ERG investigators monitored all three workers involved with the melting and casting operations. Worker job descriptions include furnace operator, furnace helper, and forklift operator. The furnace operator oversees the melt and subsequent pour from the furnace. During the melt, the furnace operator works from a 1-meter high platform surrounding the furnace. Work tasks include rubbing, skimming, and sparging. Dross is skimmed using a ladle and thrown into a bucket underneath a hood on the work platform. (Investigators noted that the method used to transfer dross causes contamination to be spread outside the ventilated buckets.) Much of the time involves waiting for the loaded furnace to melt the ingots placed in it at the start of the shift. During that time, all the workers generally are in the office, as noted previously. From time to time, the furnace operator leaves the office and returns to the work platform to check the temperature of the melt and may collect samples for analysis before the pour begins. During the pour, the furnace operator controls the pour into the mold or tundish (ERG Beryllium Site 7, 2003). The furnace helper assists the furnace operator and is usually nearby (ERG Beryllium Site 7, 2003).  However, the furnace helper does not participate in and is not close by during the pour (ERG Beryllium Site 7, 2003). During the ERG visit, the pour lasted 15 to 20 minutes (ERG Beryllium Site 7, 2003).
The forklift operator moves the crates containing the furnace charge material (ingots) using an open-cab forklift. The ingots are primarily unloaded by hand into the furnace. The forklift operator moves the tundish into position, may remove billets from the mold if a larger single piece is being cast, and cuts the billets on the band saw, if necessary, depending on customer specifications (ERG Beryllium Site 7, 2003).
ERG investigators collected a total of four personal breathing zone (PBZ) total beryllium samples for the three workers described above, which were analyzed by OSHA Method ID-125G (Metal and Metalloid Particulates in Workplace Atmospheres) using inductively coupled argon plasma-atomic emission spectroscopy (ICAP-AES). The laboratory analytical reporting limit was 0.02 micrograms per filter. As with ERG Beryllium Site 2 (2003), three of the samples are less-than-full-shift duration (two for furnace helper and one for forklift operator). Nevertheless, OSHA has determined that in the absence of other recent exposure data for comparable facilities, these sample results offer the best available information on this portion of the industry, although, for reasons explained below, they might overestimate exposures somewhat.
Controls in Place
The primary exposure control in the facility is a canopy hood located over the furnace to capture fumes from the melt. LEV includes canopy hoods over casting stations, ingot conveyors, and dross buckets (Corbett, 2005). The main hood covers the charge platform for the furnace such that workers stand in the path of the exhaust ventilation over the furnace. The transfer of rubbing and skimming tools from the furnace is not ventilated (i.e., rubbing and skimming tools are fuming when they are removed from the furnace), and a significant number of 90-degree transitions in the exhaust ducts were noted (Corbett, 2005).
Workers wear company-provided work clothes, and a washer and dryer are available on the premises for cleaning these clothes. During the pour, aluminized/heat-reflective suits and gloves are required for thermal protection. All three workers wear respiratory protection during the pour; at other times some workers don respirators whenever fume is visible. The furnace room and the offices are not separated by different air supply systems, and the doors between them are usually open. Evidence of cross-contamination is visible, as the graphite used to coat the molds for quick release of the ingots can be seen covering numerous surfaces in the offices (ERG Beryllium Site 7, 2003).
Additional Sources of Information
The following sources also contributed information to this analysis. Exposure data from these sources are not included in the exposure profile but were considered in OSHA's analysis.
ERG Walk-through Visit at an Electronic Recycling and Sampling Facility
ERG staff visited a facility that receives and samples regular-grade electronic scrap (including circuit boards, integrated circuits, trim from circuit board manufacturing, connectors, and other electronic parts) prior to shipment to the company's smelter (at a different location) (ERG Site Visit, 2005). The firm also receives some metallic inputs, such as scrap from a copper punching operation. The non-electronic scrap represents only about 15 percent of its inputs. Circuit boards comprise about 80 percent of the electronic scrap. The sample results determine the payment customers will receive for the precious metal content recovered from the shipments. The samples also identify hazardous constituents in the samples and are used to determine whether the facility is willing to process the materials. Beryllium is typically not a major constituent of this scrap. In fact, the facility will not accept scrap with beryllium levels exceeding 200 parts per million.
No personal or area sampling was conducted during the ERG visit, but facility representatives informed ERG interviewers that employees are monitored for beryllium exposure on a monthly basis. The company uses an 8-hour time-weighted average (TWA) action level of 0.1 μg/m[3] for PBZ samples but typically maintains exposure levels of 0.03 μg/m[3].
NIOSH Visits to Federal Penitentiary Electronic Recycling Operations
Between August 2008 and January 2009, NIOSH investigators conducted studies of the recycling of electronic components at Federal Prison Industry operations at three federal penitentiaries to assess workers' exposures to metals, including beryllium, and to other occupational hazards associated with these operations (e.g., lead, cadmium) (NIOSH EPHB 326-12a; NIOSH EPHB 326-15a; NIOSH EPHB 326-17a). The processes NIOSH observed included receiving and sorting, disassembly, glass-breaking operations, packaging and shipping, and cleaning and maintenance.
Material received for recycling primarily consisted of computers (both desktops and laptops) and related devices such as printers. Electronic memory devices were removed and degaussed or destroyed, and CPUs, servers, and similar devices were sent for disassembly. Monitors and other devices with CRTs were sent for disassembly and removal of the CRT. Inks and toners were removed from printers, copiers, and other similar equipment prior to being sent to the disassembly area.
During disassembly, the devices were taken apart, and valuable materials such as copper wiring and aluminum framing were removed and sorted by grade. Components such as circuit boards or chips that might have value or otherwise contain precious metals such as gold or silver were also removed and sorted. In the glass-breaking operation, workers used hammers to remove electron guns from CRTs and then break the funnel glass. During the subsequent packing and shipping operations, materials (i.e., those separated during disassembly and glass breaking activities) were moved to the loading dock for shipment. Some items, such as plastic cabinets and metal frames were compacted for easier shipment, while other materials were boxed prior to shipment.
Combined, NIOSH researchers took 112 PBZ samples during the recycling operation visits. Almost all of these samples were less than full shift in duration (i.e., < 360 minutes), and only two showed detectable levels of beryllium. Both of these samples were less than 4 hours in duration and included results of 0.07 ug/m[3] (187 minutes) for a metal bailer and 0.08 ug/m[3] (164 minutes) for a disassembly worker. The remaining sample results all indicated that exposure concentrations were less than the limits of detection (LODs), which ranged from 0.005 ug/m[3] to 0.1 ug/m[3] (most were 0.03 ug/m[3] or less).
NIOSH reported that engineering controls were used at two of the three locations at which the glass breaking was performed. At one of those locations the controls consisted of an enclosed booth with an LEV system. At the other location, glass breaking was performed beneath a large ventilated walk-in hood. Glass breaking was the only process where LEV was utilized.
The evidence from these studies indicates that workers engaged in recycling operations such as those sampled by NIOSH (demanufacturing and CRT recycling) are not at risk of significant beryllium exposures. However, the operations at these facilities did not include crushing, shredding, sampling, or melting activities (such as observed at ERG Beryllium Site 2), which might be expected to produce significant exposures (see Table IV-37). Because workers at these facilities are not engaged in activities that create risk of exposure to beryllium (even without control measures), the sample results from these evaluations are not included in the exposure profile.
Kent et al. -- Air Monitoring of Cellular Telephone Recycling at an Electronic Scrap Processing Facility
Investigators conducted air monitoring for metals, including beryllium, while workers recycled cellular telephones at an electronic scrap processing facility. The sampled operations included shredding, roasting, milling (including screening to separate -20 to +20 mesh fractions of crushed material), and assaying (sampling and analyzing) recycled cellular phones. A sample of five phones contained 52 parts per million (ppm, by weight) beryllium. The summarized results of multiple 8-hour PBZ samples indicated that no worker exposure exceeded 0.2 ug/m[3] (the company's internal occupational exposure limit) during any of the operations. Average beryllium concentrations over a 5-week sampling period were 0.01 ug/m[3] for shredding (16 samples), 0.01 ug/m[3] during roasting (18 samples), 0.02 ug/m[3] during milling (9 samples), and 0.05 ug/m[3] for alloying activities (16 samples). At this plant, several measures had been implemented to manage airborne metal dusts, including partial enclosures and exhaust ventilation on the shredder, material sampling equipment, and conveyor belt drop points, as well as at product transfer points associated with the mill, roasting oven, and furnace, and in the ingot descaling (finishing) area (Kent et al., 2007). Individual exposure results were not provided; therefore, the results of this study are not included in the exposure profile.
Vincent et al. -- Air Monitoring in Industries Recycling Metal and Non-Metal Waste and Scrap
Investigators in France evaluated beryllium exposures in several industries, including those recycling metal and non-metal waste and scrap. Twenty-three personal and area air samples obtained during dismantling of electrical waste ranged from 0.004 ug/m[3] to 0.038 ug/m[3], with a median of 0.03 ug/m[3] (Vincent et al., 2009). Air samples were 4 to 6 hours in duration and reportedly represented the activities workers performed for their entire shift. Most samples were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES); however, a few were analyzed by atomic absorption spectrometry (depending on the laboratory). Overall, the median reported limit of quantification (LOQ) was 0.015 μg/m[3] (range 0.001 to 0.2 μg/m[3]) for all samples obtained in this study of numerous French industries. The sample LOQ concentration exceeded 0.05 μg/m[3] 14 percent of the time (Vincent et al., 2009). The recommended occupational exposure limit for beryllium in France is the same as the current U.S. permissible exposure level (PEL) of 2 ug/m[3]. The study did not provide information about worker activities or exposure controls.  Together, the four reports described above suggest that beryllium exposure levels are generally low during electronic waste recycling activities. (ERG Site Visit, 2005; NIOSH EPHB 326-12a; Kent et al., 2007; and Vincent et al., 2009).
NIOSH -- Precious Metals Refining (Handy and Harman)
NIOSH conducted an HHE at Handy and Harman, Inc. in Fairfield, Connecticut, in July and November 1983 (NIOSH HETA 83-162-1746). Operations at the Handy and Harman facility included refining precious metals from industrial scrap and fabricating silver and gold alloys in various mill forms. NIOSH described operations at Handy and Harman as primarily involving recoverable scrap, including precious metal-bearing scrap from the computer, electronics, chemical, photographic, and decorative industries. The report offers considerable detail on the processes used in this establishment. At the time of the 1983 evaluation, the processes and ventilation systems had remained essentially the same for decades. NIOSH noted numerous areas in which control measures could be improved (i.e., repairing leaking ventilation systems, adding baffles and enclosures, reducing the extent to which materials were intentionally or inadvertently dumped on the floor and later swept or shoveled, and reducing reliance on compressed air for cleaning).
NIOSH investigators collected a total of 160 full-shift (7 to 8 hours) PBZ samples while workers at Handy and Harman were engaged in the following activities: mechanical processing (e.g., crushing, screening, and ball milling), sampling, housekeeping, and furnace and casting operations. NIOSH indicated that sampling was well-distributed across job categories and work shifts. The samples were analyzed by NIOSH for beryllium and various other metals using ICP-AES. The volume-adjusted lower LOQ for beryllium was reported to be 0.5 μg/filter (NIOSH HETA 83-162-1746). By comparison, NIOSH's current LOD for beryllium is 0.005 μg/filter using the NIOSH Method 7300. During NIOSH's 1983 evaluation, a large portion of the sample concentrations (55 percent) were below the LOD, which for that NIOSH evaluation ranged from 0.21 μg/m[3] to 0.6 μg/m[3] (above OSHA's current range of interest for this analysis) (NIOSH HETA 83-162-1746).
OSHA compared the findings from the 1983 NIOSH Handy and Harman HHE to those from more recent studies of precious metal refining operations and determined that many of the same general steps are still in use today; however, concerns about environmental and workplace health and safety have led to increased attention to exposure management (Kent, 2007). As a result, in similar facilities, improved engineering controls and work practices are in place and, thus, current worker beryllium exposure levels are considerably lower than were measured by NIOSH 30 years ago (Kent et al., 2007; Vincent, 2009). Based on the high LOD; the large number of nondetectable samples; and current evidence that in precious metal recovery facilities, exposure levels today are considerably lower than reported in 1983 by NIOSH, OSHA has eliminated this otherwise robust dataset from the exposure profile. The Handy and Harman report remains a source of general information about processes, equipment, and historic exposure levels in the precious metal refining industry and furnace operations in general.
IMIS
ERG reviewed unpublished exposure data from IMIS for beryllium (OSHA, 2009). These data, however, can be difficult to interpret because the database is not designed to capture information pertaining to worker activities, workplace conditions, engineering controls, personal protective equipment, and nondetectable sample concentrations and durations. Furthermore, job categories may not be systematically sampled for possible beryllium exposures. For these reasons, sample results from IMIS are not included in the exposure profile.
The IMIS database for the secondary smelting, refining, and alloying industry contains a total of 655 PBZ samples collected on workers from June 1978 to September 2008 in the matching SIC classifications: 3341 (Secondary Smelting and Refining of Nonferrous Metals); 3399 (Primary Metal Products, Not Elsewhere Classified); and 4953 (Refuse Systems). Detectable levels of beryllium were found for 334 (51 percent) of these samples. Table IV-36 summarizes the IMIS findings. Only positive IMIS results have been included in the analysis because the volume-adjusted reporting limit concentrations for nondetectable samples are not available to ERG. For the SIC groups combined, the median value is 0.6 μg/m[3], the mean is 1.85 μg/m[3], and the range is 0.006 g/m[3] to 19.0 μg/m[3]. Given that 50 percent of the IMIS entries are nondetectable, the true median for these SIC groups might be less than 0.6 μg/m[3]. It should be noted that all the positive samples reported for SIC 3399 were apparently taken at Materion Corporation's Elmore, Ohio, plant. The results from 1997 and 1999 inspections of that facility were classified under this SIC code. Since Materion Corporation operates a vertically integrated operation, including the production of alloys from beryllium scrap, these sampling results are relevant to the application group under consideration here.

