Evaluation of Worker 

Exposures to Peracetic 

Acid-Based Sterilant 

during Endoscope 

Reprocessing

David Sylvain, MS, CIH

John Gibbins, DVM, MPH

Health Hazard Evaluation Report

HETA 2006-0298-3090

Kaleida Health–Buffalo General Hospital

Buffalo, New York

August 2009

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 2006-0298-3090 Page i

Report Abbreviations.......................................................................i

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

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

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

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

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

Discussion ...........................................................................7

Conclusions.........................................................................9

Recommendations.............................................................10

References ........................................................................12

Contents

Acknowledgments Acknowledgments and Availability of Report.....................1
Page ii Health Hazard Evaluation Report 2006-0298-3090

ACGIH® American Conference of Governmental Industrial Hygienists

BGH Buffalo General Hospital

CDRH Center for Devices and Radiological Health

CFR Code of Federal Regulations

FDA United States Food and Drug Administration

HVAC Heating, ventilating, and air-conditioning

HHE Health hazard evaluation

LOD Limit of detection

mL/min milliliters per minute

NAICS North American Industry Classification System

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OPA ortho-Phthalaldehyde

OSHA Occupational Safety and Health Administration

PAA Peracetic acid

PBZ Personal breathing zone

PPE Personal protective equipment

ppm Parts per million

REL Recommended exposure limit

RH Relative humidity

SS1 Steris SYSTEM 1® Processing System

TWA Time-weighted average

Abbreviatio
Health Hazard Evaluation Report 2006-0298-3090 Page iii

What NIOSH Did

● We met with management, employees, and a union 

representative to discuss employee concerns.

● We toured the A2 GI Lab Steris Room and observed staff at 

work.

● We collected area and personal air samples for acetic and 

peracetic acids.

● We measured temperature and relative humidity.

● We used smoke tubes to observe airflow patterns in the A2 

GI Lab Steris Room.

● We spoke with employees confidentially about possible workrelated symptoms, safety and health training, use of personal 

protective equipment (PPE), chemical exposure incidents, 

and indoor environmental quality.

● We looked at Food and Drug Administration reports 

of sterilant spills, worker exposures, and injuries during 

endoscope reprocessing at other hospitals to identify possible 

causes of problems reported at this facility.

What NIOSH Found

● Concentrations of peracetic acid are thought to be low, 

although we could not measure current levels.

● Latex gloves worn while handling peracetic acid sterilant 

containers do not provide adequate protection.

● Some workers reported not using all available PPE (aprons 

and sleeve protectors) due to high temperatures in the A2 GI 

Lab Steris Room.

● Two workers reported prior chemical burns from contact 

with Steris 20 Sterilant Concentrate.

● Employees did not receive adequate training in chemical 

hazard communication and in standard operating procedures 

for chemical spills, leaks, and processor malfunctions. 

● Ventilation in the A2 GI Lab Steris Room was inadequate.

● Exposure to peracetic acid sterilant is unlikely when Steris 

processors are maintained and operated properly and when 

technicians follow the manufacturer’s operating procedures.

In July 2006, the National 

Institute for Occupational 

Safety and Health (NIOSH) 

received a confidential 

health hazard evaluation 

(HHE) request from 

employees at Kaleida 

Health-Buffalo General 

Hospital in Buffalo, New 

York. The HHE request 

stated that inadequate 

ventilation was provided 

in the A2 GI Lab Steris 

Room where five 

employees clean and 

sterilize endoscopes 

using Klenzyme® 

Enzymatic Cleaner and 

Steris® 20 Sterilant 

Concentrate. Health 

problems identified in the 

request were headache, 

shortness of breath, eye 

irritation, and diminished 

sense of smell. We 

conducted a site visit on 

December 18–19, 2006.

Highlights of 

NIOSH 

Hazard Eval
Page iv Health Hazard Evaluation Report 2006-0298-3090

Highlights of 

NIOSH 

Hazard Eval

(continued

What Hospital Managers Can Do

● Require use of appropriate PPE to prevent eye, face, hand, 

arm, and body contact with concentrated peracetic acid 

as well as other cleaning chemicals and contaminated 

equipment.

● Provide hazard communication training for A2 GI Lab Steris 

Room employees.

● Train employees in standard operating procedures for spills, 

leaks, and processor malfunctions.

● Ask Steris Corporation to provide new employee and annual 

refresher inservice training.

● Make sure that processors are inspected periodically for worn 

parts that can cause leaks.

● Notify Steris Corporation of leaks and equipment problems.

● Increase ventilation in the A2 GI Lab Steris Room for odor 

control and the comfort of the workers.

What Steris Room Employees Can Do

● Wear tight-fitting splash-resistant goggles and acid-resistant 

gloves, sleeves, and apron when handling sealed Steris cups 

during normal operations.

