Final answer:
Exposure to hazardous material over an extended time is known as chronic exposure. This often involves prolonged or repeated contact with low levels of a substance, leading to health effects that may not be apparent for many years.
Step-by-step explanation:
Exposure to a hazardous material over several months, years, or decades is known as b) Chronic exposure. This type of exposure involves contact with a substance over a long period, which can lead to health effects that may not be immediately obvious. Examples of chronic exposure include long-term exposure to cigarette smoking, low-level radiation, and moderate alcohol use. Unlike acute effects, which occur shortly after a high-level exposure, chronic effects can be difficult to detect because they develop over time and require consistent or repeated exposure to a contaminant.