"No test or study can prove that any environmental agent is safe," Dr. Stevens said.

Jirtle has long been interested in how environmental agents influence biological systems.

Possible environmental agents include flavonoids in food, tobacco smoke, and most herbicides.

As for environmental agents, city water is as safe if not safer than what most people drink.

Recorded there are injuries done to it by environmental agents, from noxious chemicals to intense sunlight.

Children must often rely on adults to protect them from toxic environmental agents.

One possible explanation is that the syndrome results from a combination of an environmental agent and a hereditary predisposition.

Mycobacterium and Propionibacteria species have both been suggested as the environmental agent, though the evidence for this is inconclusive.

The model also considered environmental and animal agents.

"But if you dare to kill a caiman and the environmental agents catch you, you're the one who has to pay a fine."