Evaluation of Potential 

Exposures at an Electrolytic 

Manganese Dioxide 

Processing Plant 

Srinivas Durgam, MSPH, MSChE, CIH

Carlos Aristeguieta, MD, MPH

Health Hazard Evaluation Report

HETA 2007-0331-3100

Erachem Comilog, Inc.

New Johnsonville, Tennessee

January 2010

Department of Health and Human Services

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific 

facility evaluated and may not be universally applicable. Any recommendations made are not to be 

considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE 

reports are available at http://www.cdc.gov/niosh/hhe/
The employer shall post a copy of this report 

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

period. [37 FR 23640, November 7, 1972, as 

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2007-0331-3100 Page i

Appendix A

Report Abbreviations.......................................................................ii

Highlights of the NIOSH Health Hazard Evaluation............ iii

Summary .............................................................................v

Introduction..........................................................................1

Assessment.........................................................................4

Results.................................................................................7

Discussion .........................................................................11

Conclusions.......................................................................15

Recommendations.............................................................15

References ........................................................................19

Contents

Tables ................................................................................29

Methods.............................................................................22

Appendix B Occupational Exposure Limits & Health Effects ................23

Appendix C

Acknowledgments and Availability of Report.....................35 Acknowledgments
Page ii Health Hazard Evaluation Report 2007-0331-3100

ACGIH® American Conference of Governmental Industrial Hygienists

AL Action Level

CCO Certified chemical operator

CFR Code of Federal Regulations

dBA Decibels, A-scale

EMD Electrolytic manganese dioxide

GA General area

HEPA High-efficiency particulate air

HHE Health hazard evaluation

IARC International Agency for Research on Cancer

mg/m3 Milligrams per cubic meter

MDC Minimum detectable concentration

MQC Minimum quantifiable concentration

NAICS North American Industry Classification System

ND Not detected

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PAPR Powered air-purifying respirator

PBZ Personal breathing zone

PEL Permissible exposure limit

PPE Personal protective equipment

ppm Parts per million

REL Recommended exposure limit

STEL Short term exposure limit

TLV® Threshold limit value

TWA Time-weighted average

WEEL Workplace environmental exposure level

Abbreviations
Health Hazard Evaluation Report 2007-0331-3100 Page iii

Highlights of the

NIOSH Health

Hazard Evaluation

The National Institute 

for Occupational Safety 

and Health (NIOSH) 

received a health hazard 

evaluation request 

from a representative 

of the International 

Union of Operating 

Engineers Local 369 at 

Erachem Comilog, Inc., 

in New Johnsonville, 

Tennessee. The requestor 

was concerned about 

exposure to cobalt and 

nickel in the filter mud, 

manganese dust in the 

production areas, and 

acid mist in the cell 

rooms. The health effects 

reported were cancer, 

lung problems, skin and 

eye irritation, nausea, and 

exhaustion.

What NIOSH Did

● We conducted site visits in October 2007 and February and 

August 2008.

● We looked at the work processes and practices used to 

produce electrolytic manganese dioxide.

● We collected air samples to evaluate employee exposures to 

manganese, cobalt, nickel, and sulfuric acid.

● We assessed whether employees’ symptoms were related to 

their workplace exposures.

● We observed employees’ use of personal protective 

equipment.

● We reviewed the company’s respiratory protection and 

hearing conservation programs.

What NIOSH Found

● Two employees’ full-shift personal breathing zone air 

samples for manganese exceeded the NIOSH recommended 

exposure limit, and 16 exceeded the American Conference of 

Governmental Industrial Hygienists threshold limit value.

● One short-term personal breathing zone air sample for 

manganese collected during bagging of the final product 

exceeded the American Conference of Governmental 

Industrial Hygienists excursion limit.

● Employees were not overexposed to cobalt, nickel, or sulfuric 

acid.

● Two employees with cancer were identified in medical 

interviews. One employee had cancer of the lymph nodes 

and another had cancer of the throat.

● Health effects such as lung disease, skin and eye irritation, 

nausea, and exhaustion were reported in the request, but 

employees neither mentioned them in medical interviews, 

nor in conversation with other NIOSH investigators.

● The written respiratory protection and hearing conservation 

programs did not identify which work tasks require personal 

protective equipment or the type of personal protective 

equipment employees should wear.

● Cell room employees were at increased risk of work-related 

injuries such as falls and thermal and chemical burns. 

Poor visibility, lack of barriers, and uncovered cell tanks 

contributed to the increased risk.
Page iv Health Hazard Evaluation Report 2007-0331-3100

Highlights of the

NIOSH Health

Hazard Evaluation

(continued)

What Managers Can Do

● Use engineering controls such as installing local exhaust 

ventilation for the bag filling operation to reduce dust 

generation.

● Provide a minimum of a NIOSH-approved half-mask air 

purifying respirator with N95 or higher filter efficiency for 

daily wear to employees with job titles whose exposures 

exceed the manganese occupational exposure limits until the 

engineering controls are implemented.

● Conduct air sampling to identify additional job tasks that 

may exceed the manganese occupational exposure limits.

● Improve housekeeping in control rooms and throughout 

the production floor to decrease the amount of dust that 

becomes airborne. For example, use vacuum cleaners 

equipped with high-efficiency particulate air filters for 

cleaning instead of dry sweeping.

● Use nonreactive fiber-reinforced plastic covers to reduce acid 

mist and steam from the cell tanks. These covers should 

reduce fogging and improve visibility in the cell rooms.

● Cover empty cell tanks or place barricades along the full 

length of the cell tank to prevent employees from falling into 

cell tanks. Employees could also use crane-mounted, fixed/

extendable walkways when working in cell rooms.

● Revise the written respiratory protection and hearing 

conservation programs to identify job tasks, job locations, 

and type of protection required.

● Refer employees with work-related health concerns to an 

occupational health physician.

What Employees Can Do

● Use the existing local exhaust hoods in the maintenance 

shop when cutting and grinding metal.

● Be aware of safety hazards when working in the cell rooms.

● Tell your supervisor if you have health problems or concerns 

related to work. Seek medical care from an occupational 

health physician for work-related health concerns.
Health Hazard Evaluation Report 2007-0331-3100 Page v

Summary

NIOSH evaluated 

exposures to manganese, 

cobalt, nickel, and sulfuric 

acid. Some employees’ 

manganese exposures 

exceeded the NIOSH 

REL, ACGIH TLV, or 

ACGIH excursion limit. 

Exposures to cobalt, 

nickel, and sulfuric acid 

were low. We recommend 

installing a local exhaust 

hood for the bag filling 

operation, covering 

cell tanks, and warning 

employees of possible 

fall hazards in order to 

reduce employee injuries. 

Employees with job titles 

that exceed the OELs for 

manganese should wear 

a minimum of a NIOSHapproved N95 half-mask 

air purifying respirator 

until engineering controls 

reduce exposures below 

the OELs.

NIOSH received an HHE request from a representative of the 

International Union of Operating Engineers Local 369 at Erachem 

Comilog, Inc., in New Johnsonville, Tennessee. The requestors 

were concerned about exposure to cobalt and nickel in the filter 

mud, manganese dust in the production areas, and sulfuric acid 

mist in the cell rooms. The health effects reported were cancer, 

lung problems, skin and eye irritation, nausea, and exhaustion. We 

conducted site visits in October 2007, February 2008, and August 

2008.

On October 24–25, 2007, we toured the facility to observe work 

processes, work practices, and PPE use. Confidential medical 

interviews were conducted with 11 employees, and 4 PBZ air 

samples were collected for sulfuric acid. We reviewed previous air 

sampling records, injury and illness records, and the respiratory 

protection and hearing conservation programs. During the 

February 20–22, 2008, site visit, we collected 16 full-shift PBZ air 

samples for sulfuric acid and 13 full-shift PBZ air samples for dust 

to evaluate employee exposure to metals such as manganese, cobalt, 

and nickel. We also conducted task-based air sampling by collecting 

four PBZ air samples for metals on employees performing job tasks 

associated with dropping and drumming the filter mud and spray 

washing the filters. During the August 25–28, 2008, site visit we 

collected 50 full-shift PBZ air samples, 2 full-shift GA air samples, 

and 3 task-based air samples for dust-containing metals over the 

morning and night shifts.

We found that 2 PBZ air samples for manganese exceeded the 

NIOSH REL of 1 mg/m3, and 16 exceeded the ACGIH TLV of 

0.2 mg/m3. The highest PBZ concentrations of manganese were 

among operators working in the product preparation area, ore 

trammers, and CCOs in the digest area of the plant. Of the 33 

PBZ air samples collected from employees (CCOs and product 

preparation operators) working 12-hour shifts, seven exceeded 

the ACGIH TLV of 0.2 mg/m3. However, if the ACGIH TLV for 

manganese is adjusted to account for the 12-hour work shifts, 16 

PBZ air samples would have exceeded the adjusted TLV of 0.1 

mg/m3. In addition, a 30-minute task-based sample collected when 

an employee was bagging the final product exceeded the ACGIH 

excursion limit of 0.6 mg/m3. Employees’ full-shift and task-based 

exposures to cobalt, nickel, and sulfuric acid were very low and 

below their applicable OELs. We also found that the respiratory 

protection and hearing conservation programs had deficiencies. 

The written respiratory protection program did not accurately 

reflect actual employee PPE use.
Page vi Health Hazard Evaluation Report 2007-0331-3100

Summary (continued)

Interviewed employees were concerned about cancer risk, upper 

airway irritation from exposure to sulfuric acid mist, and safety 

when working in cell rooms. Four out of 11 employees reported 

nosebleeds when exposed to the sulfuric acid mist. Review of the 

OSHA Form 300 Log of Work-Related Injuries and Illnesses for 

the years 2002–2007 showed entries for chemical and thermal 

burns, falls, and musculoskeletal injuries such as sprains and 

strains. We found no cases of chronic manganese, cobalt, or nickel 

poisoning.

We recommend installing local exhaust hoods for the bag filling 

operation and using existing local exhaust hoods when cutting 

and grinding parts. We recommend that employees with job titles 

exceeding the OELs for manganese wear a minimum of a NIOSHapproved half-mask air purifying respirator with N95 or higher 

filter efficiency until engineering controls reduce exposure below 

the OELs. We also recommend using nonreactive fiber-reinforced 

plastic covers to reduce the amount of acid mist and steam 

generation. Until the plastic covers are installed, management 

should place barricades along the full length of the cell tank to as a 

warning and to prevent employees from falling into the cell tanks. 

