U.S. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD

SUMMARY REPORT

NITROGEN ASPHYXIATION

(1 DEATH, 1 INJURY)

 UNION CARBIDE CORPORATION

 Hahnville, Louisiana

 March 27, 1998

KEY ISSUES:

• USE OF NITROGEN IN CONFINED SPACES

• SAFETY OF TEMPORARY ENCLOSURES

REPORT NO. 98-05-I-LA
1

Abstract: This summary report explains an incident that occurred March 27, 1998, at Union

Carbide Corporation’s Taft/Star Manufacturing Plant in Hahnville, Louisiana. One Union Carbide

worker was killed and an independent contractor was seriously injured due to nitrogen asphyxiation. 

Safety issues discussed in this report include the hazards of temporary enclosures and the use of

nitrogen when working in confined spaces. Recommendations concerning these issues were made to

Union Carbide Corporation, the Occupational Safety and Health Administration, and others. This

summary report also contains a recommendation to the National Institute for Occupational Safety and

Health that it conduct a study concerning the feasibility of odorizing nitrogen when it is used in

confined spaces. 

The Chemical Safety and Hazard Investigation Board (CSB) is an independent federal agency

whose mission is to ensure the safety of workers and the public by preventing or minimizing the

effects of chemical incidents at industrial facilities. The CSB is a scientific investigatory

organization; it is not an enforcement or regulatory body. Established by the Clean Air Act

Amendments of 1990, the CSB is responsible for determining the probable causes of incidents,

issuing safety recommendations, studying chemical safety issues, and evaluating the effectiveness

of other government agencies involved with industrial chemical safety. Section 112(r)(6)(G) of the

Clean Air Act prohibits the use of any conclusions, findings, or recommendations of the CSB

relating to any chemical incident from being admitted as evidence or used in any lawsuit arising out

of any matter mentioned in an investigation report. The CSB makes public its actions and

decisions through investigation reports, summary reports, safety studies, safety recommendations,

special technical publications, and statistical reviews. A summary report addresses incidents that

are within the CSB’s jurisdiction, but because of the limited nature of the issues involved, do not

require a more comprehensive investigation and report. More information about the CSB may be

found on the World Wide Web (http://www.chemsafety.gov).

Information about CSB publications may be obtained by contacting:

Chemical Safety and Hazard Investigation Board

Office of External Relations

2175 K Street, N.W. -- Suite 400

Washington, D.C. 20037

(202) 261-7600

CSB publications may be purchased from:

National Technical Information Service

5285 Port Royal Road

Springfield, Virginia 22161

(703) 487-4600

Salus Populi Est Lex Suprema

People’s Safety is the Highest Law
2

TABLE OF CONTENTS

1.0 INTRODUCTION ............................................................................................................... 4

1.1 BACKGROUND ............................................................................................................. 5

1.2 EVENTS PRECEDING THE INCIDENT...................................................................... 6

1.3 THE INCIDENT.............................................................................................................. 9

2.0 ANALYSIS OF THE INCIDENT..................................................................................... 11

2.1 CONFINED SPACE HAZARD.................................................................................... 11

2.2 CONTROL OF SECONDARY HAZARDS................................................................. 13

2.3 HISTORY OF NITROGEN-RELATED FATALITIES IN CONFINED SPACES...... 14

2.4 NITROGEN WARNING MEASURES ........................................................................ 15

3.0 ROOT AND CONTRIBUTING CAUSES....................................................................... 17

4.0 RECOMMENDATIONS................................................................................................... 18

5.0 REFERENCES................................................................................................................. 20

APPENDIX A: List of Other Nitrogen Asphyxiation Cases .......................................... 21

APPENDIX B: Material Safety Data Sheet for Nitrogen ................................................ 22
3

TABLE OF FIGURES

FIGURE 1. MAJOR EQUIPMENT OF THE TAFT OXIDE UNIT I ...................................6

FIGURE 2. CLEAR PLASTIC SHEET COVERING ONE OF THE PIPE OPENINGS .........7

FIGURE 3. THE FLANGE ON THE NORTH END OF THE PIPE....................................8
4

1.0 INTRODUCTION

The United States Chemical Safety and Hazard Investigation Board (CSB) is an independent

federal agency whose mission is to improve the safety of workers and the public by preventing

chemical incidents. One of the CSB’s duties is to conduct investigations of serious incidents to

identify the causes and recommend changes to prevent recurrence.