Table IV-36 -- IMIS PBZ Total Beryllium Air Sampling Results for Establishments Engaged in Secondary Smelting/Refining, Alloying, and Recycling: SIC Groups 3341, 3399 and 4953[a]
                                   SIC Code
                        Total Number of Establishments
                                SIC Description
        Total PBZ Samples/
Number PBZ Samples with Positive Results[b]
   Job Descriptions
(Positive Results Only)
(as listed in the IMIS database)
                              Range[c]
(μg/m[3])
                              Mean[c]
(μg/m[3])
                             Median[c]
(μg/m[3])
                                     3341
                                      79
Secondary Smelting and Refining of Nonferrous Metals
552/299
(54.2% positive)
Arc room arc furnace; assistant operator slab mill; baghouse operator; bail mill 2,3,4; ball mill operator; briquetter operator; caster; charge shed operator #1; crusher; electrician; foundry laborer; furnace operator; furnace helper; incinerator operator; kiln operator; laborer; lead man mill blend; lift truck driver; mold maker; pan man; ring mill operator; saw man; sorter; tool assembly[d]
                                0.006 to 19.0a
                                      1.8
                                      0.5
                                     3399
                                      14
Primary Metal Products, Not Elsewhere Classified
52/28
(53.8% positive)
Furnace operator; helper coiler; laundry operator; lead operator; mill operator; mix make-up operator; trainee
                                  0.1 to 9.3
                                      2.3
                                      1.1
                                     4953
                                      22
Refuse Systems
61/7
(11.5% positive)
Bull dozer operator; mechanic/welder; welder
                                 0.01 to 12.0
                                      1.8
                                     0.01
                                     Total
                                      115

665/334
(50% positive)

                                 0.006 to 19.0
                                     1.85
                                      0.6
[a]	This table does not include an outlier maximum exposure value of 3,671 μg/m[3] reported for a worker with the job description of caster. This PBZ sample was collected in 1990 at a beryllium alloyer covered by this application group. However, a second sample collected on a caster at this facility on the same date had a result of 19.0 g/m[3]. No information is available to account for such a substantial difference in exposure for this job category.
[b]	Includes all PBZ samples by SIC code.
[c]	The range, mean, and median results are based on positive sample results only. All positive results are included regardless of the total sample time.
[d]	Summarized job descriptions. The complete listing of job descriptions for SIC 3341 with positive results includes 80 different descriptions as entered into the IMIS database.

Source: OSHA, 2009 (OSHA Integrated Management Information System). Information regarding worker activities, the engineering controls in place, personal protective equipment worn during sampling, and nondetectable sample concentrations and durations is not available through the IMIS database.

Exposure Profile by Job Category
To determine the exposure profile of refining, smelting, and alloying workers, OSHA used data from the ERG site visits to a precious/base metals recovery facility and a facility that melts and casts beryllium-containing alloys (ERG Beryllium Site 2, 2003; ERG Beryllium Site 7, 2003). Together, these sources cover all the work activities in secondary refining, smelting, and alloying facilities discussed in this section. The sample results contained in these reports represent the best exposure data available to OSHA to characterize beryllium exposure in the refining, smelting, and alloying application group. Although recent exposure data for this application group are extremely limited, OSHA finds that these limited data are well supported by summary information in other recent reports that could not be included in the exposure profile because of insufficient detail.
Tables IV-37 and IV-38 represent the exposure profile for refining and alloying establishments. These tables summarize all of the available full-shift PBZ total beryllium exposure data. Nondetectable sample results are included in the exposure profile (all less than 0.1 ug/m[3]). Results reported as less than the analytical LOD or LOQ are incorporated into the exposure profile as volume-adjusted LOD or LOQ (reporting limit) concentrations. This is a conservative approach that may overestimate the exposure results.
Table IV-37 -- Personal Exposure Profile in the Refining, Smelting and Alloying Application Group
(NAICS 331314, 331423, 331492)[a,b]
                                 Job Category
                              No. of PBZ Samples
                               Range (μg/m[3])
                                Mean (μg/m[3])
                               Median (μg/m[3])
Mechanical processing operator
                                       3
                                  0.03 to 0.2
                                     0.14
                                     0.20
Furnace operations worker
                                       6
                                 0.03 to 14.08
                                     3.85
                                     2.15
   Beryllium recovery and alloying
                                       4
                                 1.92 to 14.08
                                     5.64
                                     3.28
   Other recycling and precious metal recovery
                                       2
                                  0.03 to 0.5
                                     0.26
                                     0.26
TOTAL
                                       9
                                 0.03 to 14.08
                                     2.61
                                      0.5
[a]	Sample results are used as presented by the source investigators. Sample duration is greater than or equal to 6 hours for all results, except the furnace operations worker job category, which includes three samples of 265 to 314 minutes duration.
[b]	Nondetectable sample results are included in the exposure profile. Results reported as less than the analytical limit of detection (LOD) or quantitation (LOQ) are incorporated into the exposure profile as volume-adjusted LOD or LOQ concentrations. This is a conservative approach that may overestimate the exposure results. All such results are less than 0.1 μg/m[3].

Sources: ERG Beryllium Site 2, 2003; ERG Beryllium Site 7, 2003

Table IV-38 -- Distribution of Full-Shift PBZ Exposure Results for Total Beryllium in the Refining, Smelting and Alloying Application Group (NAICS 331314, 331423, 331492)[a,b]
                                 Job Category
                     Number of Results in Range (ug/m[3])
                                     Total

                                   < 0.1
                              <= 0.1 to
<= 0.2
                              > 0.2 to
<= 0.5
                              > 0.5 to
<= 1.0
                              > 1.0 to
<= 2.0
                                   > 2.0

Mechanical processing operator
                                   1
(33.3%)
                                   2
(66.7%)
                                   0
(0.0%)
                                   0
(0.0%)
                                   0
(0.0%)
                                   0
(0.0%)
                                  3
(100.0%)
Furnace operations workers
(total)
                                   1
(16.7%)
                                   0
(0.0%)
                                   1
(16.7%)
                                   0
(0.0%)
                                   1
(16.7%)
                                   3
(50.0%)
                                  6
(100.0%)

Furnace operations workers in beryllium recovery and alloying
                                   0
(0.0%)
                                   0
(0.0%)
                                   0
(0.0%)
                                   0
(0.0%)
                                   1
(25.0%)
                                   3
(75.0%)
                                  4
(100.0%)

Furnace operations workers in other recycling and precious metal recovery
                                   1
(50.0%)
                                   0
(0.0%)
                                   1
(50.0%)
                                   0
(0.0%)
                                   0
(0.0%)

(0.0%)
                                  2
(100.0%)
TOTAL
                                       2
                                    (22.2%)
                                   2
(22.2%)
                                   1
(11.1%)
                                   0
(0.0%)
                                   1
(11.1%)
                                   3
(33.3%)
                                  9
(100.0%)
[a]	Sample results are used as presented by the source investigators. NIOSH (HETA 83-162-1746) results are 8-hour TWAs. Sample duration is greater than or equal to 6 hours for all results except the furnace operations workers job category, which includes three samples of 265 to 314 minutes duration.
[b]	A nondetectable sample result (less than 0.1 ug/m[3]) is included in the exposure profile. Results reported as less than the analytical LOD or LOQ are incorporated into the exposure profile as volume-adjusted LOD or LOQ concentrations. This is a conservative approach that may overestimate the exposure results.

