The most common ones are the compliance audits. This is where you go and check to see if you are in compliance with the various environmental regulations. You often do this with a checklist. You are asking the question: “Is everything OK today?” This type of audit gives you a snap shot of your compliance status on the day you perform it. It does not tell you anything about what happens a week or a month later.
With the checklist, you are essentially asking yes/no questions. For example, you are asking “Is the accumulation start date clearly marked on the hazardous waste label?” There can be only two answers. It is either “yes, it is there” or “no, it is not there”.
The second type of audit is the environmental management audit. Here you do NOT ask yes/no questions. You ask open-ended questions. For example, you would ask the person responsible for the waste accumulation area this type of question: “When do you put the accumulation start date on the label?” He cannot answer yes or no to your question. If he answers “when I ship the container out”, that would be the wrong answer. The correct answer is “when the first drop of waste goes into the container in the storage area”.
When you ask open-ended questions like the example above, you are trying to determine the level of understanding and knowledge of the person who is responsible for managing the wastes. You are not asking the “is anything wrong here today” question. You are not taking a snap shot. You are trying to determine how that person will manage an environmental problem when it comes up a month later.
In a compliance audit, you are looking at physical things like evidence of spills, records, labels, etc. In a management audit, you are looking at people skills.
By the way, a tell tale sign of future problem is when you ask someone “why do you do it this way” and the reply is “I am not sure but we have always done it this way.”
It is all in how you ask the right questions.