Employees could be also provided with crane-mounted fixed/

extendable walkways to conduct their job safely in cell rooms. 

Additionally, we recommend revising the written respiratory 

protection program to address inconsistencies between the written 

program and the employees’ current respirator use.

Keywords: NAICS 325188 (All Other Basic Inorganic Chemical 

Manufacturing), manganese, sulfuric acid, manganese dioxide, 

EMD, battery, cell
Health Hazard Evaluation Report 2007-0331-3100 Page 1

Introduction

In August 2007, NIOSH received an HHE request from 

a representative of the International Union of Operating 

Engineers Local 369 at Erachem Comilog, Inc. (Erachem) in New 

Johnsonville, Tennessee. The requestor was concerned about 

exposures to cobalt and nickel in the filter mud, manganese dust 

in the production areas, and sulfuric acid mist in the cell rooms. 

The health effects reported were cancer, lung problems, skin and 

eye irritation, nausea, and exhaustion. We visited the plant from 

October 24–25, 2007, to learn more about the manufacturing 

process, observe work practices, conduct an initial environmental 

evaluation, and review pertinent records. We returned on February 

20–22, 2008, to evaluate employee exposures to sulfuric acid mist 

and perform a limited evaluation of dust exposures. A final site 

visit was conducted from August 25–29, 2008, to evaluate exposure 

to three metals, manganese, cobalt, and nickel.

Background and Process Description 

Erachem is major producer of high purity EMD, which is used to 

make primary batteries or alkaline cells. The New Johnsonville 

plant was constructed in 1967 and operates 24 hours per day, 

7 days per week. Erachem has approximately 94 production 

employees who fall into the following categories: CCOs and a 

product preparation operator (12-hour shifts, 3 or 4 days a week 

starting at 0600 hours); harvesters (three 8-hour work shifts, 7 

days a week starting at 0600 hours); and ore trammers, mechanics, 

laborers, and electricians (two 8-hour shifts, 5 days a week starting 

at 0600 hours). Erachem has a safety committee that meets 

quarterly and includes union and management representatives.

EMD manufacturing consists of five main processes: ore 

preparation (includes ore tramming) and ore reduction, digestion, 

purification, electrolytic deposition of EMD, and product 

preparation. In ore preparation, a front bucket loader transports 

raw ore (containing manganese dioxide and other metal impurities) 

and coal from separate storage pads to a bucket hopper. Ore and 

coal are conveyed separately to a crusher where they are dried and 

ground to size. In the ore reduction process, ground ore and coal 

are fed to reduction furnaces where carbon dioxide produced 

from the combustion of coal acts as a reducing agent, converting 

manganese dioxide in the ore to manganous dioxide. In the 

digestion process, manganous dioxide (which is more acid soluble), 

is combined in the digest tanks with sulfuric acid. Contaminants 
Page 2 Health Hazard Evaluation Report 2007-0331-3100

Introduction 

(continued) are precipitated, and the process stream is filtered to remove solid 

wastes. The filtrate and overflow from digest tanks is filtered for a 

second time and is used for the purification process.

In the purification process, metals such as cobalt and nickel are 

precipitated in their sulfide forms. The solution is clarified and 

filtered and used as a cell feed in the electrolytic cells tanks. Cobalt 

and nickel sulfide solids from the filtration process, called the 

“filter mud” are removed by spray washing the filters. The filter 

mud is collected in 55-gallon drums arranged on a wooden palette, 

which is raised by forklift to protect the employees from splashes as 

the mud is being dropped from the floor above. On average, twenty 

55-gallon drums are filled in a single filter mud drop operation. 

Employees shovel the excess filter mud to fill the drums before 

sealing them for transport. The filter mud drop operation takes 

approximately 6–8 hours to complete.

Electrolytic deposition is conducted in electrolytic cell tanks that 

contain alternating copper cathodes and titanium anodes. A 

manganese sulfate stream coming from the purification process 

acts as the cell feed; hot steam keeps it at near-boiling temperatures. 

The cells’ liquid surface is covered with polypropylene beads that 

facilitate steam condensation and reduce acid mist generation. The 

manganese dioxide is allowed to plate on the anodes for 3 weeks. 

The plated EMD is stripped from the anode with rotating rubber 

hammers. The EMD chips are collected in a hopper or dropped on 

a moving conveyer, and then they are segregated and stored in an 

open area called chip pads. In the product preparation operation, 

a compact front-end loader transfers the EMD chips to the jaw 

crusher (chip tramming), where they are reduced in size and 

transferred to a roller mill. The milled EMD is mixed with sodium 

hydroxide to remove residual acidity. Excess liquid is removed with 

a vacuum-enhanced belt filter, and the filter cake is dried in a flash 

dryer. The final product is bagged into sacks that can weigh up to 

3,000 pounds. A large axial fan (mounted on the building exterior 

wall approximately 5 feet away from the bagging station) provides 

general exhaust ventilation during the bagging process (Figure 1).
Health Hazard Evaluation Report 2007-0331-3100 Page 3

Introduction (continued)

Erachem has two buildings, each with two cell rooms. Each cell 

room has approximately 30 cell tanks for the electrolytic deposition 

process. These buildings have two open sides that can be covered in 

winter with polymer tarps to conserve heat or opened in summer 

to facilitate natural ventilation (Figures 2 and 3).

Axial

Fan

Figure 1. Bagging process – without local exhaust ventilation. 

Figure 2. Cell room side view – without tarp in October 2007. 
Page 4 Health Hazard Evaluation Report 2007-0331-3100

Introduction 

(continued)

Employees can volunteer to receive an annual physical examination 

and can decide on the components of their examination, which 

is paid for by Erachem but done at their private physician’s 

office. The company conducts annual respirator fit testing and 

audiometry and biannual spirometry on all employees.

During our initial environmental evaluation October 24–25, 2007, 

we toured the plant and observed work processes and PPE use. We 

collected four full-shift PBZ air samples for sulfuric acid in the cell 

rooms. We interviewed employees about work-related health effects 

and concerns. We also reviewed the following documents:

● Company air sampling report dated October 4, 2007

● Noise sampling report dated August 11, 2006

● Respiratory protection and hearing conservation programs

● OSHA Logs for the years 2002–2007

Employees informed us that fogging greatly reduced visibility in 

the cell rooms during winter; they were concerned that acid mist 

exposures were higher during winter when there is less natural 

ventilation (Figures 4 and 5). Additionally, they were concerned 

about potential chemical hazards resulting from dissolution of the 

polypropylene beads. These beads are used to reduce evolution 

Assessment

Figure 3. Cell room side view – partially covered with tarp in February 2008.
Health Hazard Evaluation Report 2007-0331-3100 Page 5

Assessment (continued) of acid mist and steam from the cell tanks. They also mentioned 

that dust levels were high during ore and EMD chip tramming 

operations especially in the summer (Figure 6). Because of different 

concerns during different seasons of the year, we made additional 

site visits in February 2008 to evaluate exposures to sulfuric acid 

mist and metals and in August 2008 to evaluate exposures to three 

metals, manganese, cobalt, and nickel.

Figure 5. Visibility inside cell room in February 2008 (side of room 

 covered with tarp). 

During our site visit in February 2008, we collected 16 fullshift PBZ air samples for sulfuric acid to assess exposures of cell 

harvesters working in the cell rooms, as well as cell room CCOs. 

Figure 4. Visibility inside cell room in October 2007 (side of room partially 

 covered with tarp).
Page 6 Health Hazard Evaluation Report 2007-0331-3100

Assessment (continued)

We also collected 13 full-shift PBZ air samples (five on CCOs, 

seven on mechanics, and one on a laborer) to evaluate employee 

exposure to manganese, cobalt, and nickel. We collected four PBZ 

task-based air samples for the same metals on employees dropping 

the filter mud, including spray washing the filters and filter mud 

drumming. During this visit, employees expressed concern about 

exposure to hydrogen sulfide gas generated during the digest and 

purification processes.

During our site visit in August 2008, we collected 50 full-shift PBZ 

air samples and 3 task-based PBZ air samples over the morning and 

night shifts for manganese, cobalt, and nickel. We also collected 

two full-shift GA air samples in the filter building control room, 

which is occupied by the digest and purification CCOs who 

monitor the digest and purification processes and do quality 

checks on the digest filtrate. We collected two PBZ task-based air 

samples for the same metals when employees were bagging the final 

product and tramming ore. We conducted PBZ air sampling for 

hydrogen sulfide on CCOs working in the digest and purification 

areas of the plant. We used Toxi Ultra single sensor gas detectors 

(Biosystems, Middletown, Connecticut) for hydrogen sulfide gas 

concentration measurement with an alarm set-point at 30 ppm 

(OSHA ceiling limit is 20 ppm).

Details on the methods used in this evaluation for sulfuric acid, 

manganese, cobalt, and nickel are explained in Appendix A. The 

OELs and potential health effects for these chemicals are discussed 

in Appendix B.

Figure 6. Tramming EMD chips with front end loader – open cab.
Health Hazard Evaluation Report 2007-0331-3100 Page 7

Detailed PBZ and task-based air sampling results for sulfuric acid, 

manganese, cobalt, and nickel along with the applicable OELs are 

presented in Appendix C.

During the October 2007 visit, the PBZ air concentrations of 

sulfuric acid were below the MDC of 0.04 mg/m3. During our 

February 2008 visit, sulfuric acid concentrations were between the 

MDC of 0.044 mg/m3 and the MQC of 0.14 mg/m3. All employee 

exposures measured during both site visits were well below the 

NIOSH REL and OSHA PEL for sulfuric acid of 1 mg/m3, TWA 

over an 8- to10-hour workday.

During our February and October 2008 visits, we collected PBZ 

air samples for manganese, cobalt, and nickel on employees who 

worked either 8-hour or 12-hour, day or night, work shifts. The fullshift PBZ air concentrations for cobalt ranged from 

ND–0.0086 mg/m3 and were below the applicable OELs. Nickel 

concentrations ranged from ND–0.0036 mg/m3 and were also 

below applicable OELs.

