The Food and Drug Administration (FDA) ensures that carbonated soft drinks are safe, sanitary, and honestly labeled. In fact, FDA has established Current Good Manufacturing Practices (CGMPs) for carbonated soft drinks, which describe the basic steps manufacturers and distributors must follow to make sure carbonated soft drinks are safe.
From FDA Website:
Additives and Contact Substances
Only food and color additives that are determined to be safe, based on scientific information available to FDA, may be used in carbonated soft drinks. For example, this might include additives such as citric acid as a flavoring or a preservative, or caramel coloring. Food contact substances - the materials the carbonated soft drink "comes in contact with," such as the bottles and cans in which it is sold; also are strictly regulated for safety.
The Nutrition Facts Panel on carbonated soft drinks typically includes the serving size and the nutrients provided in a serving: calories, total fat, sodium, total carbohydrate, sugars (if present), and protein. If a nutrient content claim, such as "Very Low Sodium," appears on the label, the manufacturer must also add the statement "Not a significant source of ________," with the blank filled in by the names of nutrients that are present only at insignificant levels.
Click on FDA for more information about carbonated drinks.