● Wear a face shield over eye protection along with routine 

PPE when handling or disposing of a cup that is not 

completely empty.

● Follow the manufacturer’s instructions for handling Steris 

cups and operating processors.

● Tell management about problems with processors or Steris 

cups, or if you notice worn processor seals or other parts.

● Follow standard operating procedures for processor 

problems, leaks, and sterilant spills.

● Participate in training when provided.
Health Hazard Evaluation Report 2006-0298-3090 Page v

In July 2006, NIOSH received a confidential HHE request from 

employees at Kaleida Health-Buffalo General Hospital in Buffalo, 

New York. The HHE request stated that inadequate ventilation was 

provided in the A2 GI Lab Steris Room where five employees clean 

and sterilize endoscopes with Klenzyme® Enzymatic Cleaner and 

Steris® 20 Sterilant Concentrate. Health problems identified in 

the request were headache, shortness of breath, eye irritation, and 

diminished sense of smell.

On December 18–19, 2006, we conducted a site visit that included 

an opening conference, a walk-through of the A2 GI Lab Steris 

Room, air sampling for peracetic and acetic acids, measurements 

of temperature and RH, smoke tube visualization of airflow, and 

confidential informal interviews with several employees.

Air samples did not contain detectable concentrations of acetic 

acid. Sampling results and our onsite observations indicate very 

little, if any, airborne exposure to peracetic acid sterilant on the 

sampling date. The temperature was 74oF to 76oF, and the RH was 

17% to 20%. Smoke tube visualization of airflow at the ceilingmounted ventilation supply diffusers and return grilles in the 

Steris room indicated that the HVAC system provided insufficient 

airflow. Ventilation in the Steris room appeared to be inadequate 

for providing reliable odor control and maintaining the work 

environment within an acceptable range of temperature and RH.

Employees reported periodic headaches and burning eyes that 

were more noticeable when SS1 processors malfunctioned and 

leaked. Poor ventilation and high environmental temperatures 

were noted by workers. Although gloves, sleeves and aprons are 

provided, some workers reported not using all available PPE due 

to high environmental temperatures. Two workers reported prior 

chemical burns from occupational exposure to Steris 20 Sterilant 

Concentrate. Several workers reported that they had not received 

formal chemical hazard communication training for Steris room 

operations.

A review of FDA CDRH data files indicated that occupational 

exposure to peracetic acid sterilant should be unlikely when 

SS1 processors are maintained and operated properly and when 

technicians follow the manufacturer’s operating procedures. 

However, processor malfunctions and improper handling and 

disposal of Steris 20 Sterilant Concentrate containers can result 

in dermal or inhalation exposures. Appropriate employee training, 

Exposure to peracetic 

acid sterilant is unlikely 

when SS1 processors 

are maintained and 

operated properly and 

when technicians follow 

the manufacturer’s 

operating procedures. 

Processor malfunctions, 

and improper handling 

and disposal of Steris 

20 Sterilant Concentrate 

containers can result 

in dermal or inhalation 

exposures.

Summ
Page vi Health Hazard Evaluation Report 2006-0298-3090

Summa   (continued) use of adequate PPE, and routine maintenance of process

should help reduce the likelihood of worker exposures, as well as 

the risk of employee illness or injury if a spill or leak does occur.

Keywords: NAICS 622110 (General Medical and Surgical 

Hospitals), endoscope reprocessing, endoscope sterilization, 

peracetic acid, anosmia, chemical burns, dyspnea, eye irritation, 

sense of smell, shortness of breath.
Health Hazard Evaluation Report 2006-0298-3090 Page 1

Introduct

In July 2006, NIOSH received a confidential HHE request from 

employees at Kaleida Health-Buffalo General Hospital in Buffalo, 

New York. The HHE request stated that inadequate ventilation was 

provided in the A2 GI Lab Steris Room where five employees clean 

and sterilize endoscopes using Klenzyme® Enzymatic Cleaner and 

Steris® 20 Sterilant Concentrate. Health problems identified in 

the request were headache, shortness of breath, eye irritation, and 

diminished sense of smell.

Background

Management representatives told us that SS1 had been used 

at BGH for approximately 10 years prior to our site visit. SS1 

was introduced into BGH as a replacement for ethylene oxide 

sterilization. During the opening conference, management noted 

that health complaints from employees in the A2 GI Lab Steris 

Room began in approximately May 2006, following renovations 

in that area. Full-shift air sampling conducted by a consultant 

in June 2006 indicated that airborne concentrations of acetic 

acid were less than 0.2 ppm. Although management was not 

aware of spills involving SS1 processors, employees had reported 

occasional leaks. In November 2006, SS1 processors were inspected 

by a representative from Steris Corporation who identified no 

problems.

