It is important to identify and understand the different operatives in this workplace and their exposures to hundreds of different chemicals and substances. Drilling fluids are complex and vary along with drilling conditions and are broadly divided into oil-based/nonaqueous and water-based drilling fluids. Drilling fluids may be irritant but patch testing can start at 2% and may go as high as 50%. Olefins in drilling fluids can cause severe irritant reactions and may be tested by a ROAT test. Di-ethylene triamine (DETA) and Tri-ethylene tetramine (TETA) are used as emulsifiers in drilling fluids and have been the main cause of outbreaks of allergic contact dermatitis. Bromides particularly calcium bromide may be added to mud, and handling this material can lead to severe chemical burns. In marine placements, epoxy resins are used extensively for rust prevention and subsea equipment.