Evaluation of 

Chemical Hazards 

and Noise Exposures 

at a Drum Refurbishing 

Plant – Indiana

Kenneth W. Fent, PhD

Elena Page, MD, MPH

Scott E. Brueck, MS, CIH

Health Hazard Evaluation Report

HETA 2010-0031-3130

June 2011

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 2010-0031-3130 Page i

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

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

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

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

Assessment.....................................................................................................3

Results..............................................................................................................5

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

Conclusions................................................................................................. 14

Recommendations.................................................................................... 14

References.................................................................................................... 18

Contents

Acknowledgments

Appendix A:

Appendix B: 

Methods........................................................................................................ 19

Occupational Exposure Limits and Health Effects......................... 21

Acknowledgments and Availability of Report................................ 27
Page ii Health Hazard Evaluation Report 2010-0031-3130

Abbreviations

ACGIH® American Conference of Governmental Industrial Hygienists

AL Action level

CFR Code of Federal Regulations

dB Decibels

dBA Decibels, A-weighted

HHE Health hazard evaluation

HTL Hearing threshold level

Hz Hertz

MDC Minimum detectable concentration

mg Milligrams

mg/m3 Milligrams per cubic meter

MQC Minimum quantifiable concentration

MSDS Material safety data sheet

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

PBZ Personal breathing zone

PEL Permissible exposure limit

PPE Personal protective equipment

PVC Polyvinyl chloride

REL Recommended exposure limit

SLM Sound level meter

STS Standard threshold shift

STEL Short-term exposure limit

TLV® Threshold limit value

TTS Temporary threshold shift

TWA Time-weighted average

VOC Volatile organic compound

WEELTM Workplace environmental exposure level
Health Hazard Evaluation Report 2010-0031-3130 Page iii

The National Institute for 

Occupational Safety and 

Health (NIOSH) received 

a confidential employee 

request for a health 

hazard evaluation at a 

drum refurbishing plant 

in Indiana. The requestors 

reported respiratory 

irritation, chemical burns, 

and headaches from 

exposure to chemicals 

in the drums. Employees 

were also concerned 

about exposure to noise.

Highlights of the

NIOSH Health

Hazard Evaluation

What NIOSH Did

● We evaluated the plant in February 2010 and again in 

March 2010.

● We observed the work being done at the plant. We also asked 

employees about their work and medical history and if they 

had any symptoms or health concerns related to their work.

● We measured aromatic hydrocarbons and sodium hydroxide 

levels in the air.

● We measured noise exposures.

What NIOSH Found

● Most employees said they had no symptoms related to their 

work. Some employees did, however, report symptoms that 

were consistent with airborne exposure to solvents.

● We measured trimethyl benzene levels above occupational 

exposure limits (OELs) in the tote wash department. All 

other air sampling results were below OELs.

● There was potential for skin exposure to solvents throughout 

the plant.

● All noise exposures were above the NIOSH recommended 

exposure limit and the Occupational Safety and Health 

Administration (OSHA) Action Level of 85 A-weighted 

decibels (dBA).

● Pressure washing of drums and totes resulted in the highest 

noise levels in the plant. Some of these noise exposures 

exceeded 100 dBA.

● The plant had no health and safety committee.

What Managers Can Do

● Replace Aromatic 100 with a less hazardous solvent for 

cleaning the outside of the totes and drums.

● Add local exhaust ventilation where drums and totes are 

emptied and cleaned.

● Install an exhaust hood over drums used to collect residual 

waste emptied from the totes.

● Partially enclose or install a barrier where drums and totes 

are pressure washed. This will help reduce noise levels in 

nearby work areas.
Page iv Health Hazard Evaluation Report 2010-0031-3130

Highlights of the

NIOSH Health

Hazard Evaluation

 (continued)

● Require employees to use both earplugs and earmuffs in areas 

where noise exposures are greater than 100 decibels (dB). 

Earplugs and earmuffs should be provided to employees.

● Follow Indiana OSHA’s recommendation to separate the 

cleaning of drums and totes according to the types of chemicals 

they contain. This separation will help prevent chemical 

reactions that could produce other hazardous chemicals.

● Develop a list of required personal protective equipment 

(PPE) for each job task. This list should be based on a review 

of hazards.

● Retrain employees how to properly wear and maintain the PPE.

● Start a health and safety committee that meets regularly to 

discuss concerns at the plant. This committee should have 

both employee and management representation.

What Employees Can Do

● Wear and maintain all your PPE correctly.

● Wear earplugs and earmuffs in work areas where noise 

exposures are above 100 dB.

● Participate in the health and safety committee.

● Report symptoms related to work to your supervisor or the 

plant safety manager.
Health Hazard Evaluation Report 2010-0031-3130 Page v

NIOSH investigators 

evaluated a drum 

refurbishing plant 

in Indiana because 

of reports of noise, 

respiratory irritation, 

chemical burns, and 

headaches. Although the 

symptoms reported were 

consistent with exposures 

to solvents, most airborne 

exposures to aromatic 

hydrocarbons were 

below OELs. However, 

one employee was 

overexposed to trimethyl 

benzene. Employees 

throughout the plant had 

the potential for dermal 

exposure to solvents 

and other chemicals. All 

personal noise exposure 

measurements exceeded 

NIOSH and OSHA OELs 

for an 8-hour workday.

Summary

In December 2009 NIOSH received a confidential employee 

request for an HHE at a drum refurbishing plant in Indiana. The 

requestors reported respiratory irritation, chemical burns, and 

headaches from exposure to chemicals present in the drums. They 

were also concerned about noise exposure. In response to this 

HHE request, we conducted evaluations on February 2, 2010, and 

March 22–23, 2010.

We interviewed employees during our first visit. We asked them 

about their job history, personal medical history, and if they 

had any symptoms or health concerns related to their work. 

We reviewed the OSHA 300 Logs of Work-related Injuries and 

Illnesses for the years 2006 to 2009 and emergency room records 

for one employee who reported seeking care after exposure to 

chemicals on the job.

During our second visit, we conducted PBZ sampling for VOCs, 

aromatic hydrocarbons, and sodium hydroxide. We measured fullshift TWA personal noise exposures. We measured sound levels 

and conducted one-third octave band frequency analysis from 12.5 

Hz to 20,000 Hz throughout production areas of the plant.

Of the 21 employees we interviewed, only four reported symptoms 

they believed were related to work. Two of these employees 

reported headaches, two reported eye irritation, one reported 

dizziness, and one reported sinus infections. The OSHA Logs 

documented one employee with an STS in an audiogram in 2009, 

one employee with burning eyes in 2007, and four employees with 

chemical burns in 2006. One employee sought emergency room 

care for cough and chest pain after breathing in chemicals at work 

and was treated with a bronchodilator and released with an inhaler 

to use for shortness of breath.

All aromatic hydrocarbon exposures were below applicable OELs 

except one PBZ concentration of trimethyl benzene (150 mg/m3

) 

that exceeded the NIOSH REL and ACGIH TLV of 125 mg/m3

. 

This PBZ sample was from a tote wash department employee who 

wiped the exterior of the totes with Aromatic 100. No sodium 

hydroxide was detected (MDC 0.04 mg/m3

) in any of the samples.