On March 27, 1998, at approximately 12:15 pm, two workers at Union Carbide Corporation’s

Taft/Star Manufacturing Plant (the plant) in Hahnville, Louisiana, were overcome by nitrogen gas

while performing a black light inspection1 at an open end of a 48-inch-wide horizontal pipe. The

48-inch pipe was open because chemical-processing equipment had been shut down and opened

for major maintenance. Nitrogen was being injected into the process equipment primarily to

protect new catalyst in reactors from exposure to moisture. The nitrogen was also flowing

through some of the piping systems connected to the reactors. The nitrogen was venting from one

side of the open pipe where it had formerly been connected to an oxygen feed mixer. No warning

sign was posted on the pipe opening identifying it as a confined space or warning that the pipe

contained potentially hazardous nitrogen. 

The two workers had placed a sheet of black plastic over the end of the pipe to provide shade to

make it easier to conduct the black light test during daylight. While working just outside the pipe

opening and inside of the black plastic sheet, the two workers were overcome by nitrogen. One

worker died from asphyxiation. The other worker survived but was severely injured.

Nitrogen is an odorless, tasteless, and invisible gas that can cause asphyxiation at high

concentrations. When used in confined spaces, nitrogen is especially hazardous because it cannot

be detected by human senses but can cause injury or death within minutes by displacing the oxygen

that is required to sustain life.

 

1 A black light was used to see any residue of organic material, such as grease or oil, on the pipe. Organic residue shines

when viewed under a black light.
5

1.1 BACKGROUND

The plant, which produces chemicals for industry, is located about 30 miles west of New Orleans

and employs approximately 1,130 people. The incident occurred in the plant’s Taft Oxide I Unit

(the Unit). The Unit primarily produces ethylene oxide, ethylene glycol, and glycol ethers. (See

Figure 1 for the numbered locations of the major equipment involved in the Unit’s process.) The

Unit uses ethylene and methane as feed gases to produce ethylene oxide. Ethylene and methane

are mixed with oxygen (see Figure 1, item 4) and then put in contact with a catalyst located in the

reactors (see Figure 1, item 1). A scrubber removes the product while carbon dioxide gas is also

removed. The incident occurred at the fifth level of the structure, approximately 60 feet above the

ground.

Various plant operations are periodically shut down for a “turnaround.” A turnaround is an

industry term describing the time when major maintenance and inspection of process equipment

takes place. At the time of the incident, the Unit had been in a turnaround status for about six

weeks.

The worker injured in the incident (Worker A) was retained as an independent contractor and was

in charge of daily operations in the reaction area during the turnaround. He had retired from

Union Carbide after 32 years of service, primarily at the plant. His last position prior to retirement

was Reaction Area Specialist for the same Unit.

The worker who died (Worker B) was a Union Carbide employee who had 23 years of service at

the plant. He was a Maintenance Skilled Operations Team Technician in the Unit. Worker B was

under the general direction of Worker A at the time of the incident. 
6

2

OXIDE I REACTION CYCLE SYSTEM

EO

SCRUB

Oxide

HX

Reactors

Cycle

C

Y

C

L

E

G

A

S

C

L

R

CYCLE

COMPRESSOR

Gas

E

N

T

S

E

P

METHANE

N S

EDC FEED

ETHYLENE FEED

48"

CO2

ABSORBER

VENT

N2

HOSE

48"

N2

HOSE

(CLOSED)

Oxide

Reactors

VENT

N2

HOSE

4 BYPASSES WIDE

OPEN, 1 PARTIALLY

OPEN, 4 CLOSED

48"

1 REACTORS, WHICH CONTAIN CATALYST

3

NITROGEN SUPPLY

4 LOCATION OF OXYGEN FEED MIXER WHEN INSTALLED

5 CO2 REMOVAL SYSTEM

6 SOUTH FLANGE

7 NORTH FLANGE

1

2

3

3

4

5

7 6

BYPASSES AROUND VALVES,

WHICH WHEN OPEN ALLOW N2 TO FLOW

TO PROCESS PIPING

2

Figure 1. Major Equipment of the Taft Oxide Unit I

1.2 EVENTS PRECEDING THE INCIDENT

Two primary maintenance activities were scheduled during the turnaround of the Unit: replacement

of the old catalyst in the reactors with new catalyst and cleaning the oxygen feed mixer (see Figure

1, items 1 and 4). The oxygen feed mixer had been removed from the piping system for cleaning. 