The manganese PBZ air sampling results are summarized by job 

title in Table 1. The highest PBZ concentrations measured were 

among digest CCOs, product preparation operators, mechanics, 

and ore trammers. Out of the 63 PBZ air samples for manganese, 

2 exceeded the NIOSH REL of 1 mg/m3, and 16 exceeded the 

ACGIH TLV of 0.2 mg/m3. Of the 33 PBZ samples collected from 

employees (CCOs and product preparation operators) working 

12-hour shifts, seven exceeded the ACGIH TLV of 0.2 mg/m3. 

However, if the ACGIH TLV for manganese is adjusted (using the 

Brief and Scala model, [Appendix B]) to account for the 12-hour 

work shift, 16 employees would have exceeded the adjusted TLV of 

0.1 mg/m3 for a 12-hour TWA. Additionally, the two full-shift GA 

air samples collected in the filter building were below applicable 

OELs.

Results
Page 8 Health Hazard Evaluation Report 2007-0331-3100

Results (continued)

During the February 2008 and August 2008 site visits, we 

collected task-based (30 to 284 minutes in duration) air samples 

for manganese, cobalt, and nickel. The results showed manganese 

exposure in all tasks: dropping filter mud (0.12 mg/m3), filter 

mud drumming (0.27 mg/m3 and 0.19 mg/m3), spray washing 

filters (0.15 mg/m3), tramming ore chips (0.20 mg/m3), and 

bagging the final product (0.77 mg/m3). The 30-minute task-based 

sample collected when an employee was bagging the final product 

exceeded the ACGIH excursion limit of 0.6 mg/m3 (3 times the 

ACGIH TLV of 0.2 mg/m3 over a 30-minute period) [ACGIH 

2009]. Exposures to cobalt and nickel were below the applicable 

OELs.

Table 1. Summary of full-shift PBZ air sample results for manganese

Date Job Title Location N

Air Concentration, mg/m3

Geometric 

Mean Range # > TLV

February 2008

CCO (12-hour)

Purification 2 0.16 0.052–0.50 1

Product 

Preparation 2 0.35 0.11–1.1 1

Digest 1 0.93* N/A 1

Mechanic All Locations 7 0.22 0.074–1.6 3

Laborer All Locations 1 0.086* N/A 0

August 2008

CCO (12-hour)

Purification 5 0.06 0.015–0.12 0

Product 

Preparation 7 0.066 0.022–0.10 0

Digest 5 0.23 0.18–0.36 3

Cell Room 6 0.043 0.021–0.092 0

Mechanic All Locations 12 0.098 0.035–0.33 3

Laborer All Locations 1 0.36* N/A 1

Electrician All Locations 4 0.043 0.027–0.061 0

Operator (12-hour) Product 

Preparation 4 0.19 0.12–0.40 1

Ore Trammer Ore Room 6 0.12 0.037–0.38 2

NIOSH REL (up to a 10-hour TWA) 1

OSHA ceiling limit 5

ACGIH TLV (8-hour TWA) 0.2†

N/A = not applicable (only one sample collected for this job task).

*Actual PBZ air sampling concentration.

†Adjusted for a 12-hour work shift the ACGIH TLV would be 0.1 mg/m3.
Health Hazard Evaluation Report 2007-0331-3100 Page 9

Results (continued) Employees informed us that when they worked near the filter 

press area or near the furnace in the ore room and when they used 

moistened disposable towelettes (alcohol based) for cleaning safety 

glasses, the Toxi Ultra gas detectors exceeded the alarm set-point 

for hydrogen sulfide. When walking between the purification 

building and cell rooms 3 and 4, we also observed that the 

instruments exceeded the alarm set-point. However, the stationary 

area monitors for hydrogen sulfide installed by Erachem did not 

sound an alarm during our evaluation. The gas detectors’ response 

could be a result of instrument malfunction; therefore, we have not 

reported the PBZ air sampling data for hydrogen sulfide.

Document Review 

Erachem provided two consultants’ reports for our review. On 

August 11, 2006, a noise evaluation was conducted on cell room 

employees. Full-shift dosimetry on three of four employees showed 

that their average noise exposures exceeded the OSHA AL of 

85 dBA, but did not exceed the OSHA PEL of 90 dBA. On 

October 4, 2007, an industrial hygiene evaluation was conducted 

in which eight total dust and six respirable dust PBZ air samples 

were collected over the full shift and analyzed for manganese, 

cobalt, nickel, and cadmium. One total dust PBZ air sample 

collected from a product preparation CCO (0.18 mg/m3) was close 

to the ACGIH TLV of 0.2 mg/m3 for manganese, and another air 

sample collected from a product preparation operator (0.44 

mg/m3) exceeded the ACGIH TLV. These results are similar to the 

air sample results obtained during our February and October 2008 

site visits.

Our review of Erachem’s written respiratory protection programs 

revealed inconsistencies. The program requires a loose-fitting 

hood PAPR equipped with a HEPA filter when replacing dust 

collector filters and during sand blasting operations. However, 

during our August 2008 site visit, an employee who had replaced 

dust collector filters wore an air-purifying elastomeric half-mask 

respirator equipped with P100 filters, not the required PAPR. 

Management representatives informed us that employees are 

required to wear an air-purifying elastomeric half or full facepiece 

respirator equipped with P100 filters when drumming the filter 

mud. Use of the elastomeric half-mask respirator is not addressed 

in the written program.
Page 10 Health Hazard Evaluation Report 2007-0331-3100

Results (continued)

Employee Interviews

A convenience sample of 11 employees from six different job 

categories (CCO, harvester, trammer operator, product preparation 

operator, utility staff, and maintenance staff) was interviewed. 

They had been employed at the company for an average of 14 years 

(range: 1 to 38 years). Five reported no work-associated health 

problems. Four reported having nosebleeds in the cell rooms or 

around manganese dust, which were typically experienced on the 

first day of work after time off. Two reported sinus problems. 

Although the HHE request form listed pulmonary problems, skin 

and eye irritation, nausea, and exhaustion as health concerns, 

these were not mentioned during the medical interviews or in 

conversations with other NIOSH investigators. Some employees 

were concerned about the long-term effects of nickel, cobalt, and 

acid mist and the hot working environment in the cell rooms. The 

HHE requestors reported that two employees had cancer (one 

with cancer of the lymph nodes and one with cancer of the throat) 

and were concerned that these may be related to work exposures. 

Employees working in the cell rooms are required to wear hearing 

protection, and we observed employees wearing ear plugs and/

or ear muffs. However, the written hearing conservation program 

does not specify the types of hearing protection devices available, 

which employees are required to wear hearing protection, and in 

what areas of the facility hearing protection is required.

Our review of the OSHA Logs showed that since 2002, 4 cases of 

chemical and thermal burns and 14 injuries resulting from falls 

and other musculoskeletal injuries such as sprains and strains were 

recorded among cell room employees (Table 2).

Table 2. Summary of incidents among cell room employees reported in OSHA Logs

Year Chemical and

thermal burns

Falls, strains, and

other injuries

2002 1 3

2003 2 2

2004 0 2

2005 1 2

2006 0 2

2007 0 3

Total 4 14
Health Hazard Evaluation Report 2007-0331-3100 Page 11

Results (continued) Although the interviews may not have captured all of the health 

effects reported in the request, these will be addressed in the 

discussion section of this report.

Other observations 

We observed that visibility was limited in cell rooms due to fogging, 

especially during early morning hours and after sunset. In addition 

to limited visibility, when the harvesters walk on top of cell tanks, 

they encounter uneven walking surfaces and other trip hazards that 

could result in falling into empty cell tanks or getting thermal and 

chemical burns from the hot cell feed. In 2007, Erachem started 

keeping two sides of the cell room buildings open in the summer 

to increase natural ventilation and improve visibility. To improve 

visibility during winter at least one side of the cell room is covered, 

and radiant area heaters are placed near the cell tanks’ surface to 

reduce fogging. Although not part of this evaluation, employees 

may be at risk of heat stress and/or strain due to high temperatures 

and humidity in the cell rooms, especially during summer. We 

observed that the control room areas and the production floor 

(especially the ore room) were dusty and that employees used dry 

sweeping methods to clean these areas.

Our air sampling results indicated that Erachem employees’ 

manganese levels may exceed OELs during ore handling and 

transferring, processing the intermediate product, and bagging 

the EMD. Previous evaluations conducted at other EMD 

manufacturing facilities have shown similar results. A previous 

HHE conducted by NIOSH at this same Erachem plant found 

employees overexposed to manganese (0.43–3.2 mg/m3) during 

briquetting and bagging operations [NIOSH 1994]. The briquetting 

operation (production of small manganese/aluminum bricks), has 

been discontinued at Erachem. A large cross-sectional study of 141 

production workers in an EMD production facility indicated that 

employees were exposed to manganese air concentrations of 0.07–

8.61 mg/m3 [Roels et al. 1992].

In our February 2008 visit, the exposures of a product preparation 

CCO and a mechanic working in the maintenance shop exceeded 

the NIOSH REL for manganese. The product preparation CCO, 

in addition to normal daily activities, spent time with a team of 

Discussion
Page 12 Health Hazard Evaluation Report 2007-0331-3100

Discussion (continued) mechanics repairing a broken belt filter in the product preparation 

area where EMD is present in powdered form. This product 

preparation CCO’s air sampling result was much higher than our 

August 2008 air sampling results for the same group, suggesting 

that some maintenance activities may result in overexposure to 

manganese. We also observed that the employees working in the 

product preparation area did not wear respirators while doing 

their regular job duties. The second air sample that exceeded the 

NIOSH REL was collected from a mechanic primarily cutting and 

grinding metal parts in the maintenance shop. The maintenance 

shop had a welding local exhaust ventilation system (Figure 7), 

which can also be used when cutting and grinding metal to help 

reduce employee exposures. Additionally, such local exhaust hoods 

are most efficient in capturing contaminants at distances less than 

1 foot so employees should safely work as close as possible to the 

local exhaust hood.

The August 2008, PBZ air sampling for manganese indicated that 

the product preparation operators and digest CCOs are exposed to 

manganese concentrations that exceed the ACGIH TLV of 

0.2 mg/m3. During their normal workday, product preparation 

operators spend most of their time either tramming EMD chips or 

bagging the final product. Digest CCOs spend their time working 

in their area and in the filter building control room. Because our 

full-shift GA air samples collected in the filter building control 

room were below the OELs, the job tasks that digest CCOs 

undertake outside of the filter building control room primarily 

contribute to their manganese overexposure.