PVC gloves with a cotton lining were provided to the employees 

but are not protective against Aromatic 100. Half-mask N95 

filtering facepiece respirators were available to employees for 

voluntary use. However, we observed employees who were 
Page vi Health Hazard Evaluation Report 2010-0031-3130

Keywords: NAICS 423840 (Industrial Supplies Merchant and 

Wholesalers), drum refurbishing, noise, chemicals, trimethyl benzene

Summary

 (continued) improperly wearing and maintaining these respirators. Some 

employees believed that these respirators protected them against 

vapors and gases; however, these respirators are only effective 

against particles.

All personal noise exposure measurements exceeded the NIOSH 

REL and the OSHA AL of 85 dBA for an 8-hour work shift. Noise 

exposures for employees loading drums, wiping exteriors of drums 

with Dissolve II, pressure washing drums and totes, emptying and 

vacuuming drums, and removing labels from totes all exceeded the 

OSHA PEL of 90 dBA. The drum and tote pressure washers had 

TWA noise exposures above 100 dBA.

We recommended substituting Aromatic 100 with a less hazardous 

solvent for cleaning the outside of the totes and drums and adding 

local exhaust ventilation where drums and totes are being emptied 

and cleaned. Installation of an exhaust hood over drums used to 

collect residual waste emptied from the totes would remove any 

potentially hazardous chemicals that evaporate from the drums. We 

also recommended partially enclosing or installing barrier walls in 

the noisiest areas of the plant to reduce noise levels in the adjacent 

work areas. The company should require dual hearing protection 

(earplugs and earmuffs) for the employees who pressure wash 

drums and totes until TWA noise exposures are reduced to below 

100 dBA. We advised the company to conduct a comprehensive 

hazard assessment to facilitate the selection of PPE as required 

by OSHA [29 CFR 1910.132]. Once this assessment is complete, 

employees need to be retrained on how to properly wear and 

maintain PPE, including hearing protection, gloves, sleeve covers, 

and safety glasses.
Health Hazard Evaluation Report 2010-0031-3130 Page 1

Introduction

In December 2009 NIOSH received a confidential employee 

request for an HHE at a drum refurbishing plant in Indiana. 

The requestors reported respiratory irritation, chemical burns, 

and headaches from exposure to a variety of chemicals present 

in the drums. They were also concerned about noise exposure. 

In response to this HHE request, we conducted evaluations on 

February 2, 2010, and March 22–23, 2010.

The plant had about 50 employees. At the time of our evaluation, 

they were operating one 8-hour shift per day, 3–4 days per week. 

The plant received 55-gallon drums and 275- or 330-gallon 

totes that once held various chemicals. The most common 

types of chemicals stored in the drums were caustics and acids. 

The company accepted only containers that were “Resource 

Conservation and Recovery Act empty,” which they defined as 

drip-dry nonviscous material or up to 1 inch of viscous material. 

The totes were plastic surrounded by a supporting steel mesh; most 

of the drums were plastic. The plant also refurbished steel drums, 

but none were being cleaned during our evaluations. Drums and 

totes were emptied of residual chemicals, cleaned, and then either 

shipped to customers for reuse or recycled.

Drum Refurbishing

After being unloaded outdoors, the drums were sent to the poly 

wash department on a conveyor belt (Figure 1). An employee 

manually removed labels and loaded the drums into a machine 

that flushed the drums with water containing 5% sodium 

hydroxide. Residual chemicals in the drums were emptied into a 

collection tank that fed into the onsite water treatment plant. After 

the drums exited the flush machine, an employee placed the drums 

on a conveyor belt and removed remaining labels with a putty 

knife and Dissolve II (Aztec Corporation, Indianapolis, Indiana). 

Dissolve II is a gel-like substance that contains a petroleum 

hydrocarbon mixture and dipropylene glycol monomethyl ether. 

The conveyor belt then carried the drums to an employee who used 

pressurized water to wash the exterior of the drums. Afterwards, 

another employee scrubbed the drums with a sponge containing 

Dissolve II. From here, the drums entered an automated system 

for further cleaning and then for drying. After the drums exited 

the automated cleaning system, employees visually inspected 

and pressure tested the drums for leaks, then rebung the drums. 

In the final steps, an employee wiped the exterior of the drums 

with a rag containing Aromatic 100 (Univar USA Inc., Kirkland, 
Page 2 Health Hazard Evaluation Report 2010-0031-3130

Introduction

 (continued) Washington) to remove residual markings. Aromatic 100 is a liquid 

that contains petroleum hydrocarbons, trimethyl benzene, xylene, 

and cumene. If needed, an employee touched up the drums with 

latex paint (ACE, Matteson, IL) using a pressurized spray gun 

inside a partially enclosed cross-draft ventilation booth. The paint 

contained 1,2-propylene glycol. The drums were stored nearby until 

they could be loaded onto trucks for shipping to customers.

Tote Refurbishing

After unloading, totes were carried to the tote wash department 

with a forklift and then machine-lifted onto a grated elevated 

platform. Rollers in the floor of the platform allowed employees 

to push the totes to the different stations. Residual chemicals 

in the totes were drained into open head 55-gallon drums 

sitting below the platform. Each week, approximately four of 

these drums were filled with residual chemicals for disposal. 

An employee removed labels from the plaque of the totes using 

a heater gun, putty knife, and occasionally a brush containing 

Dissolve II. Another employee used a sponge containing 

Aromatic 100 to remove adhesive and other markings on 

the totes (Figure 2). The totes were then automatically and 

repeatedly flushed with water to clean the interior. Afterwards, 

an employee used pressurized water to clean the exterior of 

the totes. After drying, the employees visually inspected and 

pressure tested the totes for leaks. Last, the totes were revalved, 

transported using a forklift, and stored or loaded onto trucks 

for shipment to customers.

Drum Recycling

After being unloaded, drums that had exceeded their lifespan or 

had leaks were sent to the regrind department on a conveyor belt. 

To empty the drums of residual chemicals, an employee took the 

drums and turned them upside down over a grated collection tank. 

The collection tank fed into the onsite water treatment plant. The 

employee then used a vacuum to remove other chemicals remaining 

in the drums. Afterwards, the drums were stacked next to the 

grinder. When enough drums were present to run the grinder, the 

drums were lifted on a platform to the second level of the plant. 

Employees then manually fed the drums into the hopper of the 

grinder. The grinder was a machine that shredded the drums into 

small pieces of plastic that were cleaned, collected, and shipped to 

plastic recyclers (Figure 3). The grinder typically ran once or twice 

per week.

Figure 1. Plastic drums entering 

the drum refurbishing plant on a 

conveyor belt.

Figure 2. Employee using sponge 

containing Aromatic 100 to remove 

adhesive from the plaque of the tote.

Figure 3. Grinder used for recycling 

plastic drums.
Health Hazard Evaluation Report 2010-0031-3130 Page 3

Introduction

 (continued) Indiana OSHA conducted an inspection at this plant between 

April 18, 2010, and December 20, 2010, and issued several 

citations. Many of these citations pertained to the mixing of 

incompatible chemicals. According to the Safety Order and

Notification of Penalty from this inspection [IOSHA 2011], acids, 

bases, oxidizers, flammables, combustibles, other highly toxic 

chemicals, and suspected or confirmed carcinogens could mix 

together when dumped from drums into collection tanks or 

from totes into collection drums. The mixing of these chemicals 

could cause violent exothermic reactions or release hazardous 

decomposition products such as carbon monoxide, chlorine, 

ammonia, phosgene, phosphine, hydrogen, hydrogen chloride, 

hydrogen fluoride, hydrogen cyanide, and oxides of nitrogen and 

sulfur. Indiana OSHA recommended that the cleaning of drums 

and totes be segregated according to the type of chemicals they 

contain to prevent the mixing of incompatible chemicals. Other 

citations [IOSHA 2011] included violations of standards related 

to hearing conservation [29 CFR 1910.95], emergency response 

[29 CFR 1910.120], PPE [29 CFR 1910.133], confined spaces [29 

CFR 1910.146], electrical safety [29 CFR 1910.303], and hazard 

communication [29 CFR 1910.1200].