Sources: ERG Beryllium Site 2, 2003; ERG Beryllium Site 7, 2003

Mechanical Processing Operator
The exposure profile for mechanical processing operators is presented in Tables IV-37 and IV-38. This profile represents the best available exposure data. As shown in Table IV-37, the exposure profile is based on three sample results and is described by a median of 0.2 μg/m[3], a mean of 0.14 μg/m[3], and a range from 0.03 μg/m3 to 0.2 μg/m[3]. Table IV-38 indicates all (100 percent) of sample results for this job category are 0.2 ug/m[3] or less.
Working conditions are well documented for the three mechanical processing operator samples in the exposure profile obtained at ERG Beryllium Site 2. The screening, blending, and ball milling processes are operated under negative pressure, with isolated product transfer and milling ducted to the central vacuum and baghouse filtration systems. Despite these controls, investigators observed visible emissions escaping the exhaust hoods and noted that major changes need to be made to bring the system into compliance with recognized design standards for ventilation systems (ERG Beryllium Site 2, 2003).
Although this exposure profile is based on samples collected at just one facility, it is supported by equally low results obtained at similar facilities where mixed or electronic waste are refined (Kent et al., 2007; Vincent et al., 2009; ERG Site Visit, 2005). Kent et al. obtained multiple 8-hour PBZ samples over several weeks at a facility where workers performed mechanical processing of cell phones, confirmed to contain beryllium alloy parts (total beryllium content in the processed material was measured as 52 ppm by weight). The investigators found that mechanical process operator exposures averaged 0.01 ug/m[3] during shredding (16 samples) and 0.02 ug/m[3] during milling and screening (i.e., sieving) (9 samples). Workers involved in shredding and milling tasks also performed sampling and housekeeping as part of their normal duties. Although these sample results were presented as summary information and so were not included in the exposure profile, they fully support the exposure profile shown in Tables IV-37 and IV-38.
Vincent et al. (2009) reported similar exposure levels during electronics waste dismantling activities in France, for which 23 partial-shift sample results indicated that worker beryllium exposures ranged from 0.004 ug/m[3] to 0.038 ug/m[3], with a median of 0.03 ug/m[3] (Vincent et al., 2009). Additional information is not available regarding worker activities or exposure controls, so this summary information from France is not included in the exposure profile.
Low exposures (typically 0.03 ug/m[3]) were also reported by a facility visited by ERG in 2005, where small parts of previously disassembled electronic devices are mechanically processed (by shredding, roasting, milling, screening, sampling, and housekeeping) to recover metal that is then shipped to the company's smelter for alloying (ERG Site Visit, 2005). All workstations are ventilated at this facility. Although exposure information from this facility is not included in the exposure profile, the summary information provided by ERG (2005), as well as Vincent (2009), fully supports OSHA's exposure profile for mechanical processing operators.
Furnace Operations Worker
The exposure profile for furnace operations workers is presented in Tables IV-37 and IV-38. This profile represents the best available exposure data. Furnace operations include roasting, sweating, melting, and casting activities performed by workers (and their helpers) that operate furnaces and incinerators. As shown in Table IV-37, the exposure profile is described by an overall median of 2.15 μg/m[3], a mean of 3.85 μg/m[3], and a range from 0.03 μg/m[3] to 14.08 μg/m[3]. The exposure profile includes two full shift samples from furnace operations workers in other (than beryllium) recycling and precious metal recovery. One result is less than 0.1 μg/m[3] and one result is greater than 0.2 μg/m[3] but less than or equal to 0.5 μg/m[3]. Due to the extremely limited number of full-shift samples for this job category (two) and the availability of several additional well-documented samples from the same facilities, OSHA has included in Tables IV-37 and IV-38 the results of four samples (listed below with sample durations) that are less than full shift. These samples were obtained from workers in the beryllium recovery and alloying application group. All are presented as TWAs for the period sampled, which exceeds 4 hours in each case.
Furnace Operations Workers Performing Beryllium Recovery and Alloying
Not surprisingly, furnace operations worker exposures are notably higher in the portion of the industry that specifically produces beryllium alloy than in the facilities where work with beryllium-containing materials is incidental to the primary activity (e.g., precious metal refining). OSHA's exposure profile in Table IV-37 illustrates this difference. During beryllium alloying operations (0.35 to 10.5 percent beryllium), four sample results for furnace operations workers ranged from 1.92 μg/m[3] to 14.08 μg/m[3] (mean 5.64 μg/m[3], median 3.28 μg/m[3]) (ERG Beryllium Site 7, 2003). Only one of the four sample results (25 percent) is (very slightly) less than OSHA's current PEL of 2 μg/m[3].
Considerable information is available on the working conditions associated with the samples in the exposure profile. For the workers alloying beryllium at ERG Beryllium Site 7 (2003), represented by three partial-shift sample results of 1.92 μg/m[3], 2.38 μg/m[3], and 4.18 μg/m[3] (all of durations of 252 minutes to 267 minutes) and one full-shift sample of 14.08 μg/m[3] (532 minutes), the primary exposure control in the facility is a canopy hood located over the furnace to capture fumes from the melt. Other sources of LEV include canopy hoods over casting stations, ingot conveyors, and dross buckets. The main hood covers the charge platform for the furnace and likely accounts for the high PBZ results for these workers; a closer examination of these data show that three of the sample results (1.92 μg/m[3], 4.18 μg/m[3], and 14.1 μg/m[3]) are associated with workers standing on the platform and directly in the path of the exhaust ventilation over the furnace (ERG Beryllium Site 7, 2003). Because of this design, these exposure results might not be representative of typical operating conditions in this industry. However, another source of exposure also existed, which might be more typical of the industry. The transfer of rubbing and skimming tools from the furnace is not ventilated (i.e., rubbing and skimming tools were fuming when they were removed from the furnace), and a significant number of 90-degree transitions were noted in the exhaust ducts (Corbett, 2005).
Furnace Operations Workers Engaged in Recycling and Precious Metal Recovery
The exposure profile shown in Tables IV-37 and IV-38 also lists two sample results (less than 0.03 μg/m[3] and 0.5 μg/m[3], with mean and median of 0.26 μg/m[3]) representing worker exposure during furnace operations in other recycling and precious metal recovery facilities (ERG Beryllium Site 2, 2003). At the facility where these samples were obtained, the thermal reduction unit is an enclosed gas-fired convection furnace that is ducted to an afterburner and baghouse filtration system. In the melting shop, canopy hoods are used to collect metal fumes generated during melting and casting operations. However, investigators observed visible emissions escaping the hoods (especially during pouring) and noted that major changes need to be made to bring the system into compliance with recognized standards for ventilation systems. A recommendation was made to utilize the services of an engineering firm to redesign the current layout of the LEV system to ensure that sufficient ventilation is always available (ERG Beryllium Site 2, 2003).
Summary information from other similar facilities also suggests that the sample results in OSHA's exposure profile are at the upper range of typical exposures for furnace operations workers and that this exposure profile might overestimate typical exposure levels in both the beryllium alloying and precious metals refining industries. A facility that mechanically processes electronic scrap for precious metals recovery operates a small furnace to produce sample batches of test alloy (100 pounds) for analytical purposes. This company reports that exposure levels for all employees throughout the facility are typically 0.03 μg/m[3] (ERG Site Visit, 2005). Kent at al. (2007) performed extensive air sampling in a precious metal recovery and refining facility that processes cellular telephones. These investigators found that, over 4 weeks of sampling, 18 PBZ full-shift sample results for furnace operations workers averaged 0.01 μg/m[3] during roasting and 0.05 μg/m[3] during alloying activities.
ERG also reviewed sampling results reported in OSHA's IMIS database to gain additional insight into the exposure profile of this job category (OSHA, 2009). The IMIS database (SIC groups 3341, 3399, and 4953) contains 219 PBZ samples (sample dates August 1979 to February 2001) for workers with job descriptions most consistent (i.e., not ambiguous) with furnace/incinerator operations (e.g., furnace operator, furnace helper, melter, incinerator operator, kiln operator, caster, stationary engineer, fireman, assistant and auxiliary operators, power attendant). Of these samples, 123 were positive for beryllium, with a mean of 32.5 μg/m[3], a median of 1.0 μg/m[3], and a range from 0.02 μg/m[3] to 3,671 μg/m[3]. However, 44 percent (97 samples) of these results are nondetectable, suggesting that the real median is significantly lower.
Together, both the background information available on the sample results used in the exposure profile and the additional sources of supporting exposure information (i.e., summary information not included in the exposure profile) suggest that the exposure profile might overestimate current exposure levels for furnace operations workers in the refining and alloying industry (ERG Beryllium Site 2, 2003; ERG Beryllium Site 7, 2003; ERG Site Visit, 2005; Kent et al., 2007; OSHA, 2009).
Technological Feasibility
Mechanical Processing Operator
Mechanical Processing Operator -- Baseline Controls
Based on the available data, ERG finds that mechanical processing operations typically are conducted with some level of automation, LEV, and partial or full enclosures, although the effectiveness of these controls can be less than optimal.
Mechanical Processing Operator -- Additional Controls
The preliminary median baseline exposure level for mechanical processing workers is 0.20 μg/m[3], and sample results for this job category range from less than 0.03 μg/m[3] to 0.2 μg/m[3] (see Table IV-37). An exposure level of 0.2 μg/m[3] or less has already been achieved for all workers in this job category through engineering controls (LEV) and work practices and administrative controls that keep processed scrap materials in enclosed equipment or areas served by LEV. To reach a level less than 0.1 μg/m[3], however, mechanical processing operators will require additional controls.
Effective Local Exhaust Ventilation and Process Enclosures
Manual processing operations can be conducted with minimal exposure to beryllium when the operations are equipped with effective engineering controls. For example, at ERG Beryllium Site 2, a 423-minute PBZ sample collected on the shredding process operator indicated a nondetectable beryllium concentration (less than 0.03 ug/m[3]). The shredding process operator loads cardboard containers of scrap electronic components (e.g., circuit boards, cell phone parts) onto a shaker table with a lift truck. Scrap is pulled from the shaker table onto a conveyor and transported through a sequence of steps that reduce the size of the scrap to (5/8)-inch pieces. The sequence includes a hammer mill, a shaker screen, a covered conveyor, a ring mill, a second shaker screen, and then a conveyor that transports the processed scrap to a collection box. The collection box fills every 7 to 10 minutes and is moved to a storage area once full. Other tasks completed by the shredding process operator include changing the shaker screen drum, changing the baghouse drum, housekeeping, and administrative duties. Engineering controls in the shredding department include partial or full exhausted enclosures on the hammer mill, ring mill, transfer conveyors, and screening stations. Investigators observed no visible emissions escaping the LEV systems in the shredding department.
Properly enclosing, sealing, and ventilating mechanical processing activities can be expected to significantly reduce worker exposures associated with these operations. Kent et al. (2007) reported on a facility where, to achieve average 8-hour TWA PBZ results of 0.01 μg/m[3] to 0.02 μg/m[3], ventilation was applied to the shredder, milling equipment, semi-automated product sampling equipment, and conveyer system drop/transfer points. They describe these ventilation systems as follows:
A 2,000 cubic feet per minute (CFM) dust collector ventilated the shredder. Partial enclosure and canopy style hoods were used on the shredder, product sampler and for elevation changes between conveyance systems. Capture velocities for these hoods ranged from 45-150 fpm. ...In milling, the ball mill charging hood, the sampler, and sampling drums were ventilated by a 3,000 CFM portable dust collector. Capture velocities for the partial enclosure style hood ranged from 180-200 fpm. ... [W]orkpractices used to reduce airborne dust levels included: cleaning of process equipment, floor cleaning with a sweeper/scrubber... (Kent et al., 2007).
Additionally, Kent et al. (2007) indicated that the facility reduced airborne dust levels through work practices such as routine cleaning of process equipment and cleaning floors with a power sweeper or scrubber. Using these controls, the investigators characterized beryllium exposure levels as "well-controlled" compared to the company's internal occupational exposure limit of 0.2 μg/m[3].
In the event that additional controls are still needed for mechanical processing tasks involving finely divided particles (i.e., high beryllium concentrations in the scrap, such as beryllium alloying dross), or the beryllium exposures are otherwise attributable to the handling or generation of powder-like materials, pharmaceutical quality powder handling systems may be able to reduce exposures to 0.1 ug/m[3]. These systems typically include: hood design and capture consistent with ACGIH design criteria; no open handling; glove boxes; totally enclosed processes; and material transport systems meeting zero leakage criteria (Naumann et al., 1996). For example, pharmaceutical-quality packing head systems are used for filling/weighing operations involving high-hazard powders. Packing head systems provide a sealed connection between the filling device and the container for dust-free transfer of product. Vented and extraction-type sealing heads are available for applications where container pressure must be avoided. Packing heads used in conjunction with laminar flow containment booths (containment isolator) further ensure operator safety during container filling. Or, as an alternative, containment booths can be used as secondary containment between two vessels during make-break operations. Typical applications for powder containment booths include large-scale dispensing, weighing, and product sampling (Absolute Control Systems, Inc., 2004; Hosokawa Micron Group, 2005). Additionally, customized double butterfly valves can be fabricated for applications where gas and dust-tight discharging of bulk materials is required in addition to stringent emission and leakage limits. According to one equipment manufacturer, pharmaceutical-quality high-containment powder and granule handling systems can achieve total dust control levels of 0.1 ug/m[3] or less (Hosokawa Micron Group, 2005).
Beryllium Content of Scrap
At a secondary copper smelting and refining operation (now closed), NIOSH investigators collected 50 PBZ samples (NIOSH HETA 82-024-1428). This facility performed the same type of refining and smelting operations represented in the exposure profile. Only five of the samples (10 percent) had detectable levels of beryllium, with concentrations ranging from 0.2 ug/m[3] to 0.5 ug/m[3]. These exposure concentrations were lower than those previously measured by the company. In the year immediately preceding NIOSH's visit, the company collected 127 airborne beryllium samples, with results that ranged from less than 0.1 ug/m[3] to 2.0 ug/m[3]. Seventeen percent (21 of 127) of the samples exceeded the NIOSH recommended standard of 0.5 ug/m[3]. NIOSH researchers attributed this variability in exposure primarily to the beryllium content of the furnace charge (with no additional discussion included in the report) and recommended that the company establish a policy to refuse all scrap that might be potentially contaminated with beryllium if adequate controls cannot be implemented to reduce beryllium exposures. Worker exposure to beryllium in smelting and refining operations can be eliminated or further reduced if the use of beryllium-containing scrap is eliminated or limited to scrap containing a low percentage of beryllium. For example, Noranda Recycling, Inc. has established a 200 ppm solid material limit and a 50 ppm dusty material limit for beryllium-containing scrap (Noranda, 2005). Noranda assays incoming scrap for its beryllium content and also requires suppliers to provide laboratory analysis reports. To deal with scrap that breaches Noranda's beryllium limits, the company has established a protocol that can include refusing to accept the scrap and suspending business with suppliers. These limits do not appear to eliminate the need for engineering controls and personal protective equipment but may limit the extent of exposures. Other control measures reportedly established and implemented by Noranda include but are not limited to: 1) a stringent code of practice for management of beryllium-containing materials; 2) employee training on standard operating procedures, with an emphasis on proper handling and processing; 3) employee education on the nature of beryllium exposure through seminars on beryllium awareness and surveillance; 4) an extensive industrial hygiene air sampling program; and 5) ventilation improvements at all affected smelting and recycling facilities (Noranda, 2000, 2003, and 2005).
Mechanical Processing Operator -- Conclusion
Based on the information contained in this analysis, OSHA preliminarily concludes that exposure levels of 0.2 ug/m[3] or less have already been achieved for the majority of mechanical processing operations most of the time through process enclosure, LEV, and semi-automated sampling equipment. This level has been achieved despite less-than-optimal LEV and process containment (investigators observed visible dust emissions from process equipment) (ERG Beryllium Site 2, 2003).
In the event that additional exposure reductions are necessary, these can be achieved by fully enclosing, sealing, and ventilating mechanical processing operations and ensuring that all LEV meets established design criteria (See Chapter 13 of ACGIH, 2010). Kent et al. (2007) reported on a facility that performs extensive mechanical processing of beryllium-containing electronic waste (confirmed to be 52 ppm beryllium by laboratory analysis). There, average exposure levels for mechanical processing operators were 0.01 ug/m[3] to 0.02 ug/m[3], suggesting that the vast majority of samples were well below 0.1 ug/m[3].
OSHA preliminarily concludes that both the proposed PEL of 0.2 ug/m[3] and an alternative PEL of 0.1 ug/m[3] can be achieved for the vast majority of mechanical processing operations most of the time.
Furnace Operations Worker
Furnace Operations Worker -- Baseline Controls
OSHA finds that baseline engineering controls for melting and casting workers at refining and alloying establishments typically include some level of automation, process enclosures (full or partial), graphite and inert gas blankets to minimize the formation of metal oxides, and LEV systems with baghouse filtration (Kent et al., 2007; ERG Site Visit, 2005). Furnaces, casting areas, and conveyors are typically ventilated. However, LEV systems frequently are less than optimal and in need of significant enhancement (e.g., increased exhaust flow and/or improved hood and ductwork design) (Kent et al., 2007; ERG Site Visit, 2005). Furthermore, certain processes are not fitted with LEV hoods and remain uncontrolled (e.g., furnace charging, slagging, tapping).
Other exposure controls typically available for melting and casting workers include company-provided work clothing and respiratory protection (Kent et al., 2007). Some facilities may have additional controls, including downdraft booths (air showers) to remove surface dust, change rooms, showers, and dedicated lunch/break room and hygiene facilities (Kent et al., 2007).
Furnace Operations Worker -- Additional Controls
The overall exposure profile median exposure level for furnace operations workers is 2.15 μg/m[3]. The atypical ventilation system conditions observed by ERG at Site 7 (workers standing directly in the furnace exhaust air stream) and other sources of information for similar operations suggest, however, that worker exposure may be overestimated for this job category (ERG Beryllium Site 7, 2003; Kent et al., 2007; ERG Site Visit, 2005). Thus, the overall median baseline exposure level is estimated to be less than 2.15 μg/m[3]. Furthermore, OSHA notes that the conditions of exposure differ for furnace operations workers at beryllium recovery and alloying facilities and those at facilities refining waste with a substantially lower beryllium content (e.g., electronic scrap). Therefore, OSHA has divided this job category into two subgroups representing furnace operations workers in these two portions of the industry.
Furnace Operations Workers Performing Beryllium Recovery and Alloying
The exposure profile for the subcategory of furnace operations workers in beryllium recovery and alloying facilities, provided in Tables IV-37 and IV-38, indicates that four sample results from one facility ranged from 1.92 μg/m[3] to 14.08 μg/m3 (ERG Beryllium Site 7, 2003). As described in the exposure profile discussion for this subgroup, however, due to the configuration of the furnace deck, at least three of the four samples were associated with workers standing within the path of the furnace exhaust air. Additionally, the method used to remove dross from the furnace resulted in some spillage outside the dross receptacle.
To reduce exposures associated with this job category, it will be necessary to take a multifaceted approach, combining a number of control options. Section 5 -- Nonferrous Foundries, of Chapter IV, Technological Feasibility, of the PEA -- describes how the foundry industry is able to reduce most furnace operator exposures to 0.5 ug/m[3] or less. In the foundry industry, workers also melt and cast metals, including alloys, ingots of special alloy blends, and metals with both high (in this case up to 5 percent) and lower (down to 1 percent) beryllium content. For the purposes of this analysis, OSHA finds great similarity between the equipment and alloying processes (and other melting and casting tasks) used in the foundry industry and those used in the smelting, refining, and alloying industry. Section 5 discusses additional controls for furnace operations workers, including a NIOSH workplace evaluation at a beryllium alloy foundry (NIOSH EPHB 326-16a, 2008) suggesting that exposure levels of 0.5 or less can be achieved for most foundry workers, including most furnace operations workers. The facility described in this NIOSH report has two foundry areas: 1) a green sand foundry, where workers use sand molds and cores for casting copper alloys of 1 percent to 4 percent beryllium; and 2) an ingot foundry using a permanent mold system to cast alloys up to 5 percent beryllium (during the sampling, workers cast aluminum alloy containing 2.5 percent beryllium). The ingot foundry process is essentially an alloying operation (in this case, performed in a foundry industry facility). Both of the foundries, however, offer control strategies useful to the smelting, refining, and alloying industry.
In both foundries, LEV systems are in place to remove fumes and dust associated with the furnaces, crucible transport (green sand foundry), pouring activities, and the dross barrels (all exposure sources in smelting, refining, and alloying facilities). In addition, the foundries (and cutting and grinding shop) are designated beryllium work areas with controlled access, personal protective equipment requirements, and processes in place to minimize beryllium migration to other facility areas. Housekeeping practices include the use of HEPA vacuums, and workers are responsible for cleaning and maintaining their work areas during the day and at the end of their work shift. Over two consecutive sampling dates, NIOSH collected a total of 17 PBZ full-shift beryllium samples at this facility.