CCOs and product preparation operators work 12-hour work 

shifts; OELs recommended for an 8- to 10-hour work shift may 

not fully protect such employees. OELs modified by the Brief and 

Scala model should be used in such cases, and employee exposures 

should be limited below these modified OELs to help reduce 

cumulative exposure to hazardous chemical agents.

Ore trammers who work with raw ore and are responsible for 

changing the filter cartridge from the dust collector for the ball 

mill crusher had some of the highest manganese exposures. Ore 

trammers also have the potential to be exposed to coal dust when 

tramming coal and doing maintenance work on the dust collector. 

Although not part of this evaluation, coal dust exposure should be 

investigated to ensure employee exposures are not exceeding any 

applicable OELs.

Figure 7. Local exhaust ventilation for 

 welding in maintenance shop.
Health Hazard Evaluation Report 2007-0331-3100 Page 13

Discussion (continued) Because Erachem employee job tasks vary daily it is difficult to 

pinpoint the particular task(s) from which manganese exposures 

arise. Our task-based air sampling did identify employee job tasks 

that resulted in elevated manganese concentrations such as bagging 

the EMD product, filter mud drumming, and ore tramming. 

Although short-term sample concentrations are not directly 

comparable to full-shift OELs, our results and future Erachem 

evaluations of employee exposures during specific job tasks will 

provide insight into how each task contributes to employees’ 

overall manganese exposures. This information could help guide 

efforts in implementing engineering and/or administrative 

controls and designing an effective exposure assessment strategy. 

Until controls are implemented, employees should use respiratory 

protection when conducting job tasks with the potential for dust 

generation and when handling powdered ore or EMD.

Employees reported nosebleeds when working in the cell rooms 

that contain sulfuric acid. Sulfuric acid mist can cause eye and 

upper respiratory irritation, and acute (short-term) exposure can 

cause nasal irritation that can progress to nosebleeds [Vincoli 

1997]. However, nosebleeds are a common symptom in the general 

population, and can occur when nasal mucous membranes dry 

out under dry weather conditions [Gifford and Orlandi 2008]. 

The symptoms of upper respiratory irritation can also be caused 

by exposure to dust, and dry weather can contribute to dust 

generation. Our air sampling in 2007 and 2008 indicated that 

sulfuric acid concentrations were well below the applicable OELs, 

so we cannot attribute the nosebleeds to sulfuric acid exposure.

Interviewed employees at Erachem were concerned about cancer 

resulting from work exposures. Employees reported two cases of 

cancer, one of the lymph nodes and another of the throat. We 

were not able to obtain more detailed information about these 

two cases, such as work and exposure history and medical records 

with biopsy results. The potential for workplace exposure to cancercausing agents exists. IARC classifies cobalt with tungsten carbide 

as group 2A, probably carcinogenic to humans, and cobalt without 

tungsten carbide as group 2B, possibly carcinogenic to humans 

[IARC 2006]. Also, IARC classifies nickel compounds as group 1, 

carcinogenic to humans and metallic nickel as 2B [IARC 1997]. 

Exposure to nickel has been associated with cancer of the lung 

and nasal sinuses. Occupational exposure to strong inorganic-acid 

mists containing sulfuric acid is classified as group 1, and has been 

associated with throat cancer [IARC 1992]. Although we are unable 
Page 14 Health Hazard Evaluation Report 2007-0331-3100

Discussion (continued) to determine whether individual cancers may be due to specific 

exposures that may have occurred 15 to 20 years ago, this type of 

throat cancer is consistent with occupational exposures [Steenland 

et al. 1988]. We would also have to consider exposures unrelated to 

work such as tobacco and excessive use of alcohol. Although it may 

not be representative of past exposures, our air sampling indicated 

that the employees’ exposures to nickel, cobalt, and sulfuric acid 

were below all applicable OELs, so that the current risk of cancer 

would be low.

Review of the noise evaluation report provided by management 

indicates that noise levels in cell rooms were below the OSHA 

PEL of 90 dBA, but above the OSHA AL of 85 dBA; therefore, 

employees may be at risk of hearing loss. NIOSH recommends 

a noise exposure limit of 85 dBA as an 8-hour TWA [NIOSH 

1998]. The NIOSH REL for noise exposure is adjusted to 83.2 

dBA for 12-hour work shifts, and the OSHA AL is adjusted to 

82.1 dBA for 12-hour shifts. Although Erachem has a hearing 

conservation program based upon the OSHA AL, NIOSH 

recommends that companies implement a hearing loss prevention 

program when noise exposures exceed the REL. We observed that 

harvesters working in the cell rooms were wearing either ear plugs 

or ear muffs for hearing protection. Employees’ use of hearing 

protection devices should be monitored and continued in cell 

rooms to prevent noise-induced hearing loss. The written hearing 

conservation program should be updated to identify locations and 

the type of hearing protection required in the plant.

We observed employees wearing respirators that did not comply 

with the written respiratory protection program. The written 

program did not identify job tasks where respiratory protection is 

required. These observations reflect inconsistencies between the 

written respiratory protection program and actual respirator use 

among Erachem employees.

Employees had concerns about a multitude of issues related to 

safety and environmental exposures while working in the cell 

rooms. The combination of high cell temperature and reactive 

sulfuric acid can decompose the polypropylene beads, resulting in 

sulfur dioxide and carbon dioxide emissions [Cameron and Main 

1983]. Employee exposures to sulfur dioxide should be evaluated to 

ensure they do not exceed applicable OELs. The work environment 

in cell rooms and unsafe work practices such as walking on top 

of cell tanks when harvesting anodes place employees at risk 
Health Hazard Evaluation Report 2007-0331-3100 Page 15

Discussion (continued) of injuries and burns in the cell rooms. Falling into empty cell 

tanks could be fatal, and Erachem management should look 

into alternative methods of harvesting EMD from anodes that 

would not require employees to walk on top of uncovered cell 

tanks. Tennessee OSHA conducted an inspection on April 16, 

2008, upon receipt of an employee complaint about similar 

safety concerns in the cell rooms. Tennessee OSHA is working 

with Erachem to resolve the risk of falling into empty cell tanks. 

Erachem management should also improve visibility in the cell 

rooms so that employees can perform their work safely.

We observed that employees used brooms and dust pans when 

cleaning production floors and the control room. Dust can become 

airborne from dry sweeping; therefore, wet cleaning practices or 

vacuum cleaners with HEPA filters should be used to minimize 

entrainment of dust in the air.

Our air sampling results show that all employee job titles except 

cell room CCOs and electricians are exposed to manganese 

air concentrations exceeding the NIOSH REL, ACGIH TLV, 

or ACGIH excursion limit. Employees are not overexposed to 

cobalt, nickel, and sulfuric acid. Although we are unable to assess 

the work-relatedness of individual cases, throat cancer has been 

associated with workplace exposure to sulfuric acid mist. The 

written respiratory protection and hearing conservation program 

are deficient, with inconsistencies between the written program 

and current practice. Limited visibility and fall and trip hazards 

were observed in the cell rooms.

We recommend the actions listed below to create a more healthful 

work place. We encourage Erachem to use these recommendations 

to develop an action plan based, if possible, on the hierarchy of 

controls approach (refer to Appendix B: Occupational Exposure 

Limits and Health Effects). This approach groups actions by their 

likely effectiveness in reducing or removing hazards. In most cases, 

the preferred approach is to eliminate hazardous materials or 

processes and install engineering controls to reduce exposure or 

shield employees. Until such controls are in place, or if they are 

not effective or feasible, administrative measures and/or personal 

protective equipment may be needed.

Recommendations

Conclusions
Page 16 Health Hazard Evaluation Report 2007-0331-3100

Recommendations

(continued) 1. Reduce employees’ exposure to manganese dust by the 

following methods:

a. Using engineering controls to reduce dust generation 

such as:

● Installing enclosed hoods for the belt filter in the 

product preparation area.

● Using local exhaust ventilation for the bag filling 

operation. ACGIH recommends that a local exhaust 

hood installed for this operation have a flow rate 

range of 1000–1500 cubic feet per minute and a 

maximum capture velocity 500 feet per minute. 

Please refer to the ACGIH publication Industrial 

Ventilation: A Manual of Recommended Practice for 

Design for further guidance on selecting local exhaust 

hoods appropriate to your processes [ACGIH 2007].

b. Providing a minimum of a NIOSH-approved halfmask air purifying respirator with N95 or higher filter 

efficiency for daily wear to employees with job titles 

whose exposure exceeds the OELs until engineering or 

administrative controls can be implemented to reduce 

manganese exposures to below the OELs.

c. Re-evaluating employee exposures after installing 

engineering controls to verify if continued PPE use is 

required. Discontinue PPE use if employee exposures are 

below applicable OELs.

d. Conducting additional air sampling to identify job 

tasks that may be contributing to employees’ overall 

manganese exposure.

e. Improving housekeeping in control room areas and 

throughout the production floor to decrease the amount 

of dust that can become airborne [29 CFR 1910.22 (a)]. 

For example, use vacuum cleaners fitted with HEPA 

filters instead of dry sweeping.

2. Use nonreactive fiber reinforced plastic covers to reduce acid 

mist and steam rising from the cell tanks (see Figure 8). This 

will reduce fogging and improve visibility in the cell rooms.
Health Hazard Evaluation Report 2007-0331-3100 Page 17

Recommendations

(continued)

3. Consult with a firm specializing in safety and fall protection 

to develop solutions that would not require employees to 

walk on the cell surface. For example, covering empty cell 

tanks or placing barricades along the full length of the cell 

tank may help prevent falls [29 CFR 1910.22 (c)]. Employees 

could also use a crane-mounted fixed/extendable walkway to 

access the cell tanks (Figure 9).

Figure 8. Cell tanks covered with fiber-reinforced plastic covers used at 

 Manganese Ore (India) Limited, India [Engergymanagertraining 

 2006]. 

Figure 9. Illustration depicting the use of extendable walkway in cell rooms. 
Page 18 Health Hazard Evaluation Report 2007-0331-3100

Recommendations

(continued) 4. Use the existing local exhaust hoods in the maintenance 

shop when performing metal cutting and grinding tasks. 

