"It could be taken up by crustaceans like shrimp crabs, things like that which are the base of the food chain and that could be passed up to fish and then mammals and the toxins could be concentrated and that could be harmful to animals that feed on these smaller organisms."

VOA: standard.2010.05.09

Stress is more likely to be harmful if you feel helpless to deal with the problem or situation that causes the stress.

VOA: special.2009.03.24

At least two hundred fifty of them are known to be harmful.

VOA: special.2010.03.09