NIOSH indicated that the melting and casting operation in the green sand foundry included six workers: one furnace operator, three molders, and two pouring operators. For workers in the green sand foundry, NIOSH investigators collected 12 samples that ranged from 0.03 ug/m3 to 0.58 ug/m[3] (including two nondetectable samples at 0.03 ug/m[3] and 0.04 ug/m[3]), with a mean of 0.17 ug/m[3] and a median of 0.11 ug/m[3] (NIOSH EPHB 326-16a, 2008). The supporting information available for the green sand foundry portion of this investigation does not link individual job categories or activities with these samples.  NIOSH did, however, note that the workers with greatest potential for overexposure in the foundry were associated with the melting and casting processes.
In the permanent mold casting foundry (referred to as ingot foundry above), four workers were involved with the process: two furnace operations workers who monitored the pouring of aluminum-beryllium alloy into the ingot molds, one worker who removed dross, and a worker who monitored the cooling process and conveyor to ensure that ingots were released from the molds and dropped into the ingot shoot. NIOSH collected five PBZ samples on workers in the ingot foundry. The results of these samples ranged from 0.03 ug/m3 to 0.55 ug/m[3], with a mean of 0.17 ug/m[3] and a median of 0.03 ug/m[3]. The two highest results (0.21 ug/m[3] and 0.55 ug/m[3]) were obtained on furnace operations workers. The remaining three results (each with a value of 0.03 ug/m[3]) were listed only as samples for workers in the ingot room, with no specific job category or activity linked to the individual samples (NIOSH EPHB 326-16a, 2008).
Although limited, these findings in both green sand and permanent mold casting foundries represent the best available information on well-controlled conditions during furnace operations involving alloys containing percentages of beryllium (in this case, 2.5 percent beryllium). Note that exposures to beryllium in sand and permanent mold casting foundries are similar since the operations are the same, except that sand molds are destroyed (to retrieve the cast) once a product is cast whereas a permanent mold is reused. See Section 5 -- Nonferrous Foundries, of Chapter IV of the PEA for a detailed discussion of foundries. These results show that all foundry workers in a melting and casting area, including the furnace operations workers, can achieve beryllium exposures of 0.55 ug/m[3] or less in foundries with effective engineering controls. Due to the similarities in equipment and processes between the foundry and alloying industry furnaces, OSHA believes that these findings apply equally to the furnace operations workers in the smelting, refining, and alloying industry.
Because beryllium tends to concentrate in dross from molten metal, use of lower beryllium alloys (e.g., less than 2 percent) does not directly translate to an equivalently lower exposure level; however, where the beryllium content is considerably lower than 2 percent, exposures could be somewhat lower than measured at this facility. For example, since the highest exposure for a foundry operator at a facility using higher beryllium alloys (at 2.5 percent) is 0.55 ug/m[3], the comparable worker in a foundry handling alloy with beryllium less than 2 percent could experience a modestly lower exposure level of, for example, 0.5 ug/m[3] most of the time.
Dross must be removed from the metal to improve alloy purity and therefore, the quality of the ultimate castings (Air Products, 2005). The Section 5 discussion of additional controls for foundry furnace operations workers also describes ventilation options for dross handling. Fully enclosing hoods provide the best fume capture. To minimize the challenges of maintaining adequate, consistent ventilation while workers access the furnace interior to remove dross, facilities that melt beryllium alloys need to design the fully enclosing hoods with trap doors to access the melt.
OSHA understands that purity specifications for certain alloys will require more rigorous dross removal and greater access to the furnace interior, which in turn could require different furnace control options. In these facilities, the primary option available to reduce exposures from this source is to remove the enclosing exhaust hood and replace it with an auxiliary ventilation system that can capture fumes and dust while providing access to the furnace. At the same time, to better capture fumes and dust from dross as the dross is transferred out of the furnace, foundries can incorporate a ventilation system extension or mobile arm that covers the entire path of the dross scoop, from the furnace to the ventilated receptacle. OSHA is not aware of a commercial source for a pre-constructed ventilation system with these characteristics; however, Materion Corporation has installed such a ventilation system over a furnace dross transfer point as part of a series of measures to control worker exposures to furnace emissions to levels of 0.5 μg/m[3] or less, and most exposures in the facility to 0.2 μg/m[3] or less (Materion Information Meeting, 2012). Experts agree that to fully control fumes from toxic metals, it is necessary to keep the entire process under LEV (CCMA, 2000; Corbett, 2005). Because retrofit foundry (including furnace) ventilation systems are often custom-designed, the lack of a commercial source is a less compelling concern than it might otherwise be. Recent advances in computer modeling offer enhanced methods for designing exhaust ventilation and for predicting the benefits of various configurations (NIOSH EPHB 233-133c; Huang et al., 2004; Heinonen et al., 1996).
Kent et al. (2007) measured 8-hour TWA PBZ beryllium levels during alloying operations for other metals (precious metals), where beryllium was also present as a low percentage (0.0052 percent, or 52 ppm) of the total metal. Because beryllium can be concentrated in the dross, however, the effective amount to which workers could be exposed might have been substantially greater (i.e., 2 to 50 times greater) but still perhaps not present in the concentrations encountered at a facility specifically producing beryllium alloys (DeYoung and Peace, 2009). Over multiple (three to five) charge/fluxing cycles and slag pours, beryllium exposure averaged 0.05 μg/m[3]. This metals recovery facility had installed a 16,000 cubic feet per meter (CFM) dust collector to ventilate five 24-inch diameter furnaces. Fumes from the furnace were captured close to the point of emission using side-draft slot-ring hoods (350 feet per minute [fpm] to 400 fpm) (Kent et al., 2007). Although the amount of beryllium in the recovered metal alloy was certainly considerably less than would be encountered in a smelting establishment working with common beryllium alloys, this example demonstrates that the industry also uses furnace ventilation systems that eliminate the opportunity possibility for workers to stand within the path of the exhaust air.
Furnace Operations Workers Engaged in Recycling and Precious Metal Recovery
As indicated in Table IV-37, OSHA obtained two results (less than the LOD of 0.03 μg/m[3] and 0.5 μg/m[3]) for furnace operations workers involved in recycling and precious metal recovery. One of the sample results exceeds 0. 2 μg/m[3], and additional controls will be required to reduce the remaining exposure levels to this level. The results were obtained in a facility where investigators noted visible dust emissions from process equipment (ERG Beryllium Site 7, 2003), meaning that ventilation was insufficient.
The primary control option to lower exposure levels involves upgrading or replacing existing ventilation systems to improve particulate capture. Lower full-shift PBZ exposure levels (averaging 0.01 μg/m[3] to 0.02 μg/m[3], and reliably 0.2 μg/m[3] or less) were obtained by Kent et al. (2007) in a facility where workers performed similar roasting, alloying, sampling, and housekeeping activities. At that facility, control technology included LEV at three points: at the roasting tray dumping station, in the alloying area on the melting furnace, in the dross/ingot pouring operation, and for the ingot de-scaling operation. Kent et al. (2007) described the engineering controls as follows:
A 125 CFM High Efficiency Particulate Air (HEPA) filtered vacuum ventilated an enclosure style hood used for the roast produce transfer. Face velocities for the hood ranged from 80-100 feet per minute (fpm).... A 16,000 CFM dust collector and ventilated five 24-inch diameter furnaces using closed capture side draft slot ring hoods. Centerline capture velocities for the exhaust hoods ranged from 350-400 fpm (Kent et al., 2007).
Additionally, a precious metal refining facility visited by ERG in 2005 reported achieving typical exposure levels of 0.03 μg/m[3] for all operations (including mechanical processing and furnace operations such as roasting, plus melting and casting samples of the processed material [batched in 100 lbs. of copper]). That facility had upgraded ventilation on the induction furnace in response to concerns about possible beryllium exposure (ERG Site Visit, 2005).
The ACGIH Industrial Ventilation Manual for Design provides examples of LEV hood designs for numerous metal melting furnace operations, including tilt and non-tilt furnaces, dross pots, pouring stations, fixed and mobile casting hoods, and others (see Group 13.55 in ACGIH, 2010). Hood design and capture consistent with ACGIH design criteria would be expected to significantly reduce exposures associated with melting and casting. Exhaust ventilation typically is required during metal melting furnace operations for metal oxide/fume control. For some applications, a single hood can be used for charging, melting, and pouring. Other applications may require a separate hood for furnace charging due to the type of charge or furnace. The skimming of dross prior to pouring is a potentially significant source of metal oxide/fume exposure and may require a separate exhaust system for metal oxide and/or dross control. Additionally, design specifications for LEV systems (i.e., hood design and exhaust flow) must take into consideration the increase in air temperature and the rapidly generated exhaust plume associated with metal purification (ACGIH, 2010 [see Group 13.55]).
Although no secondary copper smelters currently exist in the United States, and OSHA has no exposure information about secondary aluminum smelters or other nonferrous metal smelters that may operate in the United States, resources for controlling exposures in this portion of the industry are readily available. In addition to the information described above, which is relevant to a wide variety of furnace operations involving beryllium alloys, and the ACGIH Industrial Ventilation Manual for Design, OSHA offers an eTool for secondary lead smelters (OSHA Lead eTool, 2006). The eTool provides extensive guidelines (including LEV design criteria) for controlling metal dust and fume exposures associated with secondary smelting, including melting and casting operations. Although this eTool is specific to secondary lead smelters, it provides useful information applicable to this industry sector as a whole.
Beryllium Content of Scrap
As previously discussed, for some establishments, worker exposures might be eliminated or reduced if the use of beryllium-containing scrap is eliminated or limited to scrap containing a low percentage of beryllium. ERG visited a precious metal recovery facility that will not accept scrap with a beryllium content that exceeds 200 ppm (ERG Site Visit, 2005). At this facility, the raw materials are electronic waste (primarily circuit boards) and metals (such as copper scrap from manufacturing establishments. The company melts a portion of each batch of processed scrap for testing purposes (alloyed with 100 pounds of copper) and reports that monthly PBZ beryllium sampling shows that exposures throughout the facility are typically maintained at 0.03 μg/m[3].
Furnace Operations Worker -- Conclusion
The exposure profile, presented in Tables IV-37 and IV-38, shows that the median exposure level for all furnace operations workers is 2.15 μg/m[3]. OSHA has identified two distinct types of furnace operations:; those that conduct precious metal recovery and refining, and those that perform beryllium recovery and alloying. Two separate feasibility determinations are given below.
Furnace Operations Workers Engaged in Recycling and Precious Metal Recovery
OSHA preliminarily concludes that exposure levels of 0.5 ug/m[3] or less have already been achieved for those furnace operations workers engaged in recycling and precious metal recovery/refining (operations that tend to involve materials with low beryllium content). Though based on an extremely small sample, exposure levels of 0.2 ug/m[3] or less have already been achieved for half (50 percent) of those precious metal recovery/refining operations, and improvements to existing controls (e.g., repairing LEV systems, upgrading housekeeping) will likely reduce the exposure level of all furnace operations workers in this part of the industry to levels of 0.2 ug/m[3] or less. This conclusion is supported by observations in other facilities. A precious metal refining facility visited by ERG in 2005 reported PBZ beryllium exposure levels of 0.03 ug/m[3] for all workers in the facility. At another facility, over a 5-week period, Kent et al. (2007) collected 16 samples averaging 0.01 ug/m[3] for furnace operations workers performing roasting, and another 16 samples for furnace operations workers involved in precious metal alloying activities that averaged 0.05 ug/m[3] (with a statistical estimate that fewer than four samples per 100 samples might exceed the proposed PEL of 0.2 ug/m[3]). These results were achieved by installing a ventilation hood in the roasting tray dumping area and providing a 16,000 CFM dust collector for the five 24-inch diameter furnaces used for alloying (e.g., side-draft slot ring hoods with centerline capture velocities of 350 to 400 fpm) (Kent et al., 2007). OSHA preliminarily concludes that by using these methods, the proposed PEL of 0.2 ug/m[3] can be achieved for all of the furnace operations workers involved in precious metals recovery from mixed waste (e.g., electronic parts and components). Furthermore, an alternative PEL of 0.1 ug/m[3] can be achieved for most mixed waste recovery operations most of the time.
Furnace Operations Workers Performing Beryllium Recovery and Alloying
OSHA also preliminarily concludes that sample results of 0.5 ug/m[3] or less can be achieved for furnace operations workers performing beryllium recovery and alloying; however, these workers might continue to be exposed to levels above the proposed PEL of 0.2 ug/m[3] some of the time, and particularly when handling materials with elevated beryllium content (e.g., greater than 2.5 percent).
Based on current results for a well-controlled foundry with effective engineering controls (NIOSH EPHB 326-16a), OSHA preliminarily concludes that exposure levels of 0.5 ug/m[3] or less can be achieved for most furnace operations workers most of the time by installing LEV on the dross receptacle, improving (or rebuilding) LEV on furnaces if not yet installed, installing operator booths pressurized with filtered air, using HEPA filter vacuuming, and implementing beryllium migration policies such as having workers pass through air showers when exiting the furnace area to remove beryllium contamination on clothing. Exposures were below 0.5 ug/m3 for nearly all workers engaged in these furnace operations (including furnace operations workers, whose duties and equipment were similar to those in a smelting facility) at a beryllium alloy foundry visited by NIOSH (NIOSH EPHB 326-16a) where such controls were implemented. In that foundry, which has two casting areas, furnace controls for one furnace include a slotted hood above the furnace and a slotted hood with flexible hoses installed over the crucible. The second furnace (in another area of the same establishment) was equipped with both a slotted hood over the furnace pot and a canopy hood with canvas side extensions. OSHA preliminarily concludes that employers can achieve an exposure level of 0.5 ug/m[3] for all furnace operations workers engaged in refining and alloying beryllium by implementing the same set of controls (all components of this strategy must be used together). Even so, OSHA further preliminarily concludes that exposure levels of 0.2 ug/m[3] might not reliably be achieved for furnace operations workers refining and alloying beryllium, and therefore respiratory protection would be required.
The level of respirator required for furnace operators will be depend on the effectiveness of the controls.  Half facepiece respirators with an APF of 10 would provide sufficient protection for furnace operations workers for whom exposure levels have been reduced to a level of 2.0 ug/m[3] or less.  A powered air-purifying respirator with a loose fitting facepiece provides an APF of 25, which offers adequate protection for beryllium exposures up to 5.0 ug/m[3].  A powered air-purifying respirator or a supplied air respirator with a tight fitting full facepiece with an APF of 1000 would provide sufficient protection for exposure to levels as high as 200 ug/m[3].
Summary of the Technological Feasibility Findings for Secondary Smelting, Alloying, and Refining
OSHA identified two job groups in this application group with exposure to beryllium: mechanical process operators and furnace operations workers.  The exposure profile for the mechanical processing operator indicates low exposures (3 samples less than 0.2 μg/m[3]), even though these samples were collected at a facility where the ventilation system was allowing visible emissions to escape exhaust hoods.  Summary data from studies and reports published in 2005-2009 showed that mechanical process operator exposures averaged between 0.01 and 0.04 μg/m[3] at facilities where mixed or electronic waste including beryllium alloy parts were refined.  Based on these results, OSHA preliminarily concludes that the proposed PEL is already achieved for most mechanical processing operations most of the time, and exposures could be further reduced through improved ventilation system design and other measures, such as process enclosures.
As with furnace operations examined in other industries, the exposure profile showed considerably higher worker exposures for the furnace operator job category (six samples with a  median of 2.15 μg/m[3], and 83.3% above 0.2 μg/m[3]).  The two lowest samples in this job's exposure profile (0.03 and 0.5 μg/m[3]) were collected at a facility engaged in recycling and recovery of precious metals where work with beryllium-containing material is incidental.  At this facility, the furnace is enclosed and fumes are ducted into a filtration system.  The four higher samples, ranging from 1.92 to 14.08 μg/m[3], were collected at a facility engaged primarily in beryllium alloying operations, where beryllium content is significantly higher than in recycling and precious metal recovery activities and the furnace is not enclosed and workers are positioned directly in the path of the exhaust ventilation over the furnace.  OSHA preliminarily concludes that these exposures could be reduced by enclosing the furnace and repositioning the worker, but is not certain whether the reduction achieved would be enough to bring exposures down to the proposed PEL.  Based on the limited number of samples in the exposure profile and surrogate data from furnace operations, the proposed PEL may not be feasible for furnace work in beryllium recovery and alloying, and respirators may be necessary to protect employees performing these tasks.
References
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ACGIH, 2010. Sections 6.2 (Enclosing Hoods -- Introduction) and 6.3 (Totally Enclosing Hoods), Chapter 5 (Design Issues -- Systems), Chapter 13 (Specific Operations), and Section 8.9 (Selection of Air Filtration Equipment), Industrial Ventilation: A Manual of Recommended Practice for Design, 27th Edition. American Conference of Governmental Industrial Hygienists. Cincinnati, Ohio.
Air Products, 2005. Personal communication between Air Products and Chemicals, Inc., Allentown, PA, and Eastern Research Group, Inc. March 3.
Belmont Metals, 2005. Belmont Metals, Inc. website at http://www.belmontmetals.com. Accessed January 19.
Belmont Metals, 2001. Telephone conversation between Robert Henning of Belmont Metals and Eastern Research Group, Inc. November 19.
CCMA, 2000. Ventilation Control of Airborne Metals and Silica in Foundries. California Cast Metals Association (CCMA). El Dorado Hills, California. April.
CDA, 2003. The Copper-Base Scrap Industry and Its By-Products: An Overview. Copper Development Association, December 2003.
Cerro Copper, 2001. Telephone conversation between a representative of Cerro Copper and Eastern Research Group, Inc. November 13.
Corbett, M.L., 2005. Personal communications between Marc L. Corbett (consultant) and Eastern Research Group, Inc.
Cunningham, L. D., 2004. Beryllium Recycling in the United States in 2000. U.S. Geological Survey Circular 1196-P. October 14.
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EPA EIIP, 2001. Emission Inventory Improvement Program. Technical Report Series. Volume 2: Point Sources, Chapter 9 -- Preferred and Alternative Methods for Estimating Air Emissions from Secondary Metal Processing. U.S. Environmental Protection Agency. January.
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Hosokawa Micron Group, 2005. Telephone conversation between Eastern Research Group, Inc. and a technical representative from Hosokawa Micron Powder Systems, Summit, New Jersey. January 13. Product information is available at the following websites: http://www.hosokawa.com/web/Stott/ and http://www.hosokawa.com.
Huang, R., G. Liu, S. Lin, Y. Chen, S. Wang, C. Peng, W. Yeh, C. Chen, and C. Chang, 2004. Development and Characterization of a Wake-Controlled Exterior Hood. Journal of Occupational and Environmental Hygiene 1:769 - 778. December. KB Alloys, 2005. KB Alloys, Inc. website at http://www.kballoys.com. Accessed January 19.
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Lefgren, J., 2002. Telephone conversation between John Lefgren, President, Emron Metal and John L. Bennett, consultant to Eastern Research Group, Inc., January 31.
Materion Information Meeting. 2012. Personal communication during meeting between Materion Corporation and OSHA. Elmore, Ohio. May 8-9.
Milward, 2011. Introduction to Milward. Milward Alloys, Inc., Lockport, New York. Milward Alloys website at http://www.milward.com/intro.html. Accessed January 22.
Mulcahy, R., 2002. Telephone conversation between Rob Mulcahy, KB Alloys and John L. Bennett, consultant to Eastern Research Group, Inc., February 1.
Naumann, B.D., E.V. Sargent, B.S. Starkman, W.J. Fraser, G.T. Becker, and G.D. Kirk, 1996. Performance-Based Exposure Control Limits for Pharmaceutical Active Ingredients. American Industrial Hygiene Association Journal 57: 33 - 42.
NIOSH 85-116F. Glossary of Terms. In: Foundries -- Recommendations for Control of Occupational Safety and Health Hazards. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer. DHHS (NIOSH) Publication No. 85-116. September 1985.
NIOSH HETA 82-024-1428. Health Hazard Evaluation Report No. HETA 82-024-1428. Chemetco, Incorporated, Alton, Illinois. National Institute for Occupational Safety and Health, Cincinnati, Ohio. March 1984.
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NIOSH EPHB 233-133c. Control Technology and Exposure Assessment for Occupational Exposure to Crystalline Silica: Case 33 -- A Gray Iron Foundry with Computational Fluid Dynamics Used to Analyze an Existing Control and Model Proposed Modifications Report No. EPHB 233-133c. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Physical Sciences and Engineering. Cincinnati, Ohio. January 2002.
NIOSH EPHB 326-12a. Control Technology and Exposure Assessment for Electronic Recycling Operations, Elkton Federal Correctional Institution, Elkton, Ohio. Report No. EPHB 326-12a. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Cincinnati, Ohio. August 2008.
NIOSH EPHB 326-15a. Control Technology and Exposure Assessment for Electronic Recycling Operations, Unicor Marianna Federal Correctional Institution, Marianna, Florida. Report No. EPHB 326-15a. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Cincinnati, Ohio. October 2008.
NIOSH EPHB 326-16a. 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. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Applied Research and Technology. Cincinnati, Ohio. November 2008.
NIOSH EPHB 326-17a. Control Technology and Exposure Assessment for Electronic Recycling Operations, United States Penitentiary, Lewisburg, Pennsylvania. Report No. EPHB 326-17a. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Division of Applied Research and Technology, Cincinnati, Ohio. January 2009.
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Vincent R, et al. 2009. Occupational exposure to beryllium in French enterprises: a survey of airborne exposure and surface levels. Ann. Occup. Hyg., pp 1-10.
Warrenton Copper, 2001. Telephone conversation between Mike Gamble of Warrenton Copper and Eastern Research Group, Inc. November 13.