Employees should also ensure that the work piece is placed 

as close as possible (ideally less than a foot) from the local 

exhaust hood to improve its capture efficiency.

5. Evaluate cell room employees’ exposure to sulfur dioxide 

and ore trammers’ exposure to coal dust to ensure that 

exposures are not exceeding applicable OELs. Please refer to 

the NIOSH Pocket Guide to Chemical Hazards for guidance 

on air sampling methods appropriate for these chemicals 

[NIOSH 2005].

6. Revise the written respiratory protection program to 

identify the job tasks, type of respirator, and locations 

where respirator use is required. Respiratory hazards should 

be evaluated for job tasks where respiratory protection 

is currently required to ensure that the respirators worn 

are necessary and appropriate. If respirators are deemed 

necessary, the respirator program must identify the type of 

respirator required for those tasks (for example, replacing 

dust collector filters and filter mud drumming). Job tasks 

where employees voluntarily wear respirators should also be 

noted in the written program. Ensure that the requirements 

listed in the OSHA Respiratory Protection Standard (29 

CFR 1910.134) are established and followed by employees. 

The OSHA Small Entity Compliance Guide provides 

guidance for respiratory protection programs and is available 

at www.osha.gov/Publications/secgrev-current.pdf.

7. Revise the written hearing conservation program to identify 

the locations and type of hearing protection required in 

the plant. Comply with all requirements of the OSHA 

Occupational Noise Exposure Standard [29 CFR 1910.95] 

including:

● Supervisors (cell room CCOs) should be held 

accountable for ensuring the proper use of hearing 

protection in designated hazardous noise areas.

● Refer to the OSHA publication titled Hearing 

Conservation available at www.osha.gov /Publications 

/OSHA3074/osha3074.html, NIOSH document 

Preventing Occupational Hearing Loss: A Practical Guide
Health Hazard Evaluation Report 2007-0331-3100 Page 19

Recommendations

(continued) available at www.cdc.gov/niosh/docs /96-110/, and to 

the NIOSH hearing conservation program evaluation 

checklist available at www.cdc.gov/niosh/topics/noise/

solutions/hearingchecklist.html for more information 

on noise and hearing loss.

8. Evaluate employees’ environmental heat exposure when 

working in the cell rooms during the hottest months. Please 

refer to NIOSH publication Criteria for a Recommended 

Standard: Occupational Exposure to Hot Environments available 

at www.cdc.gov/niosh/86-113.html and the NIOSH topic 

page on heat stress available at www.cdc.gov/niosh/topics/

heatstress/ for additional information on related health 

symptoms and how employers and employees can limit 

environmental heat exposures.

9. Employees should inform their supervisor and the health 

and safety committee representative about their work-related 

health concerns. Management should encourage employees 

with health concerns to seek evaluation and care from a 

physician who is board certified in occupational medicine 

and is familiar with the types of exposures employees 

may have had and their health effects. Occupational 

medicine physicians can be found through a variety of 

sources, including the Association of Occupational and 

Environmental Clinics available at www.aoec.org, and the 

American College of Occupational and Environmental 

Medicine available at www.acoem.org.

ACGIH [2007]. Industrial ventilation: A manual of recommended 

practice for design. 26th ed. Cincinnati, OH: American 

Conference of Governmental Industrial Hygienists, pp.13–15.

ACGIH [2009]. 2009 TLVs® and BEIs®: Threshold limit values 

for chemical substances and physical agents and biological 

exposure indices. Cincinnati, OH: American Conference of 

Governmental Industrial Hygienists.

Cameron GG, Main BR [1983]. The action of concentrated 

sulfuric acid on polyethylene and polypropylene: Part 1-Evolution 

of sulfur dioxide and carbon dioxide. Polymer degradation and 

stability 5(3):215–225.

References
Page 20 Health Hazard Evaluation Report 2007-0331-3100

References (continued) CFR. Code of Federal Regulations. Washington, DC: U.S. 

Government Printing Office, Office of the Federal Register.

Engergymanagetraining [2006]. Manganese ore (India) 

Limited. [http://docs.google.com/viewer?a=v&q=cach

e%3AXm03SZPscpgJ%3Awww.energymanagertraining.

com%2Feca2006%2FAward2006_CD%2F20Mining%2FMan

ganeseOreLimitedDongriBuzurgMine.pdf+ManganeseOreLim

itedDongriBuzurgMine&hl=en&gl=us&sig=AHIEtbQtHeqHZFcEQ6Vov5S_-kX9M9ZtA&pli=1]. Date accessed: December 

2009.

Gifford TO, Orlandi RR [2008]. Epistaxis. Otolaryngol Clin North 

Am 41(3):525–536.

IARC [1992]. IARC monographs on the evaluation of the 

carcinogenic risk of chemicals to man: Occupational exposures to 

mists and vapors from strong inorganic acids; and other industrial 

chemicals. Vol. 54. Lyon, France: World Health Organization, 

International Agency for Research on Cancer. pp. 41-130. [http://

monographs.iarc.fr/ENG/Monographs/vol54/index.php]. Date 

accessed: December 2009.

IARC [1997]. IARC monographs on the evaluation of the 

carcinogenic risk of chemicals to man: Chromium, nickel and 

welding. Summary of data reported and evaluation. Vol. 49. Lyon, 

France: World Health Organization, International Agency for 

Research on Cancer. pp. 8–9. [http://monographs.iarc.fr/ENG/

Monographs/vol49/volume49.pdf]. Date accessed: December 

2009.

IARC [2006]. IARC monographs on the evaluation of the 

carcinogenic risk of chemicals to man: Cobalt in hard metals and 

cobalt sulfate, gallium arsenide, indium phosphide and vanadium 

pentoxide. Vol. 86. Lyon, France: World Health Organization, 

International Agency for Research on Cancer. pp. 132–133. 

[http://monographs.iarc.fr/ENG/Monographs/vol86/mono86-6.

pdf]. Date accessed: December 2009.

NIOSH [1994]. Hazard evaluation and technical assistance report: 

Chemetals Incorporated, New Johnsonville, TN. By Decker JA, 

Kiefer M, Hanley K. Cincinnati, OH: U.S. Department of Health 

and Human Services, Centers for Disease Control and Prevention, 

National Institute for Occupational Safety and Health, NIOSH 

HETA Report No. 94-0213-2469.
Health Hazard Evaluation Report 2007-0331-3100 Page 21

References (continued) NIOSH [1998]. Criteria for a recommended standard: 

occupational noise exposure (revised criteria 1998). Cincinnati, 

OH: U.S. Department of Health and Human Services, Centers 

for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, DHHS (NIOSH) Publication No. 

98-126.

NIOSH [2005]. NIOSH pocket guide to chemical hazards. 

Cincinnati, OH: U.S. Department of Health and Human Services, 

Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, DHHS (NIOSH) Publication No. 

2005-149. [www.cdc.gov/niosh/npg/]. Date accessed: December 

2009.

Roels HA, Ghyselen P, Buchet JP, Ceulemans E, Lauwerys RR 

[1992]. Assessment of the permissible exposure level to manganese 

in workers exposed to manganese dioxide dust. Br J 

Ind Med 49(1):25–34.

Steenland K, Schnorr T, Beaumont J, Halperin W, Bloom T 

[1988]. Incidence of laryngeal cancer and exposure to acid mists. Br 

J Ind Med 45(11):766–776.

Vincoli JW [1997]. Risk management for hazardous chemicals. 

Boca Raton, FL: CRC Press.
Page 22 Health Hazard Evaluation Report 2007-0331-3100

Sulfuric acid 

Air samples were collected on silica gel sorbent tubes (400/200 mg) using SKC Pocket Pumps® (SKC 

Incorporated, Eighty Four, Pennsylvania) calibrated at a flow rate of 200 cubic centimeters per minute. 

The inlet port of the sampling pump was connected to the sampling media with Tygon® tubing. All air 

sampling pumps were calibrated before and after use. For PBZ samples, the sampling media were attached 

to the employee’s lapel within the breathing zone, roughly defined as an area in front of the shoulders with 

a radius of 6 to 9 inches. All samples were analyzed for sulfuric acid by ion chromatography according to 

NIOSH Method 7903 [NIOSH 2009].

Manganese, Cobalt, and Nickel 

Air samples were collected on 37-millimeter diameter, 0.8-micrometer pore size mixed cellulose ester 

filters using SKC Air Check® 2000 air sampling pumps (SKC Incorporated, Eighty Four, Pennsylvania) 

calibrated at a flow rate of 2 liters per minute. All air sampling pumps were calibrated before and after use. 

All samples were analyzed for metals by inductively coupled argon plasma–atomic emission spectroscopy 

according to NIOSH Method 7303 [NIOSH 2009].

Reference 

NIOSH [2009]. NIOSH manual of analytical methods (NMAM®), 4th ed. Schlecht PC, O’Connor PF, 

eds. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control 

and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication 

94–113 (August, 1994); 1st Supplement Publication 96–135, 2nd Supplement Publication 98–119; 3rd 

Supplement 2003–154. [www.cdc.gov/niosh/docs/2003-154/]. Date accessed: December 2009.

Appendix A: Methods
Health Hazard Evaluation Report 2007-0331-3100 Page 23

In evaluating the hazards posed by workplace exposures, NIOSH investigators use both mandatory (legally 

enforceable) and recommended OELs for chemical, physical, and biological agents as a guide for making 

recommendations. OELs have been developed by Federal agencies and safety and health organizations to 

prevent the occurrence of adverse health effects from workplace exposures. Generally, OELs suggest levels 

of exposure to which most employees may be exposed up to 10 hours per day, 40 hours per week for a 

working lifetime without experiencing adverse health effects. However, not all employees will be protected 

from adverse health effects even if their exposures are maintained below these levels. A small percentage 

may experience adverse health effects because of individual susceptibility, a pre-existing medical condition, 

and/or a hypersensitivity (allergy). In addition, some hazardous substances may act in combination with 

other workplace exposures, the general environment, or with medications or personal habits of the 

employee to produce health effects even if the occupational exposures are controlled at the level set by 

the exposure limit. Also, some substances can be absorbed by direct contact with the skin and mucous 

membranes in addition to being inhaled, which contributes to the individual’s overall exposure.

