NSLS ESH Highlight #9

Guidelines for Working with Lead on the NSLS Experimental Floor

Date: April 16, 1997
Editor: A. Ackerman, N. Gmür, W. Thomlinson

Introduction

• The health effects of lead exposure are well documented and have been studied for many years. It is a potent systemic poison with several target organs including, the gastrointestinal tract, the central nervous system, the kidneys, and the blood. Typical routes of exposure are through inhalation and accidental ingestion. Any exposure to lead through inhalation is a concern as lead is efficiently transferred to the blood by the lungs. Systemic absorption through the gut is less efficient with perhaps as little as 30% of what is eaten migrating to the blood. Inorganic lead is not absorbed through intact skin.
• Lead exposure, in the occupational setting, is governed by an OSHA standard; 29 CFR 1910.1025. That standard contains limits for both airborne lead concentrations and blood lead levels for workers handling lead. They are restrictive. Airborne concentrations at or above 30 micrograms/cubic meter of air trigger training and monitoring requirements. Blood lead levels at or above 40 micrograms/100 grams of blood are considered excessive and trigger notification requirements and require removal from exposure. Note that those units are micrograms so it does not take much lead to be a concern. Even if you account for the poor absorption through the gut, a person need only ingest a few milligrams of lead to exceed limits.
• Lead has a low vapor pressure so airborne concentrations are not generated unless the material is mechanically disturbed as in sanding or filing. Cutting the material with shears creates little dust. Lead that is significantly oxidized is different. The oxide layer is finely divided and could be dispersed, creating an inhalation hazard.

NSLS Lead Concerns

Lead exposures resulting from placement of shielding on the beam lines are easily minimized. As we do not expect to need any machining of the material, our only significant concern is accidental ingestion. We need to take measures to avoid accumulation of lead on hands and clothing and to minimize tracking of any loose material throughout the facility. Attention to personal hygiene and housekeeping practices will be adequate to minimize exposures. Specific guidelines follow.

Suggested Work Practices

Gloves should be worn when handling lead. Common cloth work gloves are adequate. When gloves are inconvenient and interfere with efficient work progress, work with bare hands is acceptable but requires additional attention to personal hygiene. If you must work with bare hands, you must wash often and be attentive to keeping your hands away from your face and clothing. If you handle lead with bare hands, you will have lead on your hands. Cloth aprons or lab coats should be worn when handling lead. This practice will help reduce contamination of clothing. Aprons or lab coats are most needed when working with larger pieces of material or when working with lead for extended times (several hours). A table or desktop should be designated as the lead work area. That surface should be completely cleared and covered with disposable paper or plastic material. All the lead should be kept on this table. This surface should be used for cutting and forming the sheet. You should leave your gloves and apron on the table when removing them. We want to limit tracking of lead on the floor and keeping most of the work on a table top will help. Periodic changing of the surface covering may be needed.

NSLS Supply and Storage

• Lead Sheet (3’ x 5’ x 1/16") will be available on pallets near the Stock Room. Lead scrap is considered hazardous waste. We will have a cart and wooden boxes near the NSLS Stock Room. Larger pieces that are still useful should be placed on the cart for anyone who wants them. Smaller scrap, to be discarded, should be placed in the wooden boxes. Contaminated covering material should be placed in plastic bags and may be kept at the beam line until the work is complete. Contaminated gloves and aprons should be added to the same bag. All these materials must be discarded as Hazardous Waste. A supply of plastic bags will be available next to the lead cart near the NSLS Stock Room. For proper disposal, contact John Aloi at ext. 7018.  Once work is complete, arrangements should be made with the NSLS Floor Manager to have the custodians damp mop the floor area around your beam line.
• Wash your hands as often as practical.

Helpful BNL Warehouse Stock Numbers

• Gloves, Cotton - #K62940 - available for purchase in the NSLS Stock Room
• Gloves, Cotton Canvas - #K63020
• Apron, Laboratory, Vinyl plastic - #K60140 - available for purchase in the NSLS Stock Room
• Apron, Laboratory, Disposable - #K60142
• Coat, Laboratory, Tan Cotton - #K60814Ž #K60840 depending upon size
• Plastic Film - #G06750, #G06755, #G06757, #G06380
• Bags, Plastic - available in the Pb setup area
• Paper, Kraft, Untreated - #I81200(36" wide) - available in the Pb setup area
• Snips, Metal Cutting - #H23910;(straight), #H23912(right), #H23914(left) - 10" long
• #H23870 - 17" long
• #H23890 - 12.5" long
• Clamp, Hose - #I59005Ž #I59026 - available for purchase in the NSLS Stock Room; larger diameter hose clamps must be purchased in local hardware stores
• Do-It-Yourself Clamp Kits - available soon in the NSLS Stock Room
• Tie Wraps, Plastic - #A59826 (29") - available for purchase in the NSLS Stock Room
• Banding, Plastic and Clips - available in the Pb setup area

Lead Machining in NSLS Tech Shops

1. If at all possible, take lead to be machined to the BNL Hot Shop.
2. Do Not Machine Oxidized Lead.
3. Do wear gloves, boots and other overwear to prevent contamination of personal clothing. Keep lead chips contained to as small an area as possible. Cover flooring to catch all chips formed by your work. Treat lead chips as Hazardous Waste. Contact John Aloi @ x7018 to properly dispose of scrap lead.