Assessment

We interviewed employees during our first visit. We serially 

selected employees from a roster for interviews that were conducted 

in a private room. We asked the employees about their job history, 

personal medical history, and if they had symptoms or health 

concerns related to job exposures. We reviewed the OSHA 300 Log 

of Work-related Injuries and Illnesses for the years 2006 to 2009. 

We also reviewed emergency room records for one employee who 

reported seeking care after exposure to chemicals on the job.

During our second visit, we conducted PBZ sampling for 

VOCs, aromatic hydrocarbons, and sodium hydroxide. These 

samples were collected from employees who worked in the poly 

wash department, the tote wash department, and the regrind 

department over 2 days. We collected eight VOC samples from 

five employees performing four job tasks. These samples were 

collected for less than 3 hours during the 8-hour work shift. 

Unlike the other samples we collected, the VOC samples were 

qualitative in nature, which means chemicals can be identified 

but not their concentrations. The purpose of these samples was 

to determine the primary volatile constituents in the air.
Page 4 Health Hazard Evaluation Report 2010-0031-3130

Table 1. OELs as TWA concentrations over a work shift (mg/m3)

Cumene Ethylbenzene Naphthalene Toluene Trimethyl

benzene Xylene Benzene

NIOSH REL 245 435 50 375 125 435 0.32

OSHA PEL 245 435 50 750 none 435 3.2

ACGIH TLV 245 435 50 75 125 435 1.6

Assessment

 (continued)

We collected four sodium hydroxide samples from three employees 

performing two job tasks. These samples were collected over short 

time periods (~15 minutes) at processes where caustic wash (5% 

sodium hydroxide) was used to rinse the inside of the drums. 

Because sodium hydroxide was measured over ~15 minutes, STELs 

or ceiling limits are most applicable. The NIOSH REL and ACGIH 

TLV ceiling limit for sodium hydroxide are 2 mg/m3

. OSHA has not 

promulgated a STEL or ceiling limit for sodium hydroxide. More 

information on the sampling methods is provided in Appendix 

A. More information on OELs and potential health effects for the 

chemicals we monitored is provided in Appendix B.

We measured work-shift TWA personal noise exposures of 26 

employees using Larson Davis (Provo, Utah) SparkTM Model 705P 

integrating noise dosimeters. We used a Larson Davis Model 824 

integrating sound level meter and real time frequency analyzer for 

sound level and one-third octave band frequency analysis throughout 

production areas of the facility. Octave band measurements were 

taken at frequencies from 12.5 Hz to 20,000 Hz. Noise monitoring 

methods are further described in Appendix A.

We collected 14 aromatic hydrocarbon samples from nine employees 

performing eight job tasks. These samples were collected over the 

entire work shift (approximately 8 hours). On the basis of results 

of the VOC samples and the compounds listed in the MSDS for 

Dissolve II and Aromatic 100, we analyzed these samples for cumene, 

ethylbenzene, naphthalene, toluene, trimethyl benzene, xylene, 

and benzene. The results were averaged over the sampling period 

and compared to the following work-shift OELs: the NIOSH REL 

[NIOSH 2005], the legally enforceable OSHA PEL [NIOSH 2005], 

and the ACGIH TLV® [ACGIH 2010] (Table 1).
Health Hazard Evaluation Report 2010-0031-3130 Page 5

Results

Employee Interviews

The 21 interviewed employees were from all areas of the plant, 

and all were involved in drum refurbishing. They had worked at 

the plant for an average of 9 years (range: 2–21 years). Seventeen 

reported no work-related symptoms. Two reported headache, two 

reported eye irritation, one reported dizziness when odors were 

especially strong, and one reported sinus infections since beginning 

work at the plant.

The OSHA 300 Logs documented one employee with a significant 

threshold shift in an audiogram in 2009, one employee with 

burning eyes in 2007, and four employees with chemical burns in 

2006. These four employees were involved in a single incident that 

resulted in their burns. After our first visit in February 2010, one 

employee sought care at the emergency room for cough and chest 

pain after breathing in chemicals at work. He was treated with a 

bronchodilator and released with an inhaler to use if he became 

short of breath.

Air Sampling

Several compounds were detected on the VOC screening samples, 

including indene, ethyl acetate, toluene, benzene, naphthalene, 

methyl methacrylate, trimethyl benzene, xylene, and cumene. The 

latter three compounds are listed as components of Aromatic 100, 

which was used in the poly wash and tote wash departments. Many 

of these compounds were measured on the aromatic hydrocarbon 

samples. The PBZ concentrations of cumene, ethyl benzene, 

toluene, trimethyl benzene, and xylene are provided in Table 2. 

The MDCs and MQCs are also provided in Table 2. The MDCs 

and MQCs were calculated by dividing the analytical limits of 

detection and quantitation (mass units) by the minimum volume 

of air sampled. The MDCs and MQCs represent the smallest air 

concentrations that could have been detected (MDC) or quantified 

(MQC) for the volume of air sampled. Concentrations between the 

MDC and MQC are listed in Table 2 but are shown in parentheses 

to point out that there is more uncertainty associated with these 

values than with concentrations above the MQC. All exposures 

were below applicable OELs except one PBZ concentration of 

trimethyl benzene (150 mg/m3

) that was above the NIOSH REL 

and ACGIH TLV of 125 mg/m3

. This concentration was measured 

on March 22, 2010, in the PBZ of an employee in the tote wash 

department who wiped the exterior of the totes with Aromatic 100. 

On the following day, this employee’s exposure was 83 mg/m3

. 
Page 6 Health Hazard Evaluation Report 2010-0031-3130

Indiana OSHA also reported than an employee in the tote wash 

department was overexposed to trimethyl benzene (330 mg/m3

) on 

August 26, 2010 [IOSHA 2011].

The air sampling results for benzene and naphthalene are 

not provided in Table 2 because the concentrations of these 

compounds were near or below their MDCs. The MDC for 

benzene was 0.02 mg/m3

 and the MDC for naphthalene was 0.03 

mg/m3

. These concentrations are well below applicable OELs.

Results

 (continued)

Table 2. Work-shift PBZ concentrations of cumene, ethyl benzene, toluene, trimethyl benzene, and xylene

Dept. Sample 

date

Job task Cumene Ethyl 

benzene

Toluene Trimethyl 

benzenes Xylene 

Poly wash 3/22/2010 Remove labels* 0.043 0.028 (0.14) 13 0.18

Wipe exterior with 

Dissolve II 

0.1 0.053 (0.14) 28 0.31

Wipe exterior with 

Aromatic 100 

0.10 0.018 (0.096) 5.3 0.27

Spray paint 0.14 0.024 0.44 6.2 0.36

3/23/2010 Remove labels 0.039 0.026 ND 10 0.11

Wipe exterior with 

Dissolve II 

0.094 0.022 (0.062) 30 0.14

Rebung 0.035 (0.0024) ND 2.3 0.073

Spray paint 0.080 0.016 1.3 3.8 0.19

Regrind 3/22/2010 Empty and vacuum* 0.031 0.082 (0.072) 5.3 0.46

3/23/2010 Empty and vacuum 0.022 0.019 (0.046) 4.1 0.12

Tote wash 3/22/2010 Remove labels* 0.99 0.032 ND 45 1.8

Wipe exterior with 

Aromatic 100 

3.6 0.1 ND 150 6.6

3/23/2010 Remove labels 0.58 0.016 ND 30 0.99

Wipe exterior with 

Aromatic 100* 

1.8 0.054 ND 83 3.4

MDC 0.003 0.003 0.07 0.01 0.007

MQC 0.015 0.015 0.22 0.044 0.029

*Samples collected over 6.5 hours or less. All other samples were collected over 7.5 hours or more.
Health Hazard Evaluation Report 2010-0031-3130 Page 7

Results

 (continued) The PBZ concentrations of sodium hydroxide were all ND (below 

the MDC of 0.04 mg/m3

). These air samples were collected in 

the PBZs of the employees who loaded and unloaded drums from 

the automatic caustic wash system in the poly wash department. 