Most OELs are expressed as a TWA exposure. A TWA refers to the average exposure during a normal 8- 

to 10-hour workday. Most OELs are established to protect employees working an 8- to 10-hour work day 

or a 40-hour work week. In cases where employees work an extended shift, OELs can be modified to take 

into account the increased uptake due to longer work exposures and the reduced clearance time from the 

body because of the shorter time away from work and exposure. Hence, when comparing air sampling 

concentrations to OELs in the case of employees who worker longer than 8–10 hours or more than 40 

hours a week, employers should exercise caution. For unusual work schedules, the ACGIH refers to the 

Brief and Scala model to reduce the TLV proportionately for both exposure time and reduced recovery 

time [Brief and Scala 1975, 1986]. The reduction factor applicable for employees working 12-hour work 

shifts for 5 or fewer days in a week can be calculated as follows:

TLV reduction factor = (8 / hours worked per day) x (hours off work / 16)

TLV reduction factor = (8 / 12) x (12 / 16) = 0.5

Therefore, the applicable TLV = 0.2 mg/m3 x 0.5 = 0.1 mg/m3.

ACGIH cautions that adjusted TLVs do not have the benefit of historical use and long-term observation 

[ACGIH 2009].

Some chemical substances and physical agents have recommended STEL or ceiling values where health 

effects are caused by exposures over a short period. Unless otherwise noted, the STEL is a 15-minute 

TWA exposure that should not be exceeded at any time during a workday, and the ceiling limit is an 

exposure that should not be exceeded at any time. Additionally, ACGIH recommends excursion limits for 

substances that do not have a TLV-STEL; employee exposure should not exceed three times the TLV for a 

30-minute period and should never exceed five times the TLV [ACGIH 2009]. OSHA, however, currently 

applies the extended work shift adjustment only to full-shift occupational lead exposures [OSHA 1997].

Appendix B: Occupational Exposure Limits & Health Effects
Page 24 Health Hazard Evaluation Report 2007-0331-3100

Appendix B: Occupational Exposure Limits & Health Effects (continued)

In the United States, OELs have been established by Federal agencies, professional organizations, state 

and local governments, and other entities. Some OELs are legally enforceable limits, while others are 

recommendations. The U.S. Department of Labor OSHA PELs (29 CFR 1910 [general industry]; 29 

CFR 1926 [construction industry]; and 29 CFR 1917 [maritime industry]) are legal limits enforceable in 

workplaces covered under the Occupational Safety and Health Act. NIOSH RELs are recommendations 

based on a critical review of the scientific and technical information available on a given hazard and the 

adequacy of methods to identify and control the hazard. NIOSH RELs can be found in the NIOSH Pocket 

Guide to Chemical Hazards [NIOSH 2005]. NIOSH also recommends different types of risk management 

practices (e.g., engineering controls, safe work practices, employee education/training, personal protective 

equipment, and exposure and medical monitoring) to minimize the risk of exposure and adverse health 

effects from these hazards. Other OELs that are commonly used and cited in the U.S. include the TLVs 

recommended by ACGIH, a professional organization, and the WEELs recommended by the American 

Industrial Hygiene Association, another professional organization. The TLVs and WEELs are developed by 

committee members of these associations from a review of the published, peer-reviewed literature. They are 

not consensus standards. ACGIH TLVs are considered voluntary exposure guidelines for use by industrial 

hygienists and others trained in this discipline “to assist in the control of health hazards” [ACGIH 2009]. 

WEELs have been established for some chemicals “when no other legal or authoritative limits exist” 

[AIHA 2009].

Outside the United States, OELs have been established by various agencies and organizations and include 

both legal and recommended limits. Since 2006, the Berufsgenossenschaftliches Institut für Arbeitsschutz 

(German Institute for Occupational Safety and Health) has maintained a database of international OELs 

from European Union member states, Canada (Québec), Japan, Switzerland, and the United States 

available at www.hvbg.de/e/bia/gestis/limit_values /index.html. The database contains international 

limits for over 1250 hazardous substances and is updated annually.

Employers should understand that not all hazardous chemicals have specific OSHA PELs, and for some 

agents the legally enforceable and recommended limits may not reflect current health-based information. 

However, an employer is still required by OSHA to protect its employees from hazards even in the absence 

of a specific OSHA PEL. OSHA requires an employer to furnish employees a place of employment free 

from recognized hazards that cause or are likely to cause death or serious physical harm [Occupational 

Safety and Health Act of 1970 (Public Law 91–596, sec. 5(a)(1))]. Thus, NIOSH investigators encourage 

employers to make use of other OELs when making risk assessment and risk management decisions to 

best protect the health of their employees. NIOSH investigators also encourage the use of the traditional 

hierarchy of controls approach to eliminate or minimize identified workplace hazards. This includes, in 

order of preference, the use of (1) substitution or elimination of the hazardous agent, (2) engineering 

controls (e.g., local exhaust ventilation, process enclosure, dilution ventilation), (3) administrative controls 

(e.g., limiting time of exposure, employee training, work practice changes, medical surveillance), and (4) 

personal protective equipment (e.g., respiratory protection, gloves, eye protection, hearing protection). 

Control banding, a qualitative risk assessment and risk management tool, is a complementary approach 

to protecting employee health that focuses resources on exposure controls by describing how a risk 

needs to be managed. Information regarding control banding is available at www.cdc.gov/niosh/topics/
Health Hazard Evaluation Report 2007-0331-3100 Page 25

Appendix B: Occupational Exposure Limits & Health Effects (continued)

ctrlbanding/. This approach can be applied in situations where OELs have not been established or can be 

used to supplement the OELs, when available.

Sulfuric Acid 

Sulfuric acid is a dense, colorless liquid that is corrosive and nonflammable. Because the vapor pressure of 

sulfuric acid is low, it exists in the air only as a mist or spray. Sulfuric acid is an irritant of the respiratory 

tract, eyes, and skin. A dose-effect relationship for long-term exposure is difficult to determine because a 

number of factors affect the toxic effect, including the particle size of the mist, presence of particulates, 

synergistic and protective agents, and humidity. The IARC has classified sulfuric acid as group 1, 

carcinogenic to humans [IARC 1992]. Some studies have associated sulfuric acid exposure to development 

of laryngeal cancer [Steenland et al. 1988]. However, other organizations, such as NIOSH, OSHA, and 

ACGIH have not yet designated sulfuric acid as a carcinogen.

The NIOSH REL-TWA and the OSHA PEL-TWA for sulfuric acid is 1 mg/m3 [NIOSH 2005; 29 CFR 

1910.1000 Table Z-1]. The ACGIH TLV-TWA for sulfuric acid (thoracic fraction) is 0.2 mg/m3 [ACGIH 

2009]. The TLV is based on minimization of pulmonary irritation, and a margin of safety is incorporated 

to prevent injury to the skin and teeth.

Manganese

Manganese metal is a silver-gray transition-essential element that forms compounds in seven oxidation 

states. Airborne manganese consists primarily of insoluble oxides in particulate form. The size of the 

particulates determines the location and amount of deposition in the pulmonary tract. Larger particles 

(greater than 2.5 μm diameter) generally deposit in the upper airways and are expelled by coughing or 

sneezing or are cleared to the gastrointestinal tract by mucociliary transport. Smaller particles (0.5 to 

2.5 μm diameter) deposit in the pulmonary or alveolar region of the lung, where they are cleared to 

the gastrointestinal tract or absorbed [ATSDR 2008]. The amount of manganese absorbed from the 

gastrointestinal tract is approximately 3%, but considerable variability has been reported depending 

on the manganese compound, age, and iron deficiency. Manganese deposited in the deep pulmonary 

region of the lung not transferred to the gastrointestinal tract is likely absorbed into the blood stream. 

Continual overexposure to manganese results in chronic manganese intoxication. The manifestations of 

overexposure are neurologic in nature and begin insidiously with headache, body weakness, irritability, 

and sometimes psychosis. Severe sleepiness, followed by insomnia, often is found early in the disease. As 

exposure continues, symptoms such as tremor, speech impairment, numbness, and incoordination may 

occur. A characteristic sign of chronic manganese intoxication is the complete absence of facial expression. 

Although manganese intoxication resembles Parkinsonism, they can be distinguished clinically and by 

pathology.
Page 26 Health Hazard Evaluation Report 2007-0331-3100

Appendix B: Occupational Exposure Limits & Health Effects (continued)

Research on subclinical health effects in workers exposed to manganese below OELs has shown limited 

and conflicting evidence of neurotoxicity. Comparing results among studies is difficult because of 

differences in neurobehavioral tests used, study types and demographics, exposure measurements, and 

statistical analyses. For example, a study of EMD workers exposed to manganese air concentrations of 

0.07–8.61 mg/m3 showed that they performed neurofunctional tests (visual reaction time, eye-hand 

coordination, and hand steadiness) less satisfactorily than the unexposed group [Roels et al. 1992]. 

Another study found memory and attention deficits only in men with blood manganese levels above the 

median of 7.5 micrograms per liter [Mergler et al. 1999]. In one review, only motor skills and reaction 

speed were consistently impaired in the exposed groups [Health Canada 2008]. Some researchers 

recommend a battery of neurobehavioral tests to document possible subclinical effects of chronic, lowlevel manganese exposure [Zoni et al. 2007]. Neurobehavioral tests need to be conducted by experienced 

technicians in a controlled setting, and the interpretation of abnormalities has to take into account other 

possible causes, such as exposures outside of work, liver disease, and true Parkinsonism. The interpretation 

of abnormal neurobehavioral tests in the setting of workplace exposure to low levels of manganese is 

difficult, and abnormalities found in asymptomatic workers do not necessarily imply progression to disease 

[Santamaria et al. 2007].

Blood manganese levels can be measured, but have shown poor reliability in tracking low-level exposure 

to inhaled manganese [Smith et al. 2007]. Manganese levels in hair are variable depending on hair color 

and use of dyes, and should not be used to follow exposure. Magnetic resonance imaging has been used 

to show manganese accumulation in areas of the brain [Health Canada 2008] but following exposure over 

time is impractical.