SECTION 6 -- SECONDARY SMELTING, REFINING, AND ALLOYING, APPENDIX 1 -- OVERVIEW OF SCRAP HANDLING PROCESSES AT AN ELECTRONICS RECYCLING FACILITY
The following description summarizes ERG's 2005 walk-through visit of an electronic waste recycling facility, addressed previously in this section on Secondary Smelting, Refining and Alloying. No personal or area sampling was conducted during the visit, but facility representatives informed ERG interviewers that employees are monitored for beryllium on a monthly basis. The company uses an 8-hour TWA action level of 0.1 μg/m[3] for PBZ samples but typically maintains exposure levels of 0.03 μg/m[3].
The facility receives and samples regular-grade electronic scrap (including circuit boards, integrated circuits, trim from circuit board manufacturing, connectors, and other electronic parts) prior to shipment to the company's smelter (at a different location) (ERG Site Visit, 2005). The firm also receives some metallic inputs, such as scrap from a copper punching operation. The non-electronic scrap represents only about 15 percent of its inputs. About 80 percent of the electronic scrap consists of circuit boards. The sample results determine the payment customers will receive for the precious metal content recovered from the shipments. The samples also identify hazardous constituents in the scrap and are used to determine whether the facility is willing to process the materials.
The facility will not accept scrap with beryllium that exceeds 200 parts per million.[,]  According to facility spokesmen, prospective customers are sometimes rejected if they fail (or are otherwise unable) to follow the facility's beryllium guidelines. Customers also often need to be educated about beryllium or beryllium oxide hazards when handling their scrap. Similarly, regarding all plant operations, the facility executives said that the company has directed them to do whatever is necessary to safeguard workers and that there is essentially no budget constraint on necessary safety and health expenditures.
This facility receives only small electronic components. Other facilities receive larger components and, in some cases, entire pieces of equipment (e.g., computers, printers). Beryllium metal is not generated in sufficient quantity, however, to be economically recoverable from this facility's processes. The company's smelter recovers gold, silver, palladium, platinum, and copper.
The facility employs 15 total production workers (referred to as "operators") divided over 2 shifts per day on 5 days per week or as necessary to meet demand, and 10 managerial and administrative personnel on the same division and schedule as production workers. Most operators can run all the equipment in the facility. The most skilled job is the operation of the induction furnace. Each shift has a shift leader and an assistant shift leader.
Processes employed at this facility include the following:
Receiving: All incoming materials must be packaged in Gaylord boxes (large cardboard boxes), 55-gallon steel drums, or 1-ton bags that have been securely strapped onto wooden pallets. During the visit, workers packaged incoming material in Gaylord boxes most of the time. The facility uses barcode lot identifiers and a computerized system to track its lots and schedule production.
Inspection: All lots are inspected in their packaging and then again on a conveyor prior to shredding/sampling to verify that the lot does not contain materials that pose a health, fire, or explosion risk. Prohibited materials include lithium batteries, nickel-cadmium batteries, mercury relays, Teflon-coated wire, polyvinyl chloride (PVC)-coated wire, and residual cyanide from gold stripping operations. Worker training covers the identification of prohibited materials, and examples of such materials are posted on a bulletin board along one of the main walkways in the facility. As noted above, the facility limits beryllium content to a maximum of 200 ppm. This level is based on what can safely be handled at the facility and the company's smelter. If a lot slightly exceeds this level, the facility might dilute the shipment's beryllium content rather than reject the lot.  Nevertheless, the facility executives suggested that the beryllium limits were strictly enforced. According to a description of the facility's operation, small quantities of prohibited materials will be removed prior to shredding, whereas large quantities can lead to rejection of shipments. The rejected material will then be returned to the customer facility at the company's expense. The executives noted that beryllium-free lots are rare, but about 25 to 30 percent of lots contain less than 10 ppm beryllium. Most lots contain less than 50 ppm beryllium.
Shredding: Approximately one half of all input materials are received pre-shredded  and others require shredding at the facility. Materials for shredding are emptied onto a shaking table and then conveyed to a 150-horsepower shredder where they are reduced to below 1.25 inches in diameter. Previously shredded materials enter the process flow at the point of the shredder discharge.
Sampling: Shredded material is conveyed to the top of the facility's rotary sampling machine where the primary sample is taken. The sample size is normally 2.5 percent to 5.0 percent of the lot, although this can vary for unusual lots or materials. The sample is always over 500 lbs to ensure that sufficient increments are taken to minimize the variance in sample results. The rotary sampler is designed to ensure that a representative sample of material is taken from the lots received. The primary sample is collected in steel drums and weighed. A reserve sample is collected at the same time and is stored in the warehouse. The bulk of the material is collected in Gaylord boxes and shipped to the company smelter. Dusts collected from the baghouse that serves both the shredding and sampling steps are weighed and sampled as well. A proportional dust sample is added to both the primary and reserve shredded material samples.
Roasting: The primary sample is then roasted in a tray furnace for 2 hours at 800°F to 1,200°F to remove volatiles, combust plastics, and embrittle circuit boards. The roasting renders the scrap friable and amenable to subsequent size reduction in a ball mill. The roasted material is removed from the oven, cooled, and weighed. The tray furnace has two primary chambers, two afterburner chambers, and one retention chamber to ensure that all volatiles are burned. The hot gases are air-cooled and then directed to the baghouse.
Ball milling: The roasted sample is milled for 30 to 45 minutes in a 4x5 ft ball mill. The mill is housed in a soundproof enclosure, and dusts generated from the loading and discharging are recovered and returned to the sample. The company enhanced ventilation for the ball mill when it upgraded the ventilation system in the late 1990s.
Screening: The pulverized sample from the ball mill is conveyed to a 5-ft vibrating Sweco screen. Two screens are used to separate the material into three fractions: (1/4)-inch + metallics, > (1/4)-inch and > 35 mesh metallics, and < 35 mesh "sweeps." The dusts collected from the ball milling and screening are also added to the "sweeps" fraction.
Sampling of Sweeps: The sweeps are blended in a Gemco blender for 20 minutes and discharged and sampled. The sample is split on a rotary splitter to between 400 and 800 grams. The sweeps sample is screened at 120 mesh, and any that is oversized is pulverized to minus 120 mesh in a ring mill. The minus 120-mesh fraction is then split into four portions of approximately 100 grams each.
Sampling of Metallics: An assay sample of the metallics is obtained by melting the metallics with copper to produce a uniform melt that gives a reproducible assay result. If the total weight of metallics exceeds 100 lbs, the >35 mesh and +1/4 inch metallics are melted separately. However, if the total weight of metallics is less than 100 lbs, the two fractions are combined for melting. Approximately 300 to 400 lbs of clean copper are melted in one of two induction furnaces, both of which are equipped with a fume ring (hood). The fume rings were custom-designed for the facility. The metallic sample, together with fluxes, is added to the melt, and the charge is heated until a uniform melt is produced. The slag is skimmed off, and pintube samples are taken of the melt. The melt is then cast into ingots and the ingots are weighed. The ingots are semi-spherical pieces that are then sent to the company smelter for further processing. For the pintube sampling, a worker uses a long-handled tool that clasps at the end of a set of narrow, glass pintubes. These are lowered into the melt, and the glass at the end of the tube is melted. Because the glass tubes are vacuum-sealed, the melting of the end causes the melt to rise into the tube. These portions can then be sampled.
Ventilation: All workstations are ventilated with hoods and/or partial enclosures, and the ventilation system is connected to two separate baghouses. The facility upgraded ventilation at the ball mill and induction furnace when the company became concerned about possible beryllium exposures.
Housekeeping: Operators do cleaning between lots and at the end of shifts. The facility has HEPA filter vacuums available for cleaning and performs monthly housekeeping inspections and periodic additional inspections. Housekeeping requires approximately 15 minutes per day. All operators participate. It takes workers approximately 2 minutes to vacuum themselves, and they must do so before leaving the production floor.
As noted earlier in this summary, company representatives indicated that they conduct monthly personal air monitoring for beryllium and find that the procedures described here typically maintain 8-hour TWA exposure levels in the range of 0.03 μg/m[3].

