May 6, 2021

NIOSH Evaluates Lead Exposures During Water Line Replacement Activities

A new health hazard evaluation report (PDF) published by NIOSH assesses lead exposures among crews replacing lead water lines servicing residential homes. The agency conducted the evaluation in response to a request by an employer who was concerned about lead exposures among workers after two employees were found to have elevated levels of lead in their blood. In July and September 2019, NIOSH personnel visited worksites to observe work processes and conduct exposure assessments for nine lead service line replacement workers. Eight of these individuals were considered “active workers” as they were directly involved with the lead service line replacement work. During NIOSH’s evaluation, agency staff held confidential medical interviews with all nine workers and two additional supervisors; collected personal air samples from the active workers; collected colorimetric wipe samples from the active workers’ hands before and after each water line replacement job; and took surface samples from the insides of active workers’ gloves, within work trucks, and at the main pump station. NIOSH’s team also attempted to determine whether lead particulate was expelled from the lead pipe during the replacement process.

Prior to NIOSH’s evaluation, two of the nine workers were found by their personal physicians to have blood lead levels (BLLs) of 5 micrograms per deciliter (μg/dL) and 6 μg/dL. During the evaluation, all nine workers underwent blood testing through their employer’s health program, and one of the workers, who had been identified as having an elevated BLL by their personal physician, was found to have a BLL of 5.7 μg/dL. (NIOSH’s Adult Blood Lead Epidemiology and Surveillance program considers an elevated BLL for adults to be 5 μg/dL or over.) The NIOSH team also found lead present on employees’ hands, inside work gloves, and on surfaces in work trucks and the locker rooms of the pump station. Although some workers wore respirators incorrectly, no air samples were found to be above 50 μg/m3, OSHA’s permissible exposure limit, NIOSH’s recommended exposure limit, and ACGIH’s threshold limit value for lead in air.

To address the workers’ lead exposures, NIOSH’s report recommends that the employer improve surveillance, training, and work practices. As the lead service line replacement process sometimes requires the use of compressed air to blow a string or rope through the pipe, which is then used to pull the pipe from the ground, these recommendations include ensuring that no workers are in the pipe trench while this procedure takes place to prevent them from inhaling lead particulate. Recommendations to improve personal protection equipment (PPE) use include allowing workers to change gloves more frequently and to wear nitrile gloves beneath their work gloves. The health hazard evaluation report also recommends that lead removal wipes and soap be stocked in trucks and locker rooms so that workers may thoroughly clean themselves and their tools after work is completed. Surfaces in trucks and at the pump station should also be regularly cleaned with lead removal wipes or soap. Finally, NIOSH urges the employer adopt frequent colorimetric wipe testing for hands, surfaces, and tools to identify sources of exposure and measure the effectiveness of cleaning procedures and PPE use.

For more information about NIOSH’s health hazard evaluation, refer to the report (PDF).