The NIOSH REL-TWA for manganese and its compounds is 1 mg/m3, and the NIOSH STEL is 3 mg/m3

[NIOSH 2005]. OSHA does not have a PEL for manganese for full-shift exposures but does have a ceiling 

limit of 5 mg/m3 which should not be exceeded at any time [29 CFR 1910.1000 Table Z-1]. The ACGIH 

TLV-TWA is 0.2 mg/m3 [ACGIH 2009].

Cobalt 

Cobalt is a grey, malleable metal, present as an element in ores. It is an essential trace element for humans, 

formed in various salts, and used in vitamin B12 manufacture, nuclear medicine, semiconductors, and in 

steel alloys. Exposure to elevated levels of cobalt can cause cancer and gastrointestinal irritation, nausea, 

and vomiting. Inhaled cobalt can lead to severe pulmonary damage (e.g., pulmonary edema, pulmonary 

fibrosis, and pneumoconiosis). Skin exposure can cause irritant and allergic contact dermatitis [Vincoli 

1997].

The NIOSH REL-TWA for cobalt is 0.05 mg/m3, while the OSHA PEL-TWA is 0.1 mg/m3 [NIOSH 

2005; 29 CFR 1910.1000 Table Z-1]. The ACGIH TLV-TWA for inorganic cobalt compounds is 0.02 

mg/m3 [ACGIH 2009].
Health Hazard Evaluation Report 2007-0331-3100 Page 27

Appendix B: Occupational Exposure Limits & Health Effects (continued)

Nickel 

Nickel is a hard, silvery-white metal used in alloys, electroplating, electroformed coatings, alkaline storage 

batteries, and fuel cell electrodes. Exposure to inorganic nickel by ingestion and inhalation can lead to 

poisoning. Inhalation of nickel fumes can cause metal fume fever. Skin contact with nickel can lead to 

irritant and allergic contact dermatitis. Nickel is considered a cancer-causing agent by IARC, leading to 

nasal sinus and lung cancer [IARC 1997; Vincoli 1997].

The NIOSH REL-TWA for nickel, based on its designation as a potential occupational lung carcinogen, is 

0.015 mg/m3 [NIOSH 2005]. The OSHA PEL-TWA for all forms of nickel is 1 mg/m3 [29 CFR 1910.1000 

Table Z-1]. The ACGIH TLV-TWA for insoluble compounds (i.e., nickel sulfide and nickel oxide) of nickel 

is 0.2 mg/m3, for soluble nickel compounds and nickel subsulfide is 0.1 mg/m3, and for elemental nickel 

is 1.5 mg/m3 [ACGIH 2009]. All the TLVs for nickel are applicable to the inhalable fraction of employee 

exposures to particulates.

References 

ACGIH [2009]. 2009 TLVs® and BEIs®: threshold limit values for chemical substances and physical 

agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental 

Industrial Hygienists.

AIHA [2009]. AIHA 2009 Emergency response planning guidelines (ERPG) & workplace environmental 

exposure levels (WEEL) handbook. Fairfax, VA: American Industrial Hygiene Association.

ATSDR [2008]. Toxicological profile for manganese. Draft for public comment (update). Atlanta, GA: 

U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry.

Brief RS, Scala RA [1975]. Occupational exposure limits for novel work schedules. Am Ind Hyg Assoc J 

36(6):467–469.

Brief RS, Scala RA [1986]. Occupational health aspects of unusual work schedules: a review of Exxon’s 

experiences. Am Ind Hyg Assoc J 47(4):199–202.

CFR. Code of Federal Regulations. Washington, DC: U.S. Government Printing Office, Office of the 

Federal Register.

Health Canada [2008] Human health risk assessment for inhaled manganese draft. Ottawa, Ontario. Air 

Health Effects Division, Water, Air and Climate Change Bureau, Health Canada [www.hc-sc.gc.ca/ewhsemt/alt_formats/hecs-sesc/pdf/air/out-ext/_consult/draft_ebauche /manganese-eng.pdf]. Date accessed: 

December 2009.
Page 28 Health Hazard Evaluation Report 2007-0331-3100

Appendix B: Occupational Exposure Limits & Health Effects (continued)

IARC [1992]. IARC monographs on the evaluation of the carcinogenic risk of chemicals to man: 

Occupational exposures to mists and vapors from strong inorganic acids; and other industrial chemicals. 

Vol. 54. Lyon, France: World Health Organization, International Agency for Research on Cancer. pp. 41–

130. [http://monographs.iarc.fr/ENG/Monographs/vol54/index.php]. Date accessed: December 2009.

IARC [1997]. IARC monographs on the evaluation of the carcinogenic risk of chemicals to man: 

Chromium, nickel and welding. Summary of data reported and evaluation. Vol. 49. Lyon, France: World 

Health Organization, International Agency for Research on Cancer. pp. 8–9. [http://monographs.iarc.fr/

ENG/Monographs/vol49/volume49.pdf]. Date accessed: December 2009.

Mergler D, Baldwin M, Belanger S, Larribe F, Beuter A, Bowler R, Panisset M, Edwards R, de Geoffroy 

A, Sassine MP, Hudnell K [1999]. Manganese neurotoxicity, a continuum of dysfunction: results from a 

community based study. Neurotoxicology 20(2-3):327–342.

NIOSH [2005]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health 

and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational 

Safety and Health, DHHS (NIOSH) Publication No. 2005-149. [www.cdc.gov/niosh/npg/]. Date accessed: 

December 2009.

OSHA [1997]. Standard interpretation: calculation methods used under the air contaminants 

standard for extended workshifts. [www.osha.gov/pls/oshaweb/owadisp.show_document ?p_

table=INTERPRETATIONS&p_id=22333]. Date accessed: December 2009.

Roels HA, Ghyselen P, Buchet JP, Ceulemans E, Lauwerys RR [1992]. Assessment of the permissible 

exposure level to manganese in workers exposed to manganese dioxide dust. Br J Ind Med 49(1):25–34.

Santamaria AB, Cushing CA, Antonini JM, Finley BL, Mowat FS [2007]. State-of-the-science review: Does 

manganese exposure during welding pose a neurological risk? J Toxicol Env Health. Part B. 10:417–465.

Smith D, Gwiazda R, Bowler R, Roels H, Park R, Taicher C, Lucchini R [2007]. Biomarkers of Mn 

exposure in humans. Am J Ind Med 50:801–811.

Steenland K, Schnorr T, Beaumont J, Halperin W, Bloom T [1988]. Incidence of laryngeal cancer and 

exposure to acid mists. Br J Ind Med 45(11):766–776.

Vincoli JW [1997]. Risk management for hazardous chemicals. Boca Raton, FL: CRC Press.

Zoni S, Albini E, Lucchini R [2007]. Neuropsychological testing for the assessment of manganese 

neurotoxicity: a review and a proposal. Am J Ind Med 50:812–830.
Health Hazard Evaluation Report 2007-0331-3100 Page 29

Appendix C: Tables

Table C1. Air sample results for sulfuric acid – full-shift (October 25, 2007)

Job Title Assigned Job 

 Location

Sampling Time Air Concentration

(minutes) (mg/m3)

Harvester Cell 4 363 ND

Harvester Cell 4 189* ND

Harvester Cell 3 360 ND

CCO Cell rooms 351 ND

NIOSH REL 1

OSHA PEL 1

MDC 0.040

ND = Not detected, the concentration is below the MDC.

MDC = Minimum detectable concentration calculated by dividing the method limit of detection by the average 

sample volume collected (0.050 cubic meter of air).

* = Pump failure, last noted sampling time

Table C2. Air sample results for sulfuric acid – full-shift (February 20–22, 2008)

Date Job Title Assigned Job 

 Location

Sampling Time Air Concentration

(minutes) (mg/m3)

2/20/2008

Harvester Cell 1 444 Trace

Harvester Cell 1 443 Trace

2/21/2008

Harvester Cell 1 442 Trace

Harvester Cell 1 & 4 457 Trace

Harvester Cell 1 & 4 439 Trace

Harvester Cell 2 679 Trace

Harvester Cell 2 694 Trace

Harvester Cell 3 & 4 434 Trace

CCO Cell rooms 687 Trace

2/22/2008

Harvester Cell 2 460 Trace

Harvester Cell 2 455 Trace

Harvester Cell 3 & 4 448 Trace

Harvester Cell 3 & 4 412 Trace

Harvester Cell 4 450 Trace

Harvester Cell 4 404 Trace

CCO Cell rooms 687 Trace

NIOSH REL 1

OSHA PEL 1

MDC 0.044

MQC 0.14

Trace = Sample result was between the MDC and MQC.

MDC = Minimum detectable concentration calculated by dividing the method limit of detection by the average 

sample volume collected (0.090 cubic meter of air).

MQC = Minimum quantifiable concentration calculated by dividing the method limit of quantitation by the 

average sample volume collected (0.090 cubic meter of air).
Page 30 Health Hazard Evaluation Report 2007-0331-3100

Appendix C: Tables (continued)

Table C3. Air sample results for metals – full-shift (February 21–22, 2008)

Date Job Title Assigned Job

 Location

Sampling 

Time Air Concentration (mg/m3

)

(minutes) Manganese Cobalt Nickel

2/21/2008

CCO (12-hour)

Purification 635 0.052 0.0013 Trace

Product 

preparation 693 0.11 0.00069 Trace

Mechanic All locations 233* 1.6 0.00013 ND

Mechanic All locations 437 0.11 0.00047 0.0010

Mechanic All locations 437 0.074 0.00038 Trace

Mechanic All locations 434 0.15 0.00077 0.014

2/22/2008

CCO (12-hour)

Product 

preparation 665 1.1 Trace ND

Purification 656 0.50 0.0020 0.00091

Digest 539 0.93 0.0031 0.0013

Mechanic All locations 439 0.28 0.00023 Trace

Mechanic All locations 656 0.11 0.00030 Trace

Mechanic All locations 291 0.43 0.00031 Trace

Laborer All locations 332 0.086 0.0035 0.0015

NIOSH REL 1† 0.05 0.015¶ 

OSHA PEL 5‡ 0.1 1

ACGIH TLV 0.2§ 0.02 0.2** 

MDC 0.00029 0.000029 0.00014

MQC 0.0008 0.0001 0.00066

ND = Not detected; the concentration is below the MDC.

Trace = Sample result was between the MDC and MQC.