The A2 GI Lab Steris Room is one of several Steris rooms at BGH. 

Although referred to as a single room, the A2 GI Lab Steris Room 

is divided into two small rooms (“dirty side” and “clean side,” 

which are separated by a floor-to-ceiling wall with a sliding window. 

The dirty side adjoins a hospital corridor along a 6-foot wall, which 

has a single doorway for entry. The length of the room extends 

approximately 15 feet from the corridor. The dirty side contains a 

stainless steel counter and sink along the 15-foot wall that separates 

the dirty and clean sides. The window between these rooms is 

located a few feet from the most interior wall. Each of these rooms 

has a plumbed eyewash station.

The clean side is approximately 10 feet wide by 15 feet long, with a 

single doorway to the corridor. Three SS1 processors are installed 

on a stainless steel counter near the window between the dirty and 

clean sides. Two processors are located along the back wall and 

one along the wall opposite the window. Also along this wall is a 

GUS® Model G17HS endoscope immersion unit, which contains 

approximately one-half gallon of Cidex® OPA Solution. The GUS 

unit is a compact, ductless vapor control system that exhausts into 

the room via a carbon filter. It is our understanding that the GUS 
Page 2 Health Hazard Evaluation Report 2006-0298-3090

Introducti

(continued) unit is used infrequently for endoscope disinfection; however,

Cidex OPA remains in the unit at all times.

A canopy hood is mounted on the ceiling of the clean side against 

the wall separating the two small rooms and the most interior 

(back) wall (the hood is open on two sides). The sides of the hood 

extend downward to within approximately 4 feet above four of the 

six processors. The Steris room is provided with ceiling diffusers 

and returns for general ventilation. Facilities staff informed us that 

the Steris room is supplied with 100% outside air.

When an endoscopic procedure is completed, the endoscope is 

brought to the dirty side where a technician manually cleans it 

using Klenzyme® enzymatic cleaner. After cleaning, the endoscope 

is passed through the sliding window to a technician in the clean 

side. The clean side technician installs the appropriate channel 

connectors, places the endoscope in a processing tray in one of 

the SS1 processors along with a sealed container of Steris 20 

Sterilant Concentrate, closes the processor lid, and starts the 

microprocessor-controlled operating cycle. When the approximately 

30-minute sterilization cycle is finished, the technician opens the 

processor, removes the endoscope, flushes it with 120 milliliters 

of isopropyl alcohol, and purges cavities within the endoscope 

with forced air to remove the alcohol. This procedure is repeated 

for each endoscope that is returned for cleaning and sterilization. 

More than one processor may be operating at any given time. The 

Figure 1. Steris System 1® processor in operation 
Health Hazard Evaluation Report 2006-0298-3090 Page 3

Introductin  (contin

only PPE that we observed being worn in the clean side during our 

site visit was latex gloves.

Each SS1 processor is a fully-enclosed tabletop unit. Steris 20 

Sterilant Concentrate is provided in sealed single-use containers 

(“cups”) that hold 2.02 fluid ounces (67.5 grams) of liquid and 

163.7 grams of powder. The composition of the liquid (% by 

volume) is 35.5% peracetic acid, 40.0% acetic acid, 6.5% hydrogen 

peroxide, and 1.0% sulfuric acid [Steris 1995]. The solid powder 

consists of proprietary builders and buffers [Alfa 2004; Steris 

2007]. During the sterilization cycle, the processor aspirates 

the concentrated liquid sterilant, and dilutes it to a working 

concentration of 0.2% PAA at a pH of 6.4 and a temperature 

of 50oC to 56oC [Alfa 2004; Steris 2007]. When diluted, PAA 

hydrolyzes to acetic acid and hydrogen peroxide with a half-life 

of less than 20 minutes at 50oC [Steris 1995]. The 0.2 % PAA 

solution circulates around and through the endoscope for 12 

minutes before being discharged into the sewer system. After the 

sterilant has been discharged from the processor, the processor 

flushes the endoscope four times with filtered water [Alfa 2004; 

Steris 2007; Steris 2008]. The technician can open the processor 

after the final rinse water has been discharged down the drain.

Figure 2. Row of Steris System 1® processors 
Page 4 Health Hazard Evaluation Report 2006-0298-3090

Introducti

(continued

Contact with Steris 20 Sterilant Concentrate can cause severe 

irritation and burns to eyes and skin. Animal studies indicate 

that Steris 20 Sterilant Concentrate may be a sensitizer [Steris 

1995]. Inhalation of PAA vapor may cause pulmonary edema and 

sensitization [IPCS 1994a; Sciencelab.com 2005]. No OELs have 

been established for PAA [NJDHSS 1998a].