SECTION 7 -- PRECISION TURNED PRODUCTS
Industry Profile
An additional profile of the industry is available in Chapter III of this document.  The precision turned product manufacturing industry (NAICS 332721) includes companies that produce metal products by a combination of machining processes, including but not limited to turning, milling, tapping, drilling, sawing, and grinding. Beryllium-containing materials that might be used for these products include beryllium metal and beryllium alloyed with other metals, including copper, nickel, aluminum, magnesium, gold, and zinc (Kirk-Othmer, 1992).
Due to differences in the potential for worker exposure and the extent to which controls such as local exhaust ventilation (LEV) have already been implemented, OSHA has divided the industry into two groups: establishments that machine pure beryllium or alloys with a high beryllium content, and establishments that machine metal alloys with a low beryllium content.
Establishments using materials with a high beryllium content typically work with pure beryllium or aluminum-beryllium alloys, typically greater than 30 percent beryllium. Workers machine these materials primarily to produce parts for aerospace and other high-technology applications, including military aircraft, structural parts for missiles and satellites, optical systems, and X-ray windows.
Facilities that machine low-beryllium materials primarily work with copper-beryllium alloys (typically less than or equal to 2 percent beryllium), which are the most widely used forms of beryllium (U.S. Department of the Interior, 2002). Workers machine copper-beryllium alloys to produce resistance welding electrodes and other elements of electrode assemblies, aircraft parts (e.g., hydraulic systems), electronic components, battery posts for the automotive industry, and seals for the oil and gas industry (Affeldt, 2002; Akers, 2002; Capozzi, 2002; F&M, 2010; Parkinson, 2002; Schmidt, 2002). Additionally, copper-beryllium is used to manufacture injection molds for the plastics industry. While tool steel is the traditional material for this application, copper-beryllium is used for certain specialty molds. Copper-beryllium molds decrease warping and improve dimensional accuracy of the molded plastic part and decrease production cycle time (CDA, 1997; Sagar, 2000; Veitch, 2006). Beryllium-free copper molds were introduced as an alternative in the late 1980s, and one industry source reports that the trend is away from copper-beryllium and toward beryllium-free materials (Performance Alloys, 2002).
The number of establishments that machine pure beryllium or aluminum-beryllium alloys is very small due to the limited demand for beryllium parts and the difficulties of working with these metals; machining damages the surface of beryllium parts, so greater care or use of nontraditional machining techniques is required to limit damage.
Low-beryllium alloys (e.g., copper-beryllium alloys), on the other hand, are more easily machined and can be worked using conventional metalworking processes (Akers, 2002; Brush Wellman Guide, 2002). Nevertheless, based on industry sources, several factors constrain the number of establishments working with copper-beryllium. First, the market for machined copper-beryllium parts is small. Second, due to a combination of health concerns and the high cost of copper-beryllium, manufacturers have increasingly preferred beryllium-free materials (Affeldt, 2002; Performance Alloys, 2002). A number of contacts report they have stopped using copper-beryllium (Delvert, 2002; Plantenberg, 2002) or are using it in small quantities and only occasionally (Gray, 2002; Parkinson, 2002; Randolph, 2002). Most sources, including a contact at the National Machining and Tooling Association, believe that the number of machine shops working with copper-beryllium alloys represents a small percentage of the total number of machine shops, but could not provide a more accurate estimate the percentage (Akers, 2002; Nolan, 2002).
Based on the information discussed above, OSHA estimates that fewer than10 percent, or 312 of the 3,124 establishments in the precision turned products manufacturing industry, work with beryllium or its alloys. Based on discussions with representatives of two of the largest machining facilities of pure beryllium and aluminum-beryllium alloys, OSHA estimates that about 18 (5.9 percent) of these 312 establishments might work with pure beryllium or high-beryllium alloys (Facility A, 2002; Facility B, 2002). The Agency thus estimates that the majority of these 312 total establishments (294) work with low-beryllium alloys.
OSHA assumes that the size distribution of beryllium-using establishments is the same as the size distribution of all industry establishments. Therefore, these 312 establishments would be expected to employ 7,875 workers ((78,749/3,124) x 312 affected establishments). The 5.9 percent of these establishments using high-beryllium alloys yields an estimate of 465 (5.9% x 7,875) workers working with high-beryllium alloys, with the remaining 7,410 workers working with low-beryllium alloys.
Table IV-39 provides profile information for NAICS 332721 based on 2010 County Business Patterns data (U.S. Census Bureau, 2010).
Table IV-39 -- Number of Affected Establishments and Employees NAICS 332721 -- Precision Turned Products