Because the MDC is well below the NIOSH REL and ACGIH 

ceiling limit of 2 mg/m3

, we can be certain that these employees 

were not overexposed to sodium hydroxide during this evaluation.

Noise Monitoring

Table 3 summarizes personal noise exposure measurements 

by department and job task. All personal noise exposure 

measurements exceeded the NIOSH REL and the OSHA AL of 

85 dBA for an 8-hour work shift. Additionally, noise exposures 

for employees loading drums, wiping the exterior of drums with 

Dissolve II, spraying drums and totes with pressurized water, 

emptying and vacuuming drums, and removing labels from totes 

exceeded the OSHA PEL of 90 dBA. Of particular note was 

that employees using pressure sprayers in the poly wash and tote 

wash departments had TWA noise exposures above 100 dBA, 

a noise exposure level at which NIOSH recommends the use 

of dual hearing protection (i.e., the combination of earplugs 

and earmuffs). A few employees wore dual protection; however, 

employees using pressure sprayers only wore single protection 

(foam insert earplugs). We noticed that several employees in the 

plant did not properly insert their disposable foam earplugs deep 

enough into the ear canal.

Sound level and one-third octave band noise measurements 

were taken at the pressure washing stations in the tote wash 

and poly wash departments. Overall sound levels for both were 

approximately 104 dB. For the drum pressure washer, high 

frequency noise from approximately 4,000 to 20,000 Hz was 

predominant. The tote pressure washer also had substantial noise 

in frequencies from 10,000 to 20,000 Hz. However, the tote 

pressure washer also had peaks at low frequencies of 80 Hz and 

to a somewhat lesser extent at 160 Hz. Octave band measurement 

results are shown in Figure 4.

Octave band measurements in the audiometric test booth (not 

shown) indicated that noise levels in the booth were below the 

maximum allowable levels specified by OSHA in Table D1 of the 

noise standard [29 CFR 1910.95].
Page 8 Health Hazard Evaluation Report 2010-0031-3130

Results

 (continued)

Table 3. Summary of personal work-shift TWA noise exposure measurements

Department Job task

No. of 

samples

NIOSH REL 

(dBA) OSHA AL (dBA)

OSHA PEL 

(dBA)

Indoor loading Loading drums 4 88.8 – 98.0 86.5 – 96.6 81.3 – 96.3

Poly wash Rebung 2 88.9 – 89.7 88.2 – 89.2 83.3 – 84.8

Poly wash Spray paint 2 87.5 – 89.1 86.5 – 88.2 78.9 – 83.9

Poly wash Wipe exterior with 

Dissolve II

2 94.8 – 96.0 93.7 – 94.5 92.9 – 94.2

Poly wash Remove labels 2 90.9 – 91.3 90.2 – 90.5 87.2 – 88.1

Poly wash

Pressure wash 

drums

2 104.3 – 104.9 102.3 – 102.9 102.0 – 102.7

Regrind Empty and vacuum 

drums

2 92 – 92.6 91.1 – 91.9 89.8 – 90.9

Regrind Operate grinder 3 90.2 – 91.7 88.7 – 90.0 86.0 – 87.6

Regrind Shredder 1 92.3 89.4 86.9

Tote wash Remove labels 1 93.2 92.4 91.4

Tote wash

Pressure wash 

totes

2 98.4 – 102.1 97.1 – 100.3 96.9 – 100.2

Tote wash Revalve 2 90.8 – 92.8 89.9 – 91.5 86.1 – 89.3

Noise Exposure Limits 85.0 85.0 90.0

Other Observations

All employees were required to wear safety glasses, hard hats, and 

steel-toed boots. PVC gloves with a cotton lining were provided to 

employees. Employees reported changing the gloves two times per 

week. An employee in the poly wash department was not wearing 

safety glasses and had cut off his glove cuffs so they no longer 

covered his wrists. This employee said he cut off the glove cuffs 

to make them more comfortable. Sleeve covers were available, 

but most employees did not wear them. Some employees did not 

store their gloves properly between uses. We observed gloves on 

the floor, on top of chemical drums, and on top of a plunger of 

solvent. Although the company provided PPE, no written PPE 

hazard assessment and documentation of employee training had 

been completed as required by OSHA [29 CFR 1910.132].
Health Hazard Evaluation Report 2010-0031-3130 Page 9

Results

 (continued)

Half-mask N95 filtering facepiece respirators (model 8210, 3M, St. 

Paul, Minnesota) were available to employees for voluntary use. 

However, we observed employees who were improperly wearing 

and maintaining these respirators. Some employees believed that 

these respirators protected them against vapors and gases, but these 

respirators are only effective against particles.

Use of hearing protection was required in all production areas of 

the plant unless an employee intended to be in the plant for less 

than 20 minutes. However, hearing protection was required in the 

regrind department at all times. The company provided Howard 

Leight Sperian (San Diego, California) Max Lite foam insert hearing 

protectors with a noise reduction rating of 30 dB. Some employees 

were also provided with Howard Leight Model L2H earmuffs (noise 

reduction rating of 25 dB), which attached to their hardhats.

The company provided audiometric testing for all production 

employees. Previously, audiometric testing was conducted during 

the work shift in an empty house across the street from the 

Figure 4. Octave band analysis for the tote pressure wash and drum pressure wash.
Page 10 Health Hazard Evaluation Report 2010-0031-3130

Results

 (continued) plant. Personnel from the company’s corporate office performed 

audiometric tests. We were told that future audiometric testing 

will be conducted by the safety director using a Beltone (Glenview, 

Illinois) Model 119 audiometer. The audiometric test booth is 

located in the warehouse building.

The electrical outlets in the poly wash department (near the 

automatic caustic wash machine) did not contain ground fault 

circuit interrupters. Additionally, the metal of electrical outlets and 

control panels was being corroded because of humidity and caustic 

mist in the area. This corrosion could present an electrical hazard 

because of the high moisture levels in this area.

Forklift drivers did not always wear seat belts and did not 

consistently use their horns prior to turning corners from one aisle 

to another, behavior that increases the risk of injury to forklift 

drivers and other employees.

The eyewash station in the regrind department had no protective 

covers over the nozzles, which could lead to debris blocking the 

flow of water. We observed unbalanced water spray from the 

nozzles at the eyewash station in the poly wash department by the 

hydraulic pump and at other eyewash stations in the plant.

Two open vats containing rinse water (approximately 3 feet in 

height) were not labeled. We also found unlabeled containers 

of Aromatic 100 and Dissolve II, most likely because the solvent 

had removed the labels. The wall fan in the tote wash department 

where an employee wiped the outside of the totes with Aromatic 

100 was not operational during our visit.

