On September 29, 1993, a worker at the Lawrence Livermore National Laboratory became contaminated while working in a glovebox workstation. The worker was using emery paper to remove carbon deposits from a part in the glovebox and he was wearing a lab coat, protective shoe covers, and surgeon gloves. While working, he looked through the glovebox window to determine if there was visual evidence of wear on the fingertips of the gloves. In the event of such wear, he was to notify Health and Safety personnel to initiate a glove change before the integrity of a glove was lost.
During performance of the job, the worker observed a tear in the tip of the right index finger of the box glove. Without withdrawing his hands from the box gloves he told another worker to summon a health and safety technician to perform a glove change. While waiting for a Health and Safety technician to respond, the worker withdrew his left hand from the box glove and surveyed the surgeon glove he was wearing on a box mounted alpha survey instrument. He detected contamination and put his hand back into the box glove in an effort to prevent a spread of contamination. The Health and Safety technicians responding to the event evaluated the situation and placed the room on respiratory protection. They monitored the worker and discovered contamination on his left hand surgeon glove, sleeve, right shoe cover, and lab coat. After removal of the surgeon gloves, Health and Safety technicians initially detected contamination on the workers right hand of approximately 160,000 dpm per detector probe area of 126 square cm.
The worker was escorted to the facility personnel decontamination area and Health and Safety technicians posted the room for restricted access. They surveyed the work area and detected approximately 20,000 dpm on the floor below the glove ports, 30,000 dpm on the right glove port ring and 16,000 dpm on the floor on the opposite side of the glovebox. Lower levels of contamination were detected in several other areas. Health Physics personnel conducted a detailed personnel survey and detected approximately 200,000 dpm on the tip of the worker's index finger. They collected nose swipes from the two workers, and preliminary radioassay of the swipes did not detect contamination. Facility personnel continued to investigate corrective actions and lessons learned. (ORPS Report SAN--LLNL-LLNL-1993-0063)
Research of the ORPS database indicated numerous personnel contamination events at this facility. Examples of these events include the following:
On April 5, 1993, a worker became contaminated when he grasped the knurled top of a cylinder to unscrew it and breached a box glove. The incident investigators concluded that the worker should have used channel locks to open the cylinder. (ORPS Report SAN-LLNL-LLNL-1993-0027)
On March 27, 1993, a worker failed to properly frisk his arm after work in a glovebox, in violation of the directives of the Facility Safety Procedure Manual. Unbeknown to the worker at that time, one of the box gloves had a crack in the crease of the elbow and contamination was transferred to the arm of his lab coat. He subsequently contaminated his hand when he reused the lab coat the following day. (ORPS Report SAN-LLNL-LLNL-1993-0024)
On February 24, 1993, a worker removed his hands from a glovebox and wiped his nose with the left sleeve of his lab coat. He then monitored his hands with the alpha monitor and discovered contamination. Approximately 1,000 dpm contamination was detected on his face, and radioassay results detected 17 and 13 dpm on the swipe of the worker's nostrils. Incident investigators determined that the gloves creased and breached because of repeated torque on the gloves whenever a screwdriver was used to pry a plutonium sample out of a resin holder. The gloves were over two years old. (ORPS Report SAN-LLNL-LLNL-1993-0014)
On October 10, 1992, a chemist punctured his glove and thumb with a broken contaminated pipette while working in a glovebox. Incident investigators determined that inattention to the hazards of sharp items contributed to the event. In addition, they concluded that the safety program concentrated on potential inhalation risks rather than all risks encountered in glove box work. (ORPS Report SAN-LLNL-LLNL-1992-0090)
On October 29, 1991, two workers were contaminated when they deviated from procedures for the bag-out of plutonium oxide. Instead of properly placing the material in a rigid-walled container in accordance with procedures, the workers used bag-out bags. Incident investigators concluded that the oxide leaked through the bags during transfer of the material. They detected contamination on the floor of the work area of 10,000 to 20,000 dpm. (ORPS Report SAN-LLNL-LLNL-1991-1056)
These events highlight the need for emphasizing to workers the importance of staying alert on the job and following procedures established for glovebox work and personnel monitoring. In addition, facility management should consider routine replacement of box gloves for frequent operations that have a potential for increasing wear. These events also point out the importance of using extreme care when working with sharp objects in a radiation contaminated environment. A wound sustained under such circumstances can be difficult to decontaminate. Facilities should consider alternate methods of handling contaminated sharp objects and substitute, where possible, unbreakable laboratory equipment for glovebox use.