Chronic health effects caused by exposure to hazardous substances often are:

Chronic health effects resulting from exposure to hazardous substances are often characterized as irreversible. This means that the effects can lead to long-lasting damage that does not improve over time or can result in permanent changes in health status. For example, long-term exposure to toxic chemicals can lead to conditions such as cancer, organ damage, or neurological disorders, which cannot be fully healed or reversed once they have developed.

In contrast, temporary effects would suggest that the health issues resolve once exposure ceases, and reversible effects imply that the body can heal after the influence of the hazardous substance is removed. However, chronic exposure typically leads to sustained health consequences that endure after exposure, highlighting the importance of recognizing and mitigating risks associated with such substances. Unknown effects refer to uncertainties regarding the health impacts of certain exposures but do not accurately describe the chronic nature of well-documented hazardous exposure outcomes.