozone layer. By the late 1980s most CFCs were banned as a result of the research.
Answer
A
CFCs were commonly used in refrigeration.
B
CFCs were replaced with other products.
C
CFCs were causing a large hole in the ozone layer.