Which precaution is required when servicing SCR systems to handle DEF materials safely?

• A. Wear PPE to avoid electrical shock.
• B. Wear PPE for protection from high temperatures.
• C. Prevent skin and eye contact with the DEF (Urea).
• D. Remove loose clothing to prevent contact with the DEF (Urea).

Answer: (C)

Prevent skin and eye contact with the DEF urea solution. DEF is a urea-in-water fluid used in SCR systems, and while it’s not highly toxic, it can irritate the skin and eyes on contact. The safest, most direct precaution during servicing is to wear protective items like chemical-resistant gloves and safety goggles (or a face shield) to prevent exposure. If a spill or splash occurs, rinse skin with plenty of water and flush eyes with clean water for several minutes. Other PPE considerations, such as protection from electrical shocks or high temperatures, relate to different hazards around the system and do not address the primary DEF exposure risk; removing loose clothing isn’t a DEF-specific precaution.