If upper and lower walls have different painting histories, what must be done?

• A. Test only the upper wall
• B. Test only the lower wall
• C. Four tests are required of each
• D. No extra tests are needed

Answer: (C)

When two sections of a wall have different painting histories, the coatings and potential lead content can vary by layer. A single test might miss a lead-containing layer beneath or between coats, especially if older lead-based paint sits under newer finishes. Testing four times on each wall area ensures you sample across the variations—capturing different layers and locations—so you don’t overlook lead wherever it may be present. This thorough approach provides a more reliable assessment and supports proper decisions about lead hazard controls. Testing only one area or skipping extra samples could miss lead; likewise, applying more tests than necessary to the whole surface isn't as efficient. Therefore, four tests are required for each area.