Contact with acetic acid can cause severe irritation and burns 

to the eyes and skin. Inhalation exposure can cause respiratory 

irritation, bronchitis, pharyngeal edema, and pulmonary edema 

[IPCS 1994b; Hathaway et al. 1996; NJDHSS 1998b]. The NIOSH 

REL for acetic acid is 10 ppm for up to 10 hours per workday 

during a 40-hour workweek. OSHA and ACGIH have established 

8-hour TWA OELs of 10 ppm for acetic acid. In addition, NIOSH 

and ACGIH recommend that exposures to acetic acid not exceed 

15 ppm during any 15-minute exposure during the course of the 

day (short-term exposure limit) [ACGIH 2009; NIOSH 1992]. The 

odor threshold for acetic acid is reported to be approximately 0.48 

to 1.0 ppm [NJDHSS 1998b].

In response to the HHE request, we conducted a site visit on 

December 18–19, 2006. The evaluation included an opening 

conference, a walk-through of the A2 GI Lab Steris Room, 

Figure 3. Steris System 1® processor in operation showing Steris 20 

Sterilant Concentrate container in lower right corner of the processor. 

Assessment
Health Hazard Evaluation Report 2006-0298-3090 Page 5

Assessment (continued) air sampling for peracetic and acetic acids, measurements of

temperature and RH, and confidential informal interviews with 

several employees.

Full-shift PBZ air samples were collected for each of the three 

technicians who were working in the Steris room on December 

19. Two area air samples were collected in the clean side. One 

area air sample was collected in the dirty side at the open window 

between the dirty and clean sides. Air samples were collected on 

ORBOTM 53 activated silica gel tubes at a nominal flow rate of 100 

mL/min. Samples were analyzed for PAA and acetic acid by high 

performance liquid chromatography according to a NIOSH draft 

method. Draeger® short-term colorimetric detection tubes were 

used to measure the airborne concentration of acetic acid in the 

clean side while four processors were in operation. These tubes 

have a standard measurement range of 5 to 80 ppm during a 30 

second sampling period [Draeger 2009].

Temperature and RH were measured in the clean side using a 

hand-held, battery operated, TSI Model 8722 TH-CalcTM Thermal 

Hygrometer (TSI Inc., Shoreview, Minnesota). This instrument 

measures temperature and RH in the ranges of 32oF to 140oF and 

5% to 95% RH. A ventilation smoke tube was used to visualize 

airflow patterns within the Steris room and to determine if the 

clean and dirty sides were under positive or negative pressure 

relative to each other and to the adjoining corridor.

Confidential, voluntary interviews were conducted with employees 

who work in the A2 GI Lab Steris Room. Employees were asked 

about potential work-related health symptoms, safety and health 

training, PPE use, chemical exposure incidents, and indoor 

environmental quality.

Industrial Hygiene

Air samples did not contain detectable concentrations of acetic 

acid. The analytical LOD for acetic acid in the air samples was 

approximately 25 micrograms of acetic acid per sample [Neumeister 

2009]. Based on the LOD and the average volume of the PBZ 

samples (20.1 liters), acetic acid concentrations in these samples 

were no greater than 0.5 ppm. The three area air samples, which 

had an average sample volume of 43 liters, indicated that acetic 

acid concentrations were no greater than 0.24 ppm. Draeger 

colorimetric detector tubes did not detect acetic acid in the clean 

side.

Results
Page 6 Health Hazard Evaluation Report 2006-0298-3090

Results (continued) We attempted to quantitate PAA using a draft NIOSH method

originally intended for acetic acid; however, PAA coeluted with 

the solvent front during analysis, which prevented separation and 

quantitation of PAA. Further efforts to resolve PAA in the samples 

were not made because (1) acetic acid (a major component of Steris 

20 sterilant) was not detected above the LOD; (2) although PAA 

coeleuted with the solvent front, the area of the chromatogram 

peak was consistent with the area of the blank samples, 

indicating that PAA was not present in large quantity; and (3) 

no acid odor was detected during the sampling visit [Neumeister 

2009].

Temperatures in the clean side between 8:50 a.m. and 1:15 p.m. 

were 74oF to 76oF, and RH was between 17% and 20%. Smoke 

tube visualization of airflow at the ceiling-mounted ventilation 

supply diffusers and return grilles in the clean side indicated that 

the HVAC system provided insufficient airflow. No air appeared 

to be coming from the supply diffusers. The open doors between 

the Steris room and the corridor served as the source of makeup air for the canopy hood; there was no other source of outside 

air. The dirty side appeared to be under slight negative pressure 

relative to the corridor, while the clean side was under negative 

pressure relative to the corridor and the dirty side, causing air 

to flow toward the clean side and out through the canopy hood. 

