Machine vs Man: Can robotic mops clean to lead safety standards?

OBJECTIVES: Following home improvement activities on surfaces containing lead-based paint thorough cleaning is critical to ensuring the safety of occupants. A US Department of Housing and Urban Development (HUD) three-step process – cleaning all surfaces with a HEPA vacuum, wet washing with a surfactant, and a second vacuuming with a HEPA vacuum - is recommended to ensure surfaces are cleaned to an acceptably low lead level. Clearance failures require additional cleanings until minimum lead level standards are met. This study evaluated the use of a robotic mop for floor cleaning in houses with lead-based paint exposure during remodeling projects. STUDY DESIGN: The study evaluated the use of the robotic mop in conjunction with HUD's three-step cleaning process and compared its performance to those of professional cleaning crews following the same three-step process. An evaluation of 1,301 floors using a robotic mop was conducted with dust samples collected on floors prior to and following floor cleaning. Sampling site and lead dust wipe testing followed HUD protocols. Robotic mop operation followed printed manufacturer instructions. PRINCIPAL FINDINGS: 1,301 floors in 257 housing units were cleaned using the robotic mop; 63 floors failed the clearance test--a failure rate of 5%. Seventeen floors were re-cleaned with the robotic mop; 14 passed the clearance test on the second attempt. The three floors that failed were wood floors in poor condition. The remaining 46 floors and the three floors failing the second robotic attempt were cleaned by human crews. An audit of 995 human cleaning crew lead dust floor wipes from 2007-2009 found a 10% failure rate. CONCLUSIONS: Using a robotic mop results in floor clearance failure rates significantly lower than that obtained by human crews, allowing more time for contractors to focus on other surfaces requiring cleaning.