Lead and Arsenic Exposure Control for Waste to Energy Furnace Cleaning

In 1997, the Hampton/NASA Steam Plant implemented a successfully re-engineered wet cleaning process for controlling exposure to lead and cadmium during the cleaning and maintenance of electrostatic precipitators. The following year we were ready to apply the lessons learned to the initial furnace cleaning tasks. As part of the initial process review, industrial hygiene (IH) tests were done during furnace cleaning using the in practice methods. Testing was done for respirable lead and cadmium. Lead exposure was found to be over the action level, but cadmium exposures were just around non-detect levels. May of 1999 the facility became aware, through an IWSA-MWMA-ASME Safety and Health Seminar, that other WTE facilities were testing for arsenic as well. Another set of tests were performed that same month which included tests for respirable arsenic. The results showed that arsenic was present and found to be over the action level, and one test point was especially high during the sifting hopper cleaning part of the procedure. These results were surprising since IH testing for these tasks during 1987 indicated much lower exposures. It was decided the procedures had to be changed. Two process improvement outcomes were targeted: 1) To prevent accidents, injuries and close calls during the furnace cleaning task, a safer procedure for the task of furnace cleaning would be developed. 2) The new procedure must control cadmium, lead and arsenic exposures during furnace and sifting hopper cleaning tasks, to below OSHA Action Levels. The new procedure standardized cleaning methods and included use of water right from the initial entry into the furnace. Operators had respirators upgraded to Positive Pressure Air Purifying Respirators (PAPR) and wore special disposable coveralls. Subsequent Industrial Hygiene testing showed that exposure levels could be reduced to less than the OSHA Action Level and Permissible Exposure Limits for lead and arsenic. The newly developed “wet cleaning” procedure provided a safer standardized procedure that the Operators helped to develop, and Operators feel safer doing the task. The new procedure has also reduced task worker exposures to Lead and Arsenic to below OSHA Action Levels.