Turbulence beneath the canopy hood in the clean side caused 

smoke to drift away from the Steris processors, rather than being 

immediately captured and exhausted by the hood.

Interviews

Confidential, voluntary interviews were conducted with four of five 

employees who work in the A2 GI Lab Steris Room; one employee 

was on extended family leave and not available to participate. The 

median length of employment at BGH was 14 years; however, the 

median length of employment in the A2 GI Lab Steris Room was 

13 months, and three of the four employees had worked in the 

department less than 14 months. Workers reported no formalized, 

documented initial or refresher hazard communication training 

in their current assignment at BGH; however, such training had 

been provided when they were employed in other sections of the 

hospital. On-the-job training was provided by coworkers with 

longer tenure in the department; however, two of four employees 

did not know the proper procedures for responding to a chemical 

spill or SS1 processor malfunction and overflow.
Health Hazard Evaluation Report 2006-0298-3090 Page 7

Results (continued) Three employees reported periodic headaches and burning eyes;

these symptoms were worse when the processors malfunctioned 

and overflowed, or when excessive liquid was left in the bottom 

of the machine after completion of a sterilization cycle. Poor 

ventilation and high environmental temperatures were common 

complaints among workers; these conditions were reportedly 

worse during the summer. Workers reported leaving the doors 

between both sides of the Steris rooms and the corridor open to 

improve ventilation, but are instructed by supervisors to keep these 

doors closed, reportedly due to odor complaints from patients 

and nursing staff. PPE in the form of chemically resistant, sleeve 

protectors and aprons are provided by management; however, 

some workers reported not using all available PPE due to high 

environmental temperatures. Two workers reported having had 

chemical burns from prior use of Steris 20 Sterilant Concentrate.

On the day of our site visit, we did not smell an acid odor, which 

we would have noticed if airborne acid vapor concentrations had 

approached the OELs for acetic acid. This observation is consistent 

with air sampling results, which indicate that airborne levels of 

acetic acid were below the analytical LOD. Although exposure 

limits have not been established for PAA, the sampling results and 

our onsite observations indicated little, if any, airborne exposure to 

PAA on the sampling date.

Although we do not know the specific sources of odors reportedly 

emitted from the Steris room, odor complaints from patients and 

nursing staff suggest that the ventilation in the Steris room is 

inadequate. Odor complaints, worker reports of uncomfortably 

warm temperatures especially during the summer, and our 

observations during the site visit point to a need for increasing the 

general ventilation in the Steris room.

While Klenzyme Concentrate Plus Enzymatic Cleaner and 

Cidex OPA Solution were not the focus of this investigation, 

it is important to note hazards associated with these products. 

Klenzyme, which can irritate the skin and eyes, contains proteolytic 

enzymes, also known as subtilisins. Subtilisins in powder form 

are a known respiratory sensitizer. In 2001, researchers reported 

a case of extrinsic allergic alveolitis in a hospital worker who was 

exposed to subtilisins in Klenzyme that the worker used to wash 

surgical instruments and clean operating room surfaces [Tripathi 

and Grammer 2001]. OPA is an eye, skin, and respiratory irritant 

that may also cause sensitization [Advanced Sterilization Products 

2007]. A 2006 article describes a case of occupational asthma and 

Discussi
Page 8 Health Hazard Evaluation Report 2006-0298-3090

Discussio  (continued) dermatitis that is believed to be due to exposure to OPA in 

endoscopy unit [Fujita et al. 2006]. BGH employees and managers 

should be aware of the hazards associated with these materials.

The FDA CDRH maintains Adverse Event Reporting Data Files 

that consist of voluntary reports, user facility reports, distributor 

reports, and manufacturer reports of medical devices that may 

have malfunctioned or caused a death or serious injury [USFDA 

2009]. To better understand workplace hazards during endoscope 

reprocessing, we searched the online CDRH data files for adverse 

event reports received in 1996 through 2008 that involved SS1. 

Reports involving SS1 were reviewed to identify factors related to 

worker safety and health at all medical facilities that had submitted 

reports, or that were described in reports.

Steris 20 Sterilant Concentrate was involved in approximately 

50% of the 63 adverse event reports identified during our review. 

Worker exposure was noted in all but one of these reports. 

More than 80% of reported exposures to concentrated PAA 

sterilant resulted in worker injury; most of these incidents 

occurred while handling a sealed Steris 20 Sterilant Concentrate 

cup prior to placing the cup into a processor, or while disposing 

of incompletely emptied cups at the end of a sterilization cycle. 