Management at the plant held monthly “toolbox” meetings. 

These meetings covered a variety of topics, including safety issues, 

and were attended by all employees. However, the plant had no 

employee-management health and safety committee that met 

regularly to discuss health and safety concerns.
Health Hazard Evaluation Report 2010-0031-3130 Page 11

Discussion

Chemical Exposures

Breathing and skin contact are important routes of exposure to 

organic solvents, or VOCs, in the workplace. Almost all organic 

solvents cause skin irritation because they remove fat from the 

skin. Organic solvents may also irritate the respiratory system. 

This irritation is usually restricted to the upper airways, mucous 

membranes, and eyes, and it generally resolves quickly without 

long-term effects. In addition, almost all volatile, fat-soluble 

organic solvents can cause acute nonspecific central nervous system 

depression. The symptoms of significant acute solvent exposure 

are similar to those from drinking too many alcoholic beverages, 

including headache, nausea and vomiting, dizziness, slurred speech, 

impaired balance, disorientation, and confusion. These symptoms 

go away quickly when exposure stops. Although most employees 

reported no symptoms, those who did reported eye and respiratory 

irritation, which are consistent with solvent exposure. Acids and 

caustics are also irritants.

The VOC air sampling results revealed the presence of many 

different compounds in employees’ PBZs. Some of these 

compounds (cumene, xylene, and trimethyl benzene) were listed 

in the MSDS for Aromatic 100. The other VOCs we detected 

in air could have been from the volatilization of Dissolve II or 

residual chemicals in the drums. It is important to note that the 

VOC air samples are not able to measure all chemicals in the air. 

Therefore, other hazardous chemicals could have been present 

in the air during our evaluation. This would include inorganic 

decomposition products (e.g., carbon monoxide, chlorine, 

hydrogen cyanide, etc.) from the mixing of incompatible chemicals.

Except for trimethyl benzene, the PBZ concentrations of the 

aromatic hydrocarbons and sodium hydroxide were well below 

applicable OELs. The source of trimethyl benzene for the 

overexposed employee was most likely the Aromatic 100 that was 

used liberally to clean the exterior of the totes. The wall fan near 

the employee performing this activity was not operating during 

our visit so less general dilution ventilation was in the area, which 

could allow vapors to accumulate in his PBZ. This employee 

performed the same job task on the following day and was exposed 

to 83 mg/m3

 of trimethyl benzene, which is two thirds of the OEL. 

Thus, his overexposure to trimethyl benzene is not likely to be an 

unusual occurrence. The employee in the poly wash department 

who scrubbed the exterior of the drums with Dissolve II was 

exposed to around 30 mg/m3

 of trimethyl benzene on both sample 
Page 12 Health Hazard Evaluation Report 2010-0031-3130 

Discussion

 (continued) days. While these exposures are less than a quarter of the OELs, 

they suggest that Dissolve II may be another source of trimethyl 

benzene. Moreover, higher trimethyl benzene exposures could 

be expected in the warmer summer months because the plant 

does not have air conditioning, and the volatility of chemicals 

increases with rising temperatures. For example, Indiana OSHA 

measured PBZ concentrations of trimethyl benzene in the tote 

wash department during the summer (August 2010) that were more 

than twice what we measured in the same area in the spring (March 

2010) [IOSHA 2011]. Also, the chemicals in the drums vary over 

time, which could lead to a different mixture and concentration of 

chemicals in the air.

Employees at the plant have the potential for dermal exposures. 

Employees who handle Dissolve II and Aromatic 100, in particular, 

could expose their hands to aromatic and petroleum-based 

hydrocarbons if they do not wear the proper type of gloves or 

change them frequently enough. Dipropylene glycol monomethyl 

ether, a component of Dissolve II, could also present a hazard to 

poorly protected skin. The PVC gloves worn by employees were 

changed two times per week. According to the Quick Selection 

Guide to Chemical Protective Clothing [Forsberg and Mansdorf 

2007], cumene and xylene, both constituents of Aromatic 100, 

can penetrate PVC gloves in less than 1 hour. (PVC gloves were 

not evaluated against dipropylene glycol monomethyl ether.) 

Skin contact of cumene and xylene could potentially lead to skin 

problems, including contact dermatitis, or dermal absorption and 

systemic uptake of aromatic hydrocarbons [ILO 1989]. However, 

other than four cases of chemical burns in 2006, employees did not 

report having skin problems.

Noise Exposures

All monitored employees’ TWA noise exposures exceeded the 

NIOSH REL and the OSHA AL of 85 dBA. Employees using 

pressure sprayers in the poly wash and tote wash departments 

had TWA noise exposures above 100 dBA. All of these employees 

should remain in the hearing conservation program and be 

required to wear hearing protection. Until noise exposures are 

reduced to below 100 dBA, employees pressure washing drums 

and totes should be required to wear earplugs and earmuffs. 

Because we observed several employees who did not insert hearing 

protectors deeply enough into their ear canal, all employees should 

be retrained on how to properly insert earplugs. Improperly worn 
Health Hazard Evaluation Report 2010-0031-3130 Page 13

Discussion 

(continued) earplugs do not provide enough protection from noise. Supervisors 

should be responsible for observing hearing protection use and 

should help ensure the hearing protection is worn correctly.

The highest noise levels in the plant occur during pressure washing 

of drums or totes. Sound levels over 100 dBA were measured 

during these tasks and were high enough to affect noise exposures 

in adjacent work areas. For example, noise levels in the tote valve 

installer station about 25 feet from the pressure wash station 

were approximately 86 dBA when the pressure washer was not 

operating, but increased to 95 dBA when the pressure washer was 

operating. Because much of the noise generated by the pressure 

wash is high frequency, partial enclosures or barrier walls may be 

effective in reducing noise levels in adjacent areas. However, an 

enclosure would not reduce exposure for employees while pressure 

washing. Alternatively, an enclosed and automated pressure 

washing system could be designed and installed to wash the 

exterior of drums and totes. This system would protect those doing 

the job and those in adjacent areas.

We noted that several employee audiograms showed year-to-year 

variation in HTLs. While a variation of 5 to 10 dB in HTL from 

one audiogram to the next is common, an improvement in HTL 

greater than 10 dB is not a typical pattern. There may be several 

reasons for this variability. Because audiograms were conducted 

during the work shift, some employees may have had a TTS at 

the time of an audiogram, but did not have a TTS for the next 

audiogram. A TTS could occur because employees were exposed 

to noise but did not wear hearing protection before the audiogram 

or their hearing protection was not properly worn, allowing 

for substantial noise exposure. It is also possible that there was 

excessive background noise during the employee’s audiometric 

test, which may have resulted in an artificially high HTL for that 

particular test. Prior to 2009, an empty house across the street was 

used for audiometric testing.

Personal Protective Equipment Hazard 

Assessment

OSHA requires all employers to complete a comprehensive 

assessment of their workplaces to determine if hazards are present, 

or likely to be present, that would require the use of PPE such as 

safety glasses, protective gloves, safety shoes, or other PPE. Lack of 

appropriate PPE may result in injuries, including eye injuries caused 
Page 14 Health Hazard Evaluation Report 2010-0031-3130

by projected debris or chemical splashes, burns or skin injuries 

from chemical splashes, skin absorption of hazardous chemical 

agents, head or foot injuries from falling objects, lacerations from 

sharp objects or edges, and trauma from falls. Employees must also 

be trained to know when PPE must be used, what type of PPE is 

required, how to properly adjust and wear the PPE, what are the 

limitations of the PPE (e.g., what it will not protect them against), 

how to properly take care of the PPE, or in the case of disposable 

PPE, how to know when it is time to dispose of it. OSHA 

requires the employer to document in writing that the PPE hazard 

assessment and employee training have been completed.

