Final answer:
Gases released during volcanic activity can be potentially fatal on their own and have harmful effects on the environment and human health.
Step-by-step explanation:
Gases released during volcanic activity can be potentially fatal on their own. One example of this is the 1986 disaster near Lake Nyos in Cameroon where a large volume of carbon dioxide gas was released from the lake, leading to the deaths of more than 1700 people. Additionally, gases released from volcanic eruptions, such as carbon dioxide and sulfur dioxide, can have harmful effects on the environment and human health.