The most common type of injury was a chemical burn of the skin, 

which varied from what appeared to be minor burns, to several 

reports of second degree burns, and at least one report of a third 

degree burn. Several instances of eye contact that reportedly 

resulted in burns and pain were identified. Respiratory exposures 

to concentrated PAA sterilant resulted in reports of shortness of 

breath; nasal irritation and scabbing of nasal passages; and rare 

events, including lung hypertension and pneumonia, and an 

asthmatic-like reaction in a hospital receptionist.

Eight reports noted that hospital workers were burned when the 

seal on unopened cups ruptured as the workers squeezed the cups 

to break up powdered buffers. As reported in three manufacturer 

narratives, the manufacturer’s instructions state that “powders 

can be broken up by gently squeezing the bottom portion of the 

Steris 20 container.” The manufacturer narratives attributed these 

incidents to improper handling by the workers. These incidents 

resulted in reports of burns on hands, arm, eyes, face, neck, 

and abdomen. In one instance, concentrated PAA sterilant was 

reportedly splashed onto the eyes, face, and neck of a bystander. 

In two instances, a cup lid “popped” or leaked as a cup was being 

removed from its carton.
Health Hazard Evaluation Report 2006-0298-3090 Page 9

Discussio  (continued) Ten reports described incidents involving disposal of cups th

had expired, or that had not been completely emptied during 

a sterilization cycle. In most cases, the exposure occurred to 

the worker who was disposing of the cup; however, two reports 

noted burns due to contact with concentrated sterilant spilled on 

work surfaces or furniture, and in one instance, a housekeeping 

employee reported shortness of breath that was attributed to 

a Steris cup that had been thrown in the trash. Other reports 

describe skin and eye contact with concentrated sterilant as a result 

of cup leaks, improper sterilant storage, and spray released while 

inserting or removing the SS1 aspirator into/from the sterilant 

cup.

Only eight reports were identified in which PPE was mentioned. 

Of these, five noted that PPE had not been used by the exposed 

worker, and two indicated that the PPE was inadequate. Based on 

the descriptions of dermal and eye exposures to concentrated PAA 

sterilant, it appears that worker injuries could have been prevented 

if appropriate PPE had been used.

Twenty-five reports appear to involve releases of 0.2% PAA sterilant 

(“use dilution”) from SS1 processors. Failure of the inflatable 

processor lid seal was reported as the cause of most processor leaks. 

Other leaks occurred when the processor lid opened suddenly 

during a sterilization cycle, or when defective endoscope trays 

were used. Only six releases of dilute sterilant resulted in reports 

of worker exposure. Four reports identified health effects such as 

eye, skin, or respiratory irritation. Two reports of exposure during 

cleanup of dilute sterilant described respiratory difficulties: in one 

instance, a worker was treated with a nebulizer after cleaning a 

dilute sterilant spill for 10 minutes, and in the second instance, a 

worker was treated for reactive airways dysfunction syndrome after 

cleaning a spill for 15 minutes.

Exposure to peracetic acid sterilant is unlikely when SS1 processors 

are maintained and operated properly, and technicians follow 

the manufacturer’s operating procedures; however, processor 

malfunctions, improper handling and disposal of Steris 20 

Sterilant Concentrate containers, and nonroutine events can result 

in dermal or inhalation exposures. Even though the sterilant cups 

are designed to prevent exposure to PAA sterilant, rough handling 

and accidental or forceful squeezing can result in exposure to 

the concentrated acid. Appropriate employee training, use of 

adequate PPE, and routine maintenance of equipment should 

help reduce the likelihood that such events will occur, and also 

Conclusion
Page 10 Health Hazard Evaluation Report 2006-0298-3090

Discussio  (continu

Recommendatio

reduce the risk of employee illness or injury if a spill or leak does 

occur. Ventilation in the Steris room appears to be insufficient 

for providing reliable odor control and maintaining the work 

environment within an acceptable range of temperature and RH.

The following recommendations are provided to improve the safety 

and health of hospital staff that clean and sterilize endoscopes at in 

the A2 GI Lab Steris Room.

Training

● Conduct and document hazard communication training 

required by the OSHA Hazard Communication Standard 

(29 CFR 1910.1200). Training should be provided for new 

and current employees, and should be designed specifically 

for A2 GI Lab Steris Room workers. Training should 

address chemical hazards, exposure controls, and PPE for all 

chemicals used to process endoscopes, including Steris 20 

Sterilant Concentrate, Klenzyme Concentrate Plus Enzymatic 

Cleaner and Cidex OPA Solution.

● Conduct training for Steris room employees that addresses 

standard operating procedures in the event of chemical 

spills, processor malfunctions, and processor leaks. Training 

should include notification procedures for contacting 

Environmental Services for spill cleanup.

● Contact Steris Corporation to request new employee initial 

and annual refresher inservice training for SS1 processor 

operators. Training should include routine and nonroutine 

processor operations, handling of unopened sterilant cups, 

and disposal of incompletely aspirated and expired cups. 