Discussion 

(continued)

Conclusions

We measured an overexposure to trimethyl benzene in the air 

and found that skin exposure to aromatic and petroleum-based 

hydrocarbons may occur if proper gloves are not worn or changed 

frequently. Some employees reported symptoms that were 

consistent with exposures from airborne exposures to solvents. 

Most employees were exposed to high noise levels that exceeded 

NIOSH and OSHA exposure limits. Some employees were exposed 

to noise levels greater than 100 dBA, an exposure level for which 

NIOSH recommends wearing wear earplugs and earmuffs to 

protect employee hearing.

Recommendations

On the basis of our findings, we recommend the actions listed 

below to create a more healthful workplace. We encourage the 

plant to use a labor-management health and safety committee or 

working group to discuss the recommendations in this report and 

develop an action plan. Those involved in the work can best set 

priorities and assess the feasibility of our recommendations for the 

specific situation at the plant. Our recommendations are based 

on the hierarchy of controls approach (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.
Health Hazard Evaluation Report 2010-0031-3130 Page 15

Elimination and Substitution

Elimination or substitution of a toxic/hazardous process material 

is a highly effective means for reducing hazards. Incorporating 

this strategy into the design or development phase of a project, 

commonly referred to as “prevention through design” is most 

effective because it reduces the need for additional controls in the 

future.

1. Substitute Aromatic 100 with a less hazardous solvent for 

cleaning the outside of totes and drums. Aromatic 100 was the 

primary source for the trimethyl benzene that led to an employee 

being overexposed in the tote wash department. 

Engineering Controls

Engineering controls reduce exposures to employees by removing 

the hazard from the process or placing a barrier between the 

hazard and the employee. Engineering controls are very effective 

at protecting employees without placing primary responsibility of 

implementation on the employee.

1. Add local exhaust ventilation to the work areas where drums and 

totes are emptied and cleaned. Although we identified only an 

overexposure to trimethyl benzene, other hazardous chemicals in 

the drums could volatilize into the air. A downdraft or crossdraft 

exhaust ventilation system would remove potentially hazardous 

vapors and gases at the floor level before they are able to reach 

the PBZs of the employees.

2. Install an exhaust hood over the drums used to collect residual 

waste emptied from the totes. An exhaust hood would remove 

potentially hazardous chemicals that evaporate from the drums.

3. Partially enclose or install barrier walls in the noisiest areas 

of the plant (i.e., where drums and totes are pressure washed) 

to reduce noise levels in adjacent work areas. Alternatively, 

an enclosed and automated pressure washing system could be 

designed and installed to wash the exterior of drums and totes.

4. Install electrical outlets containing ground fault circuit 

interrupters in the poly wash department (near the automatic 

caustic wash machine) to prevent electrical hazards.

Recommendations

 (continued)
Page 16 Health Hazard Evaluation Report 2010-0031-3130

5. Add protective covers to the nozzles of eyewash stations and 

ensure an evenly distributed flow of water between nozzles for 

all eyewash stations. In addition, inspect and test the eyewash 

stations monthly to ensure they work properly and document 

that they have been tested.

Administrative Controls

Administrative controls are management-dictated work practices, 

policies, and programs to reduce or prevent exposures to workplace 

hazards. The effectiveness of administrative controls is dependent 

on management commitment and employee acceptance. Regular 

monitoring and reinforcement are necessary to ensure that control 

policies and procedures are not circumvented in the name of 

convenience or production.

1. Follow the recommendations from Indiana OSHA to segregate 

the cleaning of drums and totes according to the types of 

chemicals they contain to prevent exothermic reactions or 

the release of hazardous decomposition products. This would 

also facilitate the proper neutralization, disposal, and hazard 

communication requirements of the collected materials [IOSHA 

2011].

2. Add labels to the unlabeled vats containing rinse water in the 

poly wash department. This informs employees and emergency 

personnel about the contents of the vats.

3. Add laminated tags to the unlabeled containers of Aromatic 

100 and Dissolve II to identify the contents and provide health 

hazard warning information. This information helps protect 

employees and prevent misuse of the products. The solvent 

should not cause the tags to fall off.

4. Start an employee-management health and safety committee that 

meets regularly to discuss health and safety concerns.

Personal Protective Equipment

PPE is the least effective means for controlling employee exposures. 

Proper use of PPE requires a comprehensive program, and calls 

for a high level of employee involvement and commitment to be 

effective. The use of PPE requires the choice of the appropriate 

equipment to reduce the hazard and the development of 

supporting programs such as training, change-out schedules, 

Recommendations

 (continued)
Health Hazard Evaluation Report 2010-0031-3130 Page 17

and medical assessment if needed. PPE should not be relied upon 

as the sole method for limiting employee exposures. Rather, PPE 

should be used until engineering and administrative controls can be 

demonstrated to be effective in limiting exposures to acceptable levels.

1. Conduct a comprehensive hazard assessment to facilitate the 

selection of PPE as required by OSHA [29 CFR 1910.132]. 

Compliance assistance and guidelines for hazard assessment and 

PPE selection are provided in 29 CFR 1910 Subpart I Appendix 

B. OSHA eTools, available at http://www.osha.gov/dts/osta/

oshasoft/, provides additional resources for PPE selection. 

Indiana OSHA has a free consultation program called INSafe, 

available at http://www.in.gov/dol/2379.htm that could provide 

assistance with the PPE hazard assessment. Document that 

the PPE hazard assessment and employee training have been 

completed.

2. Retrain employees on how to properly wear and maintain PPE, 

including hearing protection, gloves, sleeve covers, and safety 

glasses. Supervisors should be responsible for observing and 

ensuring the correct use of PPE.

3. Choose new gloves for employees who handle Aromatic 100 and 

Dissolve II. The PVC gloves currently used are not protective 

against aromatic hydrocarbons (breakthrough of cumene and 

xylene in less than 1 hour is possible). The Quick Selection 

Guide to Chemical Protective Clothing [Forsberg and Mansdorf 

2007] provides information that can be used in selecting more 

protective gloves and change-out schedules. On the basis of 

protection and cost of gloves, we recommend using thick (>10 

millimeter) nitrile gloves and, at a minimum, changing out 

these gloves midway through the workday (after lunch). Gloves 

should also be rinsed and stored properly (away from chemicals) 

between uses.

4. Require employees who pressure wash drums and totes to wear 

earplugs and earmuffs until their TWA noise exposures are 

reduced to below 100 dBA.

5. Stop using N95 filtering facepiece respirators. These respirators 

are intended for particle exposures. During our evaluations, 

we did not observe particle exposures. If particle exposures are 

occurring and the PBZ concentrations are below applicable 

OELs, then these respirators can be provided for voluntary 

Recommendations

 (continued)
Page 18 Health Hazard Evaluation Report 2010-0031-3130

References

ACGIH [2010]. Threshold limit values for chemical substances and 

physical agents and biological exposure indices. Cincinnati, OH: 

American Conference of Governmental Industrial Hygienists.

CFR. Code of Federal Regulations. Washington, DC: U.S. 

Government Printing Office, Office of the Federal Register.