                            Affected Establishments
                              Affected Employees
Facilities using high-beryllium content alloys
                                      18
                                      465
Facilities using low-beryllium content alloys
                                      294
                                     7,410
Total
                                      312
                                     7,875
Sources: U.S. Census Bureau, 2010; OSHA Office of Regulatory Analysis

Process Description
Precision turned products manufacturing facilities use a variety of metal forming equipment to machine and fabricate beryllium and beryllium alloy shapes, often for defense or aerospace applications. Machinists operate computer numerically controlled (CNC) mills, lathes, lappers, borers, grinders, and other metalworking equipment to process beryllium-containing material. Much of this equipment is automated and enclosed, but manual machining or electrical discharge machining (EDM) might also be performed. The metal pieces machined can vary in length from a centimeter to several meters (ERG Beryllium Site 1, 2002; ERG Beryllium Site 4, 2003; ERG Beryllium Site 9, 2004). Multiple pieces can be produced hourly or may require months and even years for completion, depending on complexity and size. Some pieces may be produced using a single machine, while others may require several processing steps on multiple machines. Additionally, multiple tool bits may be used during the machining cycle with a single machine, with the process periodically stopped to change bits. Figure IV-2 illustrates the plant layout of a precision machine shop that machines pure beryllium and high-beryllium alloys.
Machine shops working with low-beryllium alloys, such as copper-beryllium, use the same basic machining processes as those that work with other types of metals, and industry contacts report only minor differences in the types of equipment used to machine copper-beryllium and other metals.

Figure IV-2. Plant layout of a precision machine shop that machines
pure beryllium and high-beryllium alloys.
Production precision machining includes turning, boring, milling, planing, and grinding operations. The machinery used may be enclosed, partially enclosed, or not enclosed. Machining may be performed wet using a machining fluid, or dry. Industry experts suggest that most machine shops recognize the importance of ventilating beryllium-machining operations and typically utilize some type of LEV. Production machinery (such as CNC machining centers) may be enclosed, fully sealed, and exhausted.  Alternatively, a moveable exhaust duct can be manually positioned by the machinist to exhaust machining operations on partially enclosed or open machinery (ERG Beryllium Site 1, 2002; ERG Beryllium Site 4, 2003; ERG Beryllium Site 9, 2004).
Machinists are generally responsible for cleaning their equipment at the end of a work shift, but may also clean it during a machining cycle, between parts, after several parts have been machined, or midway through a work shift. Cleaning is conducted manually and includes removing metal scraps from the inside of the machine by hand or by using a vacuum or a small hand brush and dust pan, but might also include rinsing or dry wiping the machine inside and out (ERG Beryllium Site 1, 2002; ERG Beryllium Site 4, 2003; ERG Beryllium Site 9, 2004).
Affected Occupations
Machinists and other workers who operate machining equipment and perform related tasks have the greatest potential for beryllium exposure in this industry sector. Machinists working with pure beryllium, high-beryllium materials, and low-beryllium copper alloys all have some potential for beryllium exposure. In facilities that machine low-beryllium alloys, most employees in non-machinist jobs were found to have very low exposures, below 0.1 ug/m[3]. These jobs include maintenance workers (equipment and buildings), janitors, inspectors, shippers/receivers, and supervisors. Likewise, data and information presented in Appendices 7C and 7D indicate that exposures for most non-machinists in facilities machining pure beryllium or high beryllium alloys are also already below the alternative PEL of 0.1 ug/m[3].  Thus, although non-machining employees working with both high and low beryllium materials are potentially exposed to beryllium, because their exposure levels are already below 0.1 ug/m[3] employers would not be required to change existing protections for these employees, so they are excluded from the exposure profile and the discussion of technological feasibility that follows.
Number of Affected Workers
To estimate the total number of potentially exposed employees in the precision turned product manufacturing industry, OSHA used occupational employment data from the Bureau of Labor Statistics (BLS) 2008 Occupational Employment Statistics Survey (OES) (BLS, 2008). OSHA first matched OES occupational titles in the corresponding four-digit NAICS classification (3327) with at-risk jobs, and then summed the number of workers associated with each job title. OSHA calculated the percentage of total employment represented by each job title, and used these shares to project the number of employees in at-risk jobs, based on the estimated number of workers in facilities working with beryllium or its alloys in Table IV-39. These estimates are shown in Table IV-40.
Table IV-40 -- Estimates of Workers Potentially Exposed to Beryllium in the
Precision Turned Product Manufacturing Industry (NAICS 332721)
                           Employment by Occupation
                          Percent of Total Employment
                             Number of Employees*
Total Estimated Employment
                                    100.0%
                                     7,875
Total Estimated Production Employment (machining/non-machining)
                                     77.6%
                                     6,112
  Total Machining-Related Occupations:
                                     47.8%
                                     3,764
    Computer-Controlled Machine Tool Operators, Metal and Plastic
                                     7.5%
                                      591
  Numerical Tool and Process Control Programmers
                                     0.9%
                                      71
  Cutting, Punching, and Press Machine Setters, Operators, and Tenders, Metal and Plastic
                                     2.0%
                                      158
  Drilling and Boring Machine Tool Setters, Operators, and Tenders, Metal and Plastic
                                     1.3%
                                      102
  Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic
                                     2.3%
                                      181
  Lathe and Turning Machine Tool Setters, Operators, and Tenders, Metal and Plastic
                                     4.4%
                                      347
  Milling and Planing Machine Setters, Operators, and Tenders, Metal and Plastic
                                     1.8%
                                      142
  Machinists
                                     26.3%
                                     2,071
  Multiple Machine Tool Setters, Operators, and Tenders, Metal and Plastic
                                     1.3%
                                      102
        Total Non-Machining Related Occupations
                                     29.8%
                                     2,347
         Installation, Maintenance, and Repair Occupations
                                     2.5%
                                      197
         Other Production Occupations
                                     27.3%
                                     2,150
Non-Production Workers
                                     22.4%
                                     1,764
*	Estimated number of employees may not add up due to rounding.