Annual refresher training would allow a Steris representative 

to review technicians’ technique, and to provide instructions 

for the proper use and handling of Steris 20 Sterilant 

Concentrate.

Personal Protective Equipment

● Given the serious nature of injuries that may result from 

exposure to Steris 20 Sterilant Concentrate, appropriate PPE 

should be worn by workers when handling both sealed and 

used containers of Steris 20 Sterilant Concentrate.
Health Hazard Evaluation Report 2006-0298-3090 Page 11

Recommendatio

(continued) ● Minimum PPE worn while performing routine tasks

involving the handling of sealed Steris cups should include 

tight-fitting splash-resistant goggles, acid-resistant sleeves 

and apron, and gloves made of butyl rubber, neoprene 

rubber, Viton®, or Barrier® [Forsberg and Mansdorf 2007]. 

Very thin gloves, as typically worn in healthcare settings, 

provide poor chemical resistance and mechanical strength, 

and should not be the only barrier between the wearer and 

a chemical hazard, such as PAA [Forsberg and Mansdorf 

2007]. Latex gloves do not provide appropriate protection 

and introduce a known allergen into the workplace [NIOSH 

1997].

● If sterilant remains in a cup at the end of a sterilization 

cycle, the technician should don additional face protection 

(e.g., face shield in addition to gloves, sleeves, apron, and 

eye protection used during normal operations). This PPE 

should be worn when handling unsealed cups containing 

any sterilant concentrate, and when disposing of expired 

sterilant.

Preventive Maintenance and Equipment 

Malfunctions

● SS1 processors should be inspected periodically for 

components that can fail due to normal wear, resulting in a 

leak or worker exposure. These components include aspirator 

tubing, processor lid seal, and endoscope trays.

● Employees should notify management of all spills, leaks, 

and equipment malfunctions so that the causes of these 

events can be identified and appropriate corrective actions 

can be taken. BGH should notify Steris Corporation of 

equipment malfunctions and request assistance from Steris 

in diagnosing and correcting problems.

Ventilation and Indoor Environmental 

Quality

● The Steris room must be under negative pressure relative to 

all surrounding areas in order to control odors. The HVAC 

system serving the Steris room should exhaust completely 

to the outdoors, i.e., no recirculation. The dirty side should 

be under negative pressure relative to the clean side to help 

prevent migration of bioaerosols from the dirty side to the 

clean side.
Page 12 Health Hazard Evaluation Report 2006-0298-3090

Recommendatio

(continued

Referenc

● A minimum of 10 air changes per hour should be provided 

in the Steris room, with a minimum of 2 air changes 

of outside air per hour [ASHRAE 2003; ACGIH 2007; 

ASHRAE 2007].

● Supply diffusers and return grilles need to be located so that 

supply air reaches room occupants without “short circuiting,” 

i.e., flowing directly from supply diffusers to return ducts 

without ventilating the occupied space.

● ASHRAE recommends maintaining sterilizer equipment 

rooms between 72oF and 76oF, with RH between 30% and 

60% [ASHRAE 2007].

● Ensure that the GUS Vapor Control System is operating 

whenever it contains OPA, and that the charcoal filters are 

changed every 6 months or as advised by PCI Medical, Inc 

[PCI 2009].

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

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

of Governmental Industrial Hygienists.

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.

Advanced Sterilization Products [2007]. Material safety data sheet, 

CIDEX® OPA solution. MSDS-09588-0-001, Rev. F. Irvine, CA: 

Advance Sterilization Products. [www.sterrad.com/Customer_

Support/user_resources/msds/cidexopa_msds.pdf]. Date accessed: 

March 30, 2009.

Alfa MJ [2004]. SYSTEM 1® Sterile Processing System: liquid 

chemical sterilization anthology. [www.steris.com]. Date accessed: 

March 23, 2009.

ASHRAE [2003]. HVAC design manual for hospitals and clinics. 

Atlanta, GA: American Society of Heating, Refrigerating, and AirConditioning Engineers, Inc.

ASHRAE [2007]. The ASHRAE handbook—HVAC applications. 

Atlanta, GA: American Society of Heating, Refrigerating, and AirConditioning Engineers, Inc.
Health Hazard Evaluation Report 2006-0298-3090 Page 13

Reference  (continued) Draeger [2009]. Short-term measurements with Dräger-Tube

[www.draeger.com]. Date accessed: March 14, 2009.

Forsberg K, Mansdorf SZ [2007]. Quick selection guide to chemical 

protective clothing. 5th ed. Hoboken, NJ: John Wiley & Sons, Inc.