Forsberg K, Mansdorf SZ [2007]. Quick Selection Guide to 

Chemical Protective Clothing Fifth Edition. Hoboken, NJ: 

Wiley-Interscience.

ILO [1989]. Hydrocarbons, aromatic. In: Stellman JM, ed. 

International Labour Office encyclopaedia. 4th ed. Geneva, 

Switzerland: International Labour Office (ILO).

IOSHA [2011]. Safety order and notification of penalty. 

Indianapolis, IN: Indiana Department of Labor, Indiana 

Occupational Safety and Health Administration (IOSHA) 

Publication No. 313128068. [http://www.osha.gov/pls/imis/

establishment.html]. Date accessed: April 2011.

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

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

Services, Centers for Disease Control and Prevention, National 

Institute for Occupational Safety and Health (NIOSH) Publication 

No. 2005-149.

use. However, employees should be told that these respirators 

do not provide protection against vapors or gases. In addition, 

employees should be trained on the proper wear and 

maintenance of such respirators. Although a written respiratory 

protection program is not mandatory for voluntary use of 

respirators with this level of protection, OSHA requires that 

employees be provided a copy of Appendix D, “Information for 

Employees Using Respirators When Not Required Under the 

Standard,” of the OSHA Respiratory Protection Standard [29 

CFR 1910.134].

Recommendations

 (continued)
Health Hazard Evaluation Report 2010-0031-3130 Page 19

Appendix A: Methods

Air Sampling for Volatile Organic Compounds

Thermal desorption tubes were used to sample air in the PBZs of the employees. The thermal desorption 

tubes contained three beds of sorbent material: (1) 90 mg of CarbopackTM Y, (2) 115 mg of Carbopack 

B, and (3) 150 mg of CarboxenTM. Calibrated Aircheck 2000 pumps (SKC Incorporated, Eighty Four, 

Pennsylvania) were used for drawing airflows of 50 cc/min through the sampling media. The samples were 

qualitatively analyzed for various VOCs according to NIOSH Method 2549 [NIOSH 2011].

Air Sampling for Aromatic Hydrocarbons

Charcoal tubes (100 mg/50 mg) were used to sample air in the PBZs of the employees. Calibrated SKC 

Aircheck 2000 pumps pulled 200 cc/min of air through the sampling media. The samples were analyzed 

for cumene, ethylbenzene, naphthalene, toluene, trimethyl benzene, xylene, and benzene according to 

NIOSH Method 1501 [NIOSH 2011].

Noise Sampling

Larson-Davis (Provo, Utah) Spark® 705P noise dosimeters were worn by employees while they performed 

their daily activities. The noise dosimeters were attached to the wearers’ belts, and small remote 

microphones were fastened to the wearers’ shirts at a point midway between the ear and the outside of the 

shoulder. Windscreens provided by the dosimeter manufacturer were placed over the microphones during 

measurements to reduce or eliminate artifact noise, which can occur if objects bump against an unprotected 

microphone. The dosimeters were set up to collect data using different settings so that we could directly 

compare the noise measurement results with the three different noise exposure limits referenced in this 

HHE, the OSHA PEL and AL, and the NIOSH REL. OSHA uses a 90-dBA criterion and a 5-dB exchange 

rate. The difference between the OSHA PEL and AL is the threshold level used for each. The PEL has a 90-

dBA threshold, and the AL has an 80-dBA threshold. NIOSH has an 85-dBA criterion and uses a 80-dBA 

threshold. During noise dosimetry measurements, noise levels below the threshold level are not integrated 

by the dosimeter for accumulation of dose and calculation of TWA noise level. 

The dosimeters averaged noise levels every second during monitoring. At the end of the sampling period, 

the dosimeters were removed and paused to stop data collection. The noise measurement information 

stored in the dosimeters was downloaded to a personal computer for interpretation with Larson Davis 

Blaze® computer software. The dosimeters were calibrated before and after the measurement periods 

according to the manufacturer’s instructions.

Area noise levels and octave band frequency spectrum analysis (measurement of noise in different 

frequencies) were measured with System 824 SLM and real-time frequency analyzers (Larson-Davis, Provo, 

Utah). The SLMs were equipped with 0.5-inch random incidence Type 1 electret microphones and the 

instruments measured noise levels between 16 and 157 dBA. The SLMs were calibrated before and after 

the measurement periods according to the manufacturer’s instructions. SLMs were either handheld or 

mounted on a tripod at a height of approximately 5 feet.
Page 20 Health Hazard Evaluation Report 2010-0031-3130

Appendix A: Methods

 (continued)

References

NIOSH [2011]. NIOSH manual of analytical methods. 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 No. 94-113 (August 

1994); 1st Supplement Publication 96-135, 2nd Supplement Publication 98-119, 3rd Supplement 

Publication 2003-154. [http://www.cdc.gov/niosh/docs/2003-154/]. Date accessed: April 2011.
Health Hazard Evaluation Report 2010-0031-3130 Page 21

Appendix B: Occupational Exposure Limits and Health Effects

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 that most employees may be exposed to for 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 preexisting 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 adverse 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. Some chemical substances and physical agents have recommended STEL 

or ceiling values where adverse 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.

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 of 1970. 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 United States 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 

2010]. WEELs have been established for some chemicals “when no other legal or authoritative limits 

exist” [AIHA 2010].
Page 22 Health Hazard Evaluation Report 2010-0031-3130

Appendix B: Occupational Exposure Limits and Health Effects

 (continued)

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

and include both legal and recommended limits. The Institut für Arbeitsschutz der Deutschen 

Gesetzlichen Unfallversicherung (IFA, Institute for Occupational Safety and Health of the German 

Social Accident Insurance) maintains a database of international OELs from European Union 

member states, Canada (Québec), Japan, Switzerland, and the United States. The database, available at 

http://www.dguv.de/ifa/en/gestis/limit_values/index.jsp, contains international limits for over 1,500 

hazardous substances and is updated periodically.

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 assessments 

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 on control 

banding is available at http://www.cdc.gov/niosh/topics/ctrlbanding/. This approach can be applied 

in situations where OELs have not been established or can be used to supplement the OELs, when 

available.

A PBZ concentration of trimethyl benzene and several personal noise exposures exceeded applicable 

OELs. The PBZ concentrations of the other compounds we sampled were well below their applicable 

OELs. Therefore, we only discuss the potential health effects from exposure to trimethyl benzene and 

noise. However, health effect information for the other compounds is available at http://www.cdc.

gov/niosh/ipcs/nicstart.html.

Trimethyl Benzene

Short-term exposures to trimethyl benzene can cause irritation to the eyes, skin, and respiratory tract. 

Long-term exposures can defat the skin, and cause chronic bronchitis and adverse effects on the 

blood and central nervous systems [IPCS 2002]. The NIOSH REL and ACGIH TLV for trimethyl 

benzene pertains to the three isomers (1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, and 1,2,3-

trimethyl benzene). The NIOSH REL for trimethyl benzene was adopted from the OSHA PEL of 

125 mg/m3

 that was established for the three isomers of trimethyl benzene in 1989, but vacated by 
Health Hazard Evaluation Report 2010-0031-3130 Page 23

Appendix B: Occupational Exposure Limits and Health Effects 

(continued)

the 11th Circuit Court of Appeals in 1992 [NIOSH 2005]. Nevertheless, OSHA can use the 1989 

PEL (current NIOSH REL) for trimethyl benzene to justify violations of the “general duty clause” as 

contained in Section 5(a) (1) of the Occupational Safety and Health Act [29 USC 1900]. The ACGIH 

TLV is intended to minimize changes to the central nervous system, asthmatic bronchitis, and blood 

dyscrasias (an abnormal blood condition) [ACGIH 2001]. The latter health effect could be due to the 

contamination of trimethyl benzene with benzene. For this reason it is important to measure benzene 

when products containing trimethyl benzene are being used [ACGIH 2001].