MDC = Minimum detectable concentration calculated by dividing the method limit of detection by the average 

sample volume collected (0.7 cubic meter of air).

MQC = Minimum quantifiable concentration calculated by dividing the method limit of quantitation by the 

average sample volume collected (0.7 cubic meter of air).

*Pump failure, last noted sampling time

†NIOSH also has a recommended short term exposure limit for manganese of 3 mg/m3.

‡OSHA ceiling limit never to be exceeded during a full shift

§Adjusted for a 12-hour work shift, the ACGIH TLV would be 0.1 mg/m3.

¶Considered a carcinogen by NIOSH

**Inhalable fraction
Health Hazard Evaluation Report 2007-0331-3100 Page 31

Appendix C: Tables (continued)

Table C4. Air sample results for metals – task-based (February 21–22, 2008)

Date Job Title Assigned Job 

Location Job Task

Sampling 

Time Air Concentration (mg/m3

)

(minutes) Manganese Cobalt Nickel

2/21/2008

CCO Purification

Spray 

washing 

filters

284 0.15 0.021 0.0092

CCO Product 

preparation

Catching 

filter mud in 

basement

159 0.12 0.0024 0.00094

2/22/2008

Laborer Filter building 

basement

Drumming 

filter mud 118 0.27 0.021 0.0084

Laborer Filter building 

basement

Drumming 

filter mud 122 0.19 0.011 0.0045

NIOSH REL 1* 0.05 0.015§

OSHA PEL 5† 0.1 1

ACGIH TLV 0.2‡ 0.02 0.2¶

∗NIOSH also has a recommended short term exposure limit for manganese of 3 mg/m3.

†OSHA ceiling limit never to be exceeded during a full shift

‡ACGIH excursion limit for manganese over a 30-minute period is 0.6 mg/m3.

§Considered a carcinogen by NIOSH

¶Inhalable fraction
Page 32 Health Hazard Evaluation Report 2007-0331-3100

Appendix C: Tables (continued)

Table C5. Air sample results for metals – full-shift (August 25–28, 2008)

Date Shift Job Title Assigned Job 

 Location

Sampling 

Time Air Concentration (mg/m3

)

(minutes) Manganese Cobalt Nickel

PBZ Air Samples

8/25/2008

AM

CCO (12-hour)

Cell rooms 652 0.092 0.00029 ND

Digest 664 0.26 0.0011 Trace

Product preparation 684 0.051 0.000052 ND

Purification 636 0.12 0.00063 Trace

Electrician All locations 409 0.061 0.00018 ND

Electrician All locations 424 0.054 0.00011 ND

Laborer All locations 413 0.36 0.0086 0.0036

Mechanic All locations 437 0.066 0.00042 0.0030

Mechanic All locations 435 0.12 0.000097 ND

Mechanic All locations* 438 0.27 0.00010 ND

Operator (12-

hour) Product preparation 689 0.12 Trace ND

Ore trammer Ore room 433 0.26 0.00078 ND

PM

CCO (12-hour)

Cell rooms 668 0.082 0.00018 ND

Digest 709 0.21 0.00084 Trace

Product preparation* 681 0.072 Trace ND

Purification 705 0.015 0.00021 ND

Operator (12-

hour) Product preparation 635 0.19 0.000088 ND

8/26/2008

AM

CCO (12-hour)

Cell rooms 591 0.041 0.000068 ND

Digest 647 0.18 0.00076 Trace

Product preparation 670 0.090 Trace ND

Purification 636 0.042 0.00049 ND

Mechanic All locations 339 0.072 0.00017 ND

Mechanic All locations 348 0.091 0.00015 ND

Mechanic All locations 300 0.049 0.00032 Trace

Operator (12-

hour) Product preparation 673 0.40 0.00034 Trace

Ore trammer Ore room 419 0.38 0.0011 0.00033

PM

CCO (12-hour)

Cell rooms 702 0.034 Trace ND

Digest 503 0.18 0.00064 ND

Product preparation* 713 0.10 Trace ND

Purification 731 0.053 0.00039 ND

Ore trammer Ore room 448 0.037 0.000091 ND
Health Hazard Evaluation Report 2007-0331-3100 Page 33

Appendix C: Tables (continued)

Table C5 (continued). Air sample results for metals – full-shift (August 25–28, 2008)

Date Shift Job Title Assigned Job 

 Location

Sampling 

Time Air Concentration (mg/m3

)

(minutes) Manganese Cobalt Nickel

PBZ Air Samples

 8/27/2008

AM

CCO (12-hour) Product 

preparation 456 0.069 ND ND

Mechanic All locations 444 0.076 0.00098 Trace

Mechanic All locations 453 0.035 0.00025 ND

Operator (12-hour) Product 

preparation* 692 0.14 0.00034 ND

Ore trammer Ore room 479 0.17 0.00051 ND

PM

CCO (12-hour)

Cell rooms 720 0.021 Trace ND

Digest† 734 0.36 0.0024 0.00080

Product 

preparation 730 0.10 Trace ND

Purification 730 0.069 0.0039 0.0017

Ore trammer Ore room 452 0.088 0.00024 ND

8/28/2008 AM

CCO (12-hour)

Cell rooms 452 0.029 Trace ND

Product 

preparation 485 0.022 0.00020 ND

Electrician All locations 433 0.038 0.00013 ND

Electrician All locations 444 0.027 0.000099 ND

Mechanic All locations 447 0.058 0.000079 ND

Mechanic All locations 461 0.33 0.00027 Trace

Mechanic All locations 444 0.23 0.00021 ND

Mechanic All locations 437 0.097 0.00015 ND

Ore trammer Ore room 488 0.070 0.00023 ND

GA Air Samples

8/27/2008 AM Filter building 649 0.027 0.00030 ND

8/28/2008 AM Filter building 442 0.022 0.00024 ND

 NIOSH REL 1 0.05 0.015†

 OSHA PEL 5‡ 0.1 1

 ACGIH TLV 0.2§ 0.02 0.2¶

MDC 0.000070 0.000020 0.00020

MQC 0.00022 0.000060 0.00074

ND = Not detected; the concentration is below the MDC.

Trace = Sample result was between the MDC and MQC.

MDC = Minimum detectable concentration calculated by dividing the method limit of detection by the average 

sample volume collected (1.0 cubic meter of air).

MQC = Minimum quantifiable concentration calculated by dividing the method limit of quantitation by the average 

sample volume collected (1.0 cubic meter of air).

*Difference between pre-shift and post-shift air sampling flow rates ranged from 10%–21%.

†Considered a carcinogen by NIOSH

‡OSHA ceiling limit never to be exceeded during a full-shift

§Adjusted for a 12-hour work shift the ACGIH TLV would be 0.1 mg/m3

¶Inhalable fraction
Page 34 Health Hazard Evaluation Report 2007-0331-3100

Appendix C: Tables (continued)

Table C6. Air sample results for metals – task-based (August 25–28, 2008)

Date Job Title Assigned Job 

Location Job Task

Sampling 

Time Air Concentration (mg/m3

)

(minutes) Manganese Cobalt Nickel

8/25/2008 Operator Product 

preparation Bagging 30 0.77 ND ND

Ore 

 trammer Ore room Tramming ore

213 0.20 0.00072 ND

NIOSH REL 1* 0.05 0.015§

OSHA PEL 5† 0.1 1

ACGIH TLV 0.2‡ 0.02 0.2¶

ND = Not detected, the concentration is below the MDC.

Trace = Sample result was between the MDC and MQC.

*NIOSH also has a recommended short term exposure limit for manganese of 3 mg/m3. 

†OSHA ceiling limit never to be exceeded during a full shift

‡ACGIH excursion limit for manganese over a 30-minute period is 0.6 mg/m3

§Considered a carcinogen by NIOSH

¶Inhalable fraction
Health Hazard Evaluation Report 2007-0331-3100 Page 35

Acknowledgments and

Availability of Report

The Hazard Evaluations and Technical Assistance Branch 

(HETAB) of the National Institute for Occupational Safety and 

Health (NIOSH) conducts field investigations of possible health 

hazards in the workplace. These investigations are conducted 

under the authority of Section 20(a)(6) of the Occupational Safety 

and Health Act of 1970, 29 U.S.C. 669(a)(6) which authorizes 

the Secretary of Health and Human Services, following a written 

request from any employer or authorized representative of 

employees, to determine whether any substance normally found 

in the place of employment has potentially toxic effects in such 

concentrations as used or found. HETAB also provides, upon 

request, technical and consultative assistance to federal, state, and 

local agencies; labor; industry; and other groups or individuals to 

control occupational health hazards and to prevent related trauma 

and disease.

The findings and conclusions in this report are those of the 

authors and do not necessarily represent the views of NIOSH. 

Mention of any company or product does not constitute 

endorsement by NIOSH. In addition, citations to websites 

external to NIOSH do no constitute NIOSH endorsement of 

the sponsoring organizations or their programs or products. 

Furthermore, NIOSH is not responsible for the content of these 

websites. All Web addresses referenced in this document were 

accessible as of the publication date.

This report was prepared by Srinivas Durgam and Carlos 

Aristeguieta of HETAB, Division of Surveillance, Hazard 

Evaluations and Field Studies. Industrial hygiene field assistance 

was provided by Chad Dowell, Karl Feldmann, Kenneth Fent, 

Manuel Rodriguez, and Seung-Hee Jang. Analytical support 

was provided by Bureau Veritas North America. Health 

communication assistance was provided by Stefanie Evans. 

Editorial assistance was provided by Ellen Galloway. Desktop 

publishing was performed by Robin Smith.

Copies of this report have been sent to employee and 

management representatives at Erachem Comilog, Inc., the state 

health department, and the Occupational Safety and Health 

Administration Regional Office. This report is not copyrighted and 

may be freely reproduced. The report may be viewed and printed 

at www.cdc.gov/niosh/hhe. Copies may be purchased from the 

National Technical Information Service at 5825 Port Royal Road, 

Springfield, Virginia 22161.
Below is a recommended citation for this report:

NIOSH [2009]. Health hazard evaluation report: evaluation of potential exposures 

at an electrolytic manganese dioxide processing plant, New Johnsonville, TN. 

By Durgam S, Aristeguieta C. Cincinnati, OH: U.S. Department of Health and 

Human Services, Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH HETA No. 2007-0331-3100. 

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