Fujita H, Ogawa M, Endo YA [2006]. A case of occupational 

bronchial asthma and contact dermatitis caused by orthophthalaldehyde exposure in a medical worker. J Occup Health 

48(6): 413–416.

Hathaway GJ, Proctor NH, Hughes JP [1996]. Chemical hazards of 

the workplace. 4th ed. New York, NY: Van Nostrand Reinhold.

IPCS [1994a]. International chemical safety cards, peracetic acid 

(stabilized). ISCS no. 1031, partial update April 2005. Geneva, 

Switzerland: World Health Organization, International Programme 

on Chemical Safety. [www.cdc.gov/niosh/ipcsneng/neng1031.

html]. Date accessed: July 23, 2009.

IPCS [1994b]. International chemical safety cards, acetic acid. 

ISCS no. 0363, partial update October 2005. Geneva, Switzerland: 

World Health Organization, International Programme on 

Chemical Safety. [www.cdc.gov/niosh/ipcsneng/neng0363.html]. 

Date accessed: July 23, 2009.

Neumeister CE [2009]. E-mail communication from C. 

Neumeister, Division of Applied Research and Technology, 

National Institute for Occupational Safety and Health, Centers for 

Disease Control, U.S. Department of Health and Human Services 

to D. Sylvain. February 3, 2009.

NIOSH [1992]. Recommendations for occupational safety and 

health: compendium of policy documents and statements. 

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

Centers for Disease Control, National Institute for Occupational 

Safety and Health, DHHS (NIOSH) Publication No. 92-100.

NIOSH [1997]. Preventing allergic reactions to natural rubber latex 

in the workplace. Cincinnati, OH: U.S. Department of Health and 

Human Services, Centers for Disease Control, National Institute 

for Occupational Safety and Health, DHHS (NIOSH) Publication 

No. 97-135.

NJDHSS [1998a]. Hazardous substance fact sheet, peroxyacetic 

acid. RTK substance no. 1482, revised October 2004. Trenton, NJ: 
Page 14 Health Hazard Evaluation Report 2006-0298-3090

Reference  (continued) New Jersey Department of Health and Senior Service

[http://nj.gov/health/eoh/rtkweb/documents/fs/1482.pdf]. Date 

accessed: March 14, 2009.

NJDHSS [1998b]. Hazardous substance fact sheet, acetic acid. RTK 

substance no. 0004, revised July 2007. Trenton, NJ: New Jersey 

Department of Health and Senior Services. 

[nj.gov/health/eoh/rtkweb/documents/fs/0004.pdf]. Date 

accessed: March 14, 2009.

PCI [2009]. GUS® vapor control systems for OPA and 

glutaraldehyde, frequently asked questions. Deep River, CT: PCI 

Medical. [www.pcimedical.com]. Date accessed: March 25, 2009.

Sciencelab.com [2005]. Material safety data sheet, peracetic acid, 

35%, updated November 11, 2008. Houston, TX: Sciencelab.com, 

Inc. [www.sciencelab.com]. Date accessed: March 30, 2009.

Steris [1995]. Product safety data sheet, Steris 20® Sterilant 

Concentrate. MSDS No. 612038, revised January 21, 2009. 

Mentor, OH: Steris Corporation. [www.steris.com]. Date accessed: 

March 26, 2009.

Steris [2007]. SYSTEM 1® Sterile Processing System in-service 

checklist. Document ST1006EN.2007-07, August 2007. [www.

steris.com/]. Date accessed: March 26, 2009.

Steris [2008]. SYSTEM 1® Sterile Processing System technical data 

document SD707, revised June 1, 2008 [www.steris.com]. Date 

accessed: March 30, 2009.

Tripathi A, Grammer LC [2001]. Extrinsic allergic alveolitis from a 

proteolytic enzyme. Ann Allergy Asthma Immunol 86(4):425–427.

USFDA [2009]. Adverse event reporting data files. Center 

for Devices and Radiological Health, U.S. Food and Drug 

Administration, Department of Health and Human Services. 

[www.fda.gov/cdrh/mdr/mdr-file-general.html]. Date accessed: 

March 24, 2009.
Health Hazard Evaluation Report 2006-0298-3090 Page 15

Acknowledgments a

Availability of Rep

The Hazard Evaluation 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 (OSHA) 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 David Sylvain and John Gibbins of 

HETAB, Division of Surveillance, Hazard Evaluations and Field 

Studies. Analytical support was provided by Charles Neumeister 

of the Division of Applied Research and Technology. 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 Kaleida Health-Buffalo General Hospital, the 

state health department, and the OSHA 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 worker exposures 

to peracetic acid-based sterilant during endoscope reprocessing, Buffalo, NY. 

By Sylvain D, Gibbins J. 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. 2006-0298-3090.

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