Noise

Noise-induced hearing loss is an irreversible, sensorineural condition that progresses with exposure. 

Although hearing ability declines with age (presbycusis), noise exposure produces more hearing loss 

than that resulting from aging alone. This noise-induced hearing loss is caused by damage to nerve 

cells of the inner ear (cochlea) and, unlike some conductive hearing disorders, cannot be treated 

medically [Berger et al. 2003]. In most cases, noise-induced hearing loss develops slowly and usually 

occurs before it is noticed. Hearing loss is often severe enough to permanently affect a person’s ability 

to hear and understand speech. For example, people with hearing loss may not be able to distinguish 

words such as “fish” from “fist.” [Suter 1978].

The dBA is the preferred unit for measuring sound levels to assess employee noise exposures. The dBA 

noise scale is weighted to approximate the sensory response of human ears to sound frequencies near 

the hearing threshold. Because the dBA scale is logarithmic, increases of 3 dBA, 10 dBA, and 20 dBA 

represent a doubling, tenfold increase, and hundredfold increase of sound energy, respectively. Noise 

exposures expressed in dBA cannot be averaged by taking the arithmetic mean.

The OSHA noise standard [29 CFR 1910.95] specifies a PEL of 90 dBA, as an 8-hour TWA. The 

OSHA PEL is calculated using a 5-dB exchange rate. This means that a person may be exposed to 

noise levels of 95 dBA for no more than 4 hours, 100 dBA for 2 hours, 105 dBA for 1 hour, etc. 

Conversely, up to 16 hours exposure to 85 dBA is allowed by this exchange rate. An employee’s daily 

noise dose, based on the duration and intensity of noise exposure, can be calculated according to the 

formula

Dose = 100 X (C1/T1 + C2/T2 + ... + Cn/Tn ),

where Cn indicates the total time of exposure at a specific noise level and Tn indicates the reference 

duration for that level as given in Table G-16a of the OSHA noise regulation. Doses greater than 100% 

are in excess of the OSHA PEL.

When noise exposures exceed the PEL of 90 dBA, OSHA requires that employees wear hearing 

protection, and that an employer implement feasible engineering or administrative controls to 

reduce noise exposures. The OSHA noise standard also requires an employer to implement a hearing 

conservation program when 8-hour TWA noise exposures exceed the AL of 85 dBA. The program 
Page 24 Health Hazard Evaluation Report 2010-0031-3130

Appendix B: Occupational Exposure Limits and Health Effects 

(continued)

must include noise monitoring, employee notification, observation, audiometric testing, hearing 

protectors, training, and record keeping.

NIOSH [NIOSH 1998] and ACGIH [ACGIH 2010] recommend an exposure limit of 85 dBA, as an 

8-hour TWA. A more conservative 3-dB exchange rate is used in calculating these exposure limits. 

Using NIOSH criteria, an employee can be exposed to 85 dBA for 8 hours, but to no more than 88 

dBA for 4 hours, 91 dBA for 2 hours, 94 dBA for 1 hour, etc. Twelve-hour exposures have to be 83.2 

dBA or less according to the NIOSH REL.

Audiometric evaluations of employees’ hearing thresholds must be conducted in quiet locations, 

preferably in a sound-attenuating booth, by presenting pure tones of varying frequencies at threshold 

levels (i.e., the level of a sound that the person can just barely hear). Zero dB HTL represents the 

hearing level of an average, young individual with good hearing. The OSHA hearing conservation 

standard requires hearing thresholds to be measured at test frequencies of 500, 1000, 2000, 3000, 

4000, and 6000 Hz. Individual employee’s annual audiograms are compared to their baseline 

audiogram to determine if an STS has occurred. OSHA states that an STS has occurred if the 

average threshold values at 2000, 3000, and 4000 Hz have increased by 10 dB or more in either ear 

when comparing the annual audiogram to the baseline audiogram [29 CFR 1910.95]. The NIOSHrecommended hearing threshold shift criterion is a 15-dB shift at any frequency in either ear from 

500–6000 Hz measured twice in succession [NIOSH 1998]. Both of these hearing threshold shift 

criteria require at least two audiometric tests.
Health Hazard Evaluation Report 2010-0031-3130 Page 25

References

ACGIH [2001]. Trimethyl benzene, isomers. In: Documentation of the threshold limit values and 

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

Hygienists.

ACGIH [2010]. Threshold limit values for chemical substances and physical agents and biological 

exposure indices. Cincinnati, OH: Arican Conference of Governmental Industrial Hygienists.

AIHA [2010]. AIHA 2010 Emergency response planning guidelines (ERPG) & workplace environmental 

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

Berger EH, Royster LH, Royster JD, Driscoll DP, Layne M, eds. [2003]. The noise manual. 5th rev. ed. 

Fairfax, VA: American Industrial Hygiene Association.

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

Federal Register.

IPCS (WHO/International Programme on Chemical Safety) [2002]. International Chemical Safety 

card: trimethyl benzene (mixed isomers). [http://www.cdc.gov/niosh/ipcsneng/neng1389.html]. Date 

accessed: April 2011.

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. Barsen ME, ed. Cincinnati, OH: U.S. 

Department of Health and Human Services, Centers for Disease Control and Prevention, National 

Institute for Occupational Safety and Health (NIOSH) Publication No. 2005-149.

Suter AH [1978]. The ability of mildly-impaired individuals to discriminate speech in noise. Washington, 

DC: U.S. Environmental Protection Agency, Joint EPA/USAF study, EPA 550/9-78-100, AMRL-TR78-4.

USC. United States Code. Washington, DC: U.S. Government Printing Office.

Appendix B: Occupational Exposure Limits and Health Effects 

(continued)
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Health Hazard Evaluation Report 2010-0031-3130 Page 27

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 not 

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 Kenneth W. Fent, Elena Page, and Scott 

E. Brueck of HETAB, Division of Surveillance, Hazard Evaluations 

and Field Studies. Industrial hygiene field assistance was provided by 

Greg Burr. Analytical support was provided by Ardith Grote. Health 

communication assistance was provided by Stefanie Evans. Editorial 

assistance was provided by Ellen Galloway. Desktop publishing was 

performed by Greg Hartle.

Copies of this report have been sent to employee and management 

representatives at the drum refurbishing plant, the Indian State 

Department of Health, the Indiana Occupational Safety and 

Health Administration, and the Occupational Safety and Health 

Administration Region 5 Office. This report is not copyrighted and 

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

at http://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 [2011]. Health hazard evaluation report: evaluation of chemical hazards 

and noise exposures at a drum refurbishing plant–Indiana. By Fent KW, Page 

E, Brueck SE. 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. 2010-0031-3130.

To receive NIOSH documents or information about 

occupational safety and health topics, contact NIOSH at:

1-800-CDC-INFO (1-800-232-4636)

TTY: 1-888-232-6348

E-mail: cdcinfo@cdc.gov

or visit the NIOSH web site at: www.cdc.gov/niosh.

For a monthly update on news at NIOSH, subscribe to 

NIOSH eNews by visiting www.cdc.gov/niosh/eNews.

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