Level 4 includes the material that are extremely hazardous to health. Inhalation, skin contact , swallowing , Injection, etc. are required full protection gear so that none of our skin surface is exposed because these main routes of entry.
There are different ways a person can come into the contact with hazardous chemicals , which is known as expose pathways. And all these are the basic exposure pathways- inhalation, ingestion and skin contact.
There are four levels or the category of toxicity.Toxicity is define as the concentration or the amount of a particular agent that reaches a target organism, system or population in a specific frequency for a fixed duration.
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