Control technology and exposure assessment for occupational exposure to beryllium: beryllium facility #3 - aluminum/beryllium foundry, and copper/beryllium foundry and machine shop, report no. EPHB 326-16a.
On September 26-27, 2007, the National Institute for Occupational Safety and Health (NIOSH) conducted an in-depth industrial hygiene survey at a facility with two foundries: an ingot foundry which manufactures aluminum/beryllium and copper/beryllium ingots; and a green sand foundry with a cutting and grinding operation which manufactures a variety of copper/beryllium products including non-sparking hand tools. The company employed a total of 20 employees in the two foundry operations and the cutting and grinding shop. The ingot foundry produces both aluminum/beryllium alloy and copper/beryllium alloy ingots containing 1.0 % to 5% beryllium. The green sand foundry and associated cutting and grinding operations produce a variety of copper/beryllium products containing a maximum of 4% beryllium, 0.25% up to 2.5% cobalt, 0% up to 1.8% nickel, with the balance being copper. The facility employed several control technology and administrative controls to reduce the potential for worker exposures to beryllium. The ingot foundry, green sand foundry and the cutting and grinding shop are beryllium designated areas with access limited to employees who have been trained and cleared to work in those areas. Employees entering beryllium designated areas are required to wear respiratory protection, protective clothing, safety glasses and safety shoes. Additionally, employees working in the cutting and grinding shop are required to use ear plugs or ear muffs for hearing protection. Employees must enter and exit the plant through a series of (clean) side locker room, shower room and beryllium side (dirty) changing rooms. At the end of their shift, employees exiting the beryllium designated areas must enter the dirty side locker room, remove company provided work clothing, shower, and change to street clothing in the clean side locker room before leaving the worksite. The employee lunch room in the building is physically divided to separate the beryllium side of the building from the clean side (see plant diagram), and the two lunch rooms are on separate HVAC systems. The beryllium ingot foundry, the green sand foundry and the cutting and grinding operations were equipped with local exhaust ventilation (canopy hoods, side draft, slot, etc.) to reduce process emissions. All workers wore half-face MSA Comfo air purifying respirators equipped with P-100 cartridges or 3M 8293 P-100 disposable filtering face masks in beryllium designated areas including the two foundry areas, green sand molding operation, melt shop, shake out, cut off, and grinding areas. Additionally, when pouring molten metal and certain other operations, workers wore protective jackets, gloves, leg protection and face shields. Air sampling results indicate that three samples exceeded the NIOSH REL for beryllium (0.5 µg/m3) while none exceeded the OSHA PEL (2 µg/m3). The three samples that exceeded the NIOSH beryllium REL were personal samples: one sample collected on the copper/beryllium foundry supervisor showed a concentration of 0.58 µg/m3; one collected on the aluminum/beryllium furnace operator showed a concentration of 0.55 µg/m3; and one collected on a grinding room employee showed a concentration of 1.07 µg/m3. The highest copper metal dust concentration detected was less than 5% of the NIOSH and OSHA criteria (1000 µg/m3); the highest copper metal fume concentration detected was less than 6% of the NIOSH and OSHA criteria (100 µg/m3); and the highest aluminum concentration detected was less than 5% of the NIOSH and OSHA criteria (5000 µg/m3). Surface wipe sample results indicated measurable quantities of beryllium ranging from 0.2 µg/100 cm2 up to 180 µg/100 cm2. The lowest beryllium surface concentrations detected (0.2 µg/100 cm2) were on a table top in the clean side lunch room and a concentration of 0.7 µg/100 cm2 was detected on the table top in the beryllium side of the lunch room. These levels are below the DOE Guideline (3 µg/100 cm2) for nonoperational periods. The two lunch rooms had separate entrances and separate HVAC systems. The highest beryllium surface concentration detected (180 µg/100 cm2) was on a wood workbench surface in the aluminum/beryllium ingot foundry. Another sample collected on a workbench in the copper/beryllium foundry area showed a surface concentration of 95 µg/100 cm2. Employees spend a lot of time at these benches where they frequently touch the surfaces as they fill-in work logs to document work orders. These levels are many times the DOE Guidelines which recommend that removable surface contamination levels be maintained at concentrations that do not exceed 3 µg/100 cm2 during non-operational periods. The results of size-selective sampling show beryllium was detected on six of the 11 personal samples collected; two of these six samples indicate measurable quantities of beryllium particles in stage B (size range 1.0 to 2.5 µm). This tends to suggest that some airborne beryllium is present in concentrations that may potentially reach lower portions of the respiratory tract. Recommendations to further reduce airborne beryllium concentrations and controlling worker exposures to beryllium-containing dust and fume at this facility are included in the body of this report.
Control-technology; Beryllium-compounds; Copper-compounds; Aluminum-compounds; Dust-particles; Dust-sampling; Foundries; Foundry-sands; Foundry-workers; Heavy-metals; Exposure-assessment; Machine-shop-workers; Work-areas; Work-clothing; Work-practices; Air-sampling; Exposure-levels; Exposure-limits; Metal-dusts; Personal-protective-equipment
National Institute for Occupational Safety and Health Division of Applied Research and Technology 4676 Columbia Parkway, Mail Stop R-5, Cincinnati, OH 45226