As part of a clear and careful analysis, a prudent safety professional should identify the possible defenses that may be available as well as the probability of success for each defense. As identified in this chapter, safety professionals should be aware that not all defenses are available in every circumstance, and some defenses may be more viable than others. There are a number of defenses that may be applicable to any given situation. The main defenses tend to fall into four basic categories, namely, (1) constitutional challenges, (2) denial of the violation of the standard, (3) challenging the standard, and (4) challenging the process of the citation. Although there may be other defenses available depending on the circumstances, most defenses fall within one or more of these categories.