Sources: BLS, 2008; Table IV-39

The BLS data suggest that 4,111 workers, or approximately 52.2 percent of employment at precision machining establishments, are associated with non-machinist occupations (197 workers in installation/maintenance/repair occupations plus 2,150 workers in other production operations and 1,764 workers in non-production occupations) (BLS, 2008). Prorated across the 312 affected establishments based on the number of establishments among the two segments of the affected industry, OSHA estimates that 250 non-machinists are employed at establishments that work with pure beryllium or high-beryllium alloys ((4,111 affected workers / 312 total establishments) x 19 establishments working with pure beryllium or high-beryllium alloys = 250 affected workers).  Using the same methodology, OSHA estimates that the remaining 3,860 non-machinists are employed at establishments that work with low-beryllium alloys.
Exposure Profile
To estimate the beryllium exposure profile in the precision turned product manufacturing industry, OSHA used individual full-shift personal breathing zone (PBZ) lapel sample results for machinists from several sources, including surveys from the National Institute for Occupational Safety and Health (NIOSH), exposure data from the U.S. Navy Environmental Health Center (NEHC), two ERG site visits to precision machining facilities, and case study reports from six facilities machining copper-beryllium alloys.[,] These data represent the best available exposure information for this industry analysis.
OSHA also reviewed published studies of precision machinists and other workers for exposure information (Martyny et al., 2000; Kelleher et al., 2001; Madl et al., 2007; and Johnson et al., 2001). However, the authors of these papers present only summary statistics no individual total beryllium PBZ lapel sample results were reported.  However, these papers do provide information on average exposure levels associated with various control methods.
Finally, OSHA reviewed exposure data from the Integrated Management Information System (IMIS) for beryllium (OSHA, 2009). As with all data obtained from IMIS, no additional information is available regarding the sampling or working conditions associated with these measurements. OSHA therefore used the IMIS analysis and the summary statistics from published studies only as supporting data in developing the exposure profile for the precision turned product manufacturing industry.
Data Sources
NIOSH Surveys
The NIOSH surveys include individual exposure data obtained for production machinists at four different establishments. All of the full-shift NIOSH data are used in the industry exposure profile. These surveys include the following sites:
A Small, High-Precision Machining Facility That Produces Components for Commercial and Military Applications
In 1976, NIOSH described this facility as a small, well controlled establishment. NIOSH collected one area sample and five PBZ lapel samples (two full-shift and three 15-minute samples) on production machinists manufacturing small pure-beryllium parts (NIOSH HHE 76-103-349, 1976). Machining operations at this facility included turning, drilling, boring, and milling. Each work station was equipped with a low-volume high-velocity LEV system. The capture velocity at the face of the intake hood was greater than 800 feet per minute (fpm), with velocities between 300 fpm to 500 fpm in a 4-inch radius around the cutting tools. No beryllium was detected in any of the samples; however, the per-sample LOD for beryllium was reported as 0.5 ug (individual sampling limit of detection (LOD) concentrations were not reported). OSHA calculated the estimated sampling LOD concentration of 0.52 ug/m[3] (LOD/sample volume) using the reported LOD and an estimate of the sample air volume (.96 m[3]).
Key observations noted by NIOSH investigators regarding this site include the following:
All beryllium work was conducted in a separate room called the Beryllium Room. The area was well labeled and contained washing facilities. Employees washed their hands before leaving the work area for breaks or to exit the building.
All employees were provided with clean uniforms on a daily basis. Uniforms and shoes were changed at the end of the day or whenever leaving the building. A shower was also present.
Work practices and handling of beryllium parts were good. For example, grinding small parts with an emery stick was done using an oil suspension so that beryllium dust did not become airborne.
General housekeeping in the plant was excellent. Periodic cleaning of the dust collection system was also conducted. The employee doing the cleaning was provided with a respirator approved for beryllium dust.
Employees appeared to be well informed of the hazards associated with beryllium and the required safety and health practices.
All employees received a thorough medical examination annually from a physician knowledgeable of their exposures to beryllium and possible health effects.
NIOSH investigators concluded that the facility was a good example of how a small company can provide a safe and healthy work environment for its employees. NIOSH recommendations included: 1) wearing safety glasses on a consistent basis; 2) not eating, drinking, or smoking in the Beryllium Room; and 3) providing a vacuum system for cleaning (NIOSH HHE 76-103-349, 1976).
The Former Rocky Flats Nuclear Weapons Plant in Golden, Colorado
NIOSH documented exposure levels at this facility in 1984, but collected little information on exposure controls. A total of 40 PBZ lapel samples were taken over a total of three shifts on two different sampling dates on production machinists milling beryllium parts presumed to contain pure beryllium and/or high-beryllium alloys (NIOSH HETA 84-510-1691, 1986). Results ranged from 0.08 ug/m[3] to 7.2 ug/m[3], with 14 of the results (35 percent) nondetectable for beryllium. Thirty-nine of the samples were full-shift; one was a partial-shift sample (210 minutes) and was not used in the exposure profile. Samples were collected and analyzed using NIOSH Method 7300, and the laboratory analytical limit of detection was reported to be 0.2 ug per sample. No information was provided about engineering controls or work practices in place during the exposure evaluation; however, NIOSH investigators recommended exhaust ventilation for all beryllium parts that are machined in the facility.
A Copper-Beryllium Machine Shop That Produces Connectors and Test Pins for the Electronics Industry
Exposure controls at this facility were described in a report by NIOSH's following a visit in 2008.  Five full-shift PBZ lapel samples were obtained on employees turning, grinding, polishing, and buffing copper-beryllium alloys (containing 2 percent beryllium) in the machine shop over two consecutive sampling dates (NIOSH EPHB 326-14a, 2008). One result was positive, with a value of 0.047 ug/m[3], and four of the results were reported as below the limit of detection, ranging from 0.016 ug/m[3] to 0.017 ug/m[3]. In addition to machinists, three PBZ samples were collected on quality control personnel. All three results were nondetectable for beryllium, with sampling LOD concentrations ranging from 0.015 ug/m[3] to 0.021 ug/m[3]. Air samples were collected and analyzed according to NIOSH Method 7300 (with modifications), and the estimated analytical reporting limit for this method was 0.005 ug per sample. Machining operations were enclosed and performed wet with metal-cutting fluids to minimize the release of airborne particles. The only source of LEV was a HEPA-filtered downdraft booth (6 feet high by 3 feet wide and 2 feet deep), vented outdoors, which was used on an intermittent basis to grind and buff small-diameter rods.
A Beryllium Alloy Foundry Including an Aluminum-Beryllium Permanent Mold Casting Area, a Separate Green Sand Casting Area for Copper-Beryllium, and a Machine Shop
This foundry produces ingots and a variety of copper-beryllium products (containing a maximum of 4 percent beryllium), including non-sparking hand tools. Six full-shift PBZ lapel samples were obtained in the cutting and grinding shop of the copper-beryllium green sand foundry (NIOSH EPHB 326-16a, 2008). All six samples were positive for beryllium with results ranging from 0.10 ug/m[3] to 1.07 ug/m[3]. Samples were collected and analyzed according to NIOSH Method 7300 (with modifications), and the estimated reporting limit for this method was 0.005 ug per sample. In the cutting and grinding shop, workers operated saws and grinders to remove excess metal from the castings produced in the foundry. Cutting and grinding activities were performed in enclosed and ventilated booths, and all workers were equipped with respiratory protection.
U.S. Navy Data
The U.S. Navy data include exposure data submitted by the Naval Environmental Health Center (NEHC) to the OSHA Beryllium Docket (OSHA-H005C-2006-0870-0144; OSHA-H005C-2006-0870-0145) and unpublished data OSHA obtained from the Navy Occupational Exposure Database (NEHC, 2000). These data represent PBZ lapel samples collected on workers machining copper-beryllium bushings and other beryllium-containing or potential beryllium-containing parts from 1987 to 2001. The Navy data include 45 PBZ samples taken during beryllium machining. Only six of the 45 results are based on full-shift sampling and are included in the exposure profile. These results range from 0.03 ug/m[3] to 0.46 ug/m[3] and include two samples nondetectable for beryllium (LOD concentrations reported as 0.08 ug/m[3] and 0.33 ug/m[3]). The samples were analyzed using either NIOSH Method 7102 or Method 7300, and the estimated LOD for both methods was 0.005 ug beryllium per sample. Other than a brief description of the machining task, no information is available about workplace conditions or exposure controls.
ERG Beryllium Site Visits
ERG conducted site visits to two different production machining facilities. One facility is referred to as ERG Beryllium Site 1 (ERG, 2002). This facility is small, with approximately 10 full-time employees, and it manufactures precision machined products from pure beryllium metal, high-beryllium aluminum alloy (primarily 60 percent beryllium), and other metals. The second facility, Beryllium Site Visits 4 and 9, manufactures products from pure beryllium metal, high-beryllium aluminum alloy (primarily 60 percent beryllium), and a beryllium metal/beryllium oxide matrix (also called Beryllium Metal-Matrix Composite, Beryllium-based MMC, or E-Material) (ERG Beryllium Site 4, 2003; ERG Beryllium Site 9, 2004; Materion MSDS M08, 2011; Martyny et al., 2000). The second facility was visited twice and is substantially larger than the first facility, with a high-volume production operation and a workforce in excess of 200 employees.
During its visits to the two facilities, ERG collected a total of 18 full-shift PBZ lapel samples that are included in the exposure profile, with results ranging from 0.02 ug/m[3] to 6.6 ug/m[3]. Seven of the 18 results are nondetectable for beryllium, with a sampling LOD of 0.02 ug/m[3]. The samples were analyzed by the OSHA Salt Lake Technical Center (SLTC) using OSHA Method 125-G, and the reporting limit for beryllium was 0.02 ug per sample. Although engineering controls varied depending on the task and the facility, the controls primarily included enclosed and ventilated machining centers, moveable operator-positioned LEV ducts, and partial enclosures with LEV.
The highest samples were values of 1.1 ug/m[3], 2.3 ug/m[3], 2.9 ug/m[3], and 6.6 ug/m[3]. The 1.1 ug/m[3] result was obtained on a worker machining 60 percent beryllium parts on two high-speed core grinders (ERG Beryllium Site 9, 2004). Two to three parts per shift were completed. The grinders were set to operate automatically, and once they were set in motion, the operator stood away from the grinders. The grinding was done wet, with machining fluid, and the grinders were partially enclosed and had exhaust ventilation. The elevated result suggests that the enclosure and/or exhaust ventilation might have been ineffective (perhaps due to the speed of the grinders) or that the adjacent surface grinding operation might have contributed to the worker's exposure (the adjacent surface grinding worker's exposure was 2.3 ug/m3 and is discussed below).
The 2.3 ug/m[3] result was obtained on a worker performing single-sided high-speed surface grinding on 60 percent beryllium parts (ERG Beryllium Site 9, 2004). The parts were placed in a lapper (surface grinder) for approximately one hour per cycle. During the hour, the operator stopped the lapper at various times to check on the progress of the parts. The grinding was performed under flood coolant with a partially enclosed LEV system. It is possible that the design of the exhaust ventilation and/or enclosure was insufficient for the speed of the grinder, because ERG investigators observed visible airborne coolant escaping the existing control system at high speeds. The investigators recommended fully enclosing the lapper.
The 2.9 ug/m[3] exposure result was obtained on a machinist grinding high-beryllium parts on two high-speed core grinders (ERG Beryllium Site 4, 2003). The grinding was done wet, using machining fluid, and the grinders were partially enclosed and had exhaust ventilation. It is possible that the exhaust ventilation on the grinders was inadequate, because ERG investigators noted that the design of some ventilation (especially in the department where the core grinders were located) might not be sufficient to ensure maximum collection efficiency. The investigators recommended redesigning the layout of the ventilation system. Additionally, because the operator stood away from the grinders during the machining cycle, this worker's exposure might have been affected by an adjacent operation.
The 6.6 ug/m[3] exposure result was obtained on a machinist operating an enclosed and ventilated double-sided lapper (ERG Beryllium Site 4, 2003). During the lapping cycle, the operator opened the machine four to five times to check on the progress of the parts. It is likely that this work practice increased the machinist's exposure. This assumption is supported by a NIOSH study that evaluated the ability of air filtering cleaners to control metalworking fluid mist emissions on partially enclosed machining centers used to produce transmission parts (NIOSH ECTB 218-12a, 1997). Through the use of video exposure monitoring with a direct-reading aerosol photometer, NIOSH investigators observed that peak exposures occurred when operators entered or partially entered the machining center enclosures. Other factors that might have contributed to the elevated beryllium exposure include the effectiveness of the machine enclosure and/or LEV as well as any adjacent contaminant-producing operations.
The published literature also contains reports with exposure data obtained from the larger precision machining facility surveyed by ERG (Kelleher et al., 2001; Madl et al., 2007; Martyny et al., 2000). These data (described below in the subsection on Machinists Machining Pure Beryllium and/or High-Beryllium Alloys -- Conclusion) were obtained prior to ERG's site visits; they supplement recent information obtained from the facility and make possible comparisons of exposures before and after various control measures were implemented.
Case Studies
OSHA obtained individual PBZ (lapel) total beryllium sample results for three precision machine shops processing copper-beryllium alloys (Brush Wellman Machining, 2004). Summary statistics for these data are available in the OSHA Beryllium Docket (OSHA-H005C-2006-0870-0097). These data include 63 full-shift and nine partial-shift results for machinists, and 30 full-shift results for non-machinists. Only full-shift results from the case studies were used in the beryllium exposure profile. The full-shift results for machinists range from 0.005 ug/m[3] to 24 ug/m[3], and 63 percent of the results (40 of the 63 samples) are nondetectable for beryllium (sampling LOD ranging from 0.005 ug/m[3] to 0.2 ug/m[3]). The non-machinist job categories include supervisor (not otherwise specified), shipper and receiver, inspector (machining), maintenance worker (equipment and building maintenance), and janitor. Eighty-seven percent of the PBZ results for the non-machinists (26 of 30 samples) are nondetectable for beryllium, with sampling LOD concentrations ranging from 0.005 ug/m[3] to 0.012 ug/m[3]. The four positive results include values of 0.006 ug/m[3], 0.008 ug/m[3], 0.021 ug/m[3], and 0.037 ug/m[3]. The analytical methodology was not specified for all the case study data; however, for most of the samples, NIOSH Method 7102 was used and the beryllium reporting limit was 0.005 ug per sample. Other than a job title and the type of beryllium machined, little information regarding workplace conditions and control technology is available for these data.
Three more recent copper-beryllium machining case studies from 2011 were also reviewed (Materion Corporation, 2011). The purpose of the studies was to characterize worker exposure to airborne beryllium and identify work practices and LEV controls necessary to maintain exposures consistently below a recommended exposure guideline of 0.2 ug/m[3]. These studies include the aggregated results of a baseline exposure evaluation (no individual sampling results available) and a description of the operating conditions and exposure controls.  In one of the studies, the machinists exposure results were consistently below 0.2 ug/m[3], and after LEV improvements were made, additional PBZ samples indicated that all exposures were below 0.1 ug/m[3] (Materion PSCS 102, 2011; Materion PSCS 103, 2011; Materion PSCS 104, 2011). OSHA used the information from these investigations to support the exposure profile and technological feasibility analysis for the precision turned product manufacturing industry. These studies include ram EDM (electrical discharge machining) and machining with CNC lathes and milling machining centers (Materion PSCS 102, 2011; Materion PSCS 103, 2011; Materion PSCS 104, 2011). In all, a total of 34 full-shift PBZ samples were collected, with results ranging from 0.007 ug/m[3] (nondetectable reporting limit) to 0.020 ug/m[3]. Because individual sampling results are not available, it is not possible to determine the number of nondetectable results. Nonetheless, all results are below 0.1 ug/m[3]. The CNC machining was done in enclosed machining centers with water soluble machining fluids (to lubricate and cool the cut and to flush away the turnings). No LEV was used. By contrast, the ram EDM was equipped with a manufacturer-supplied LEV system. A description of the LEV upgrades and cost information is included with the case study summary.
Other Published Studies
The published studies described below include three reports on the same large precision machining facility visited twice by ERG (Martyny et al., 2000; Kelleher et al., 2001; and Madl et al., 2007). These publications discuss aggregated exposure information for machinists and non-machinists at the respective facilities; no individual PBZ results are included. OSHA used these publications as supporting material to evaluate the effectiveness of engineering controls and supplement the exposure profile discussion with the information contained in these reports wherever possible.
Martyny et al. (2000)
This study reports 64 beryllium PBZ lapel samples (as well as other types of samples) collected on machinists from June 1996 to February 1997 at a well-studied precision machining facility (ERG Beryllium Site 4 and Site 9). The investigators looked at five mechanical processes typically used to machine beryllium, including milling, lathing, deburring, lapping, and grinding (Martyny et al., 2000). The beryllium samples were collected over two shifts and are characterized by a mean of 1.48 ug/m[3], a median of 0.29 ug/m[3], and a range from 0.03 ug/m[3] to 41.48 ug/m[3]. The median exposure concentration by type of machining was as follows: 0.10 ug/m[3] (lapping); 0.20 ug/m[3] (milling); 0.26 ug/m[3] (grinding); 0.40 ug/m[3] (lathing); and 0.57 ug/m[3] (deburring). The number of nondetectable samples was not disclosed. Most samples were analyzed using NIOSH Method 7300, which had a LOD of 0.007 ug per sample and a limit of quantitation (LOQ) of 0.030 ug per sample. A limited number of samples (number unspecified) were analyzed using NIOSH Method 7102. This method had a LOD of 0.0003 ug per sample and a LOQ of 0.005 ug per sample. Results below the LOD were assigned a value of one-half the method LOD for the purposes of statistical analysis. Martyny et al. noted that the machinists adjusted their own ventilation control devices (i.e., LEV) and that these devices may not have been positioned as effectively as possible for each machining process evaluated.
Kelleher et al. (2001)