Removing the oxygen feed mixer exposed two open ends on 48-inch piping that had been

Location of Incident
7

connected to the oxygen feed mixer. The two open pipe ends were wrapped with a clear plastic

sheet in order to keep the pipe free of debris until the oxygen feed mixer was reinstalled. Figure 2

shows the clear plastic sheet over one of the 48-inch pipe openings and the black plastic sheet lying

near the opening. 

Figure 2. Clear Plastic Sheet Covering One Of The Pipe Openings

The oxygen feed mixer needed to be free of grease, oil, or other organic chemicals because these

materials are incompatible with the chemical process that takes place in the oxygen feed mixer. 

Workers used a cleaning solution containing ethylene trichloride to remove these materials. Later,
8

workers used a black light to check for any residual deposits of organic chemicals, because the

deposits would be seen more clearly under the black light. The parts of the pipe that the workers

examined with the black light were the two flange surfaces, which were located at the ends of the

pipe that connected to the oxygen feed mixer. Figure 3 shows the north end of the pipe and the

flange surface. Although a black light inspection was a typical part of oxygen feed mixer cleaning,

it was not needed on the 48-inch pipe flange surfaces. For these flanges, a visual inspection was all

that was required. The CSB investigation did not discover any conclusive reason that explained

why Workers A and B decided to perform black light inspections on the pipe flanges.

Figure 3. The Flange on the North End of the Pipe
9

The catalyst used in the ethylene oxide reactors was sensitive to moisture.2 Therefore, following

replacement of the old catalyst, the new catalyst was protected from exposure to moisturecontaining air by injecting nitrogen gas into the area around the catalyst. The nitrogen displaced the

air in the reactors and blanketed the catalyst.

The evening before the incident, Worker A directed Operations Technicians to add the nitrogen to

the piping because the catalyst had been changed. Because nitrogen would retard rust formation in

the piping connected to the reactors, two valves (see Figure 1, item 2) were opened to allow the

flow of nitrogen into the process piping. The nitrogen vented from the open end of the 48-inch pipe

(see Figure 1, item 7) on the north side of where the pipe formerly connected to the oxygen feed

mixer.

1.3 THE INCIDENT

On the day of the incident, Workers A and B performed a black light inspection and cleaning of the

two flange surfaces on the open 48-inch pipe, beginning with the south flange (see Figure 1, item

6). Because the midday sun made it difficult to see any grease or oil residues with the black light,

Workers A and B used a sheet of black plastic to provide a darker working area. The black plastic

sheet was fastened over the pipe flange because there was a strong breeze that day. The plastic

sheet was held in place by Workers A and B sitting on one edge of the sheet with the remainder of

the sheet held over them and against the exterior of the pipe flange by two contractor workers. 

The contractor workers were in the area because they were waiting for the oxygen feed mixer to

be lifted back into place. Though unintended, the plastic sheet created a temporary enclosure

around Workers A and B. The inspection and cleaning of the south pipe flange began at

approximately 10:45 am and was completed at about 11:35 am. There was no incident because

 

2 The specific catalyst used is proprietary information, and it is not necessary to reveal its name for the purposes of this

report.
10

the nitrogen was not venting through the south pipe opening. The south pipe was also connected

to the reactors, but a closed valve blocked this piping, thus preventing the flow of nitrogen to the

south pipe.

Next, the workers and the contractors placed a plastic sheet in the same fashion on the north pipe

flange while Workers A and B conducted an inspection and cleaning. Because this part of the pipe

was being purged with nitrogen, it contained a high level of nitrogen. The temporary plastic

enclosure trapped a high concentration of the nitrogen, which continued to vent out of the north

pipe. Worker A probably did not realize that nitrogen was venting from the pipe even though the

evening before he had directed that nitrogen be injected into the piping system. He may have not

remembered that nitrogen was in the pipe because the nitrogen was injected at a distant location,

150 feet and several stories in elevation away from the site of the incident.

Contractors, who were on the other side of the black plastic sheet, reported talking with Workers

A and B. The last communication with Workers A and B took place just after noon. At

approximately 12:20 pm, a contractor noticed blood on one of the worker’s hands when he looked

through a gap in the plastic sheet. He alerted his foreman. The foreman called to the two workers

behind the sheet and, getting no reply, removed the sheet. Worker B was found in front of the

pipe, unconscious and slumped over with his head lying inside the open pipe. Witnesses said that

his skin color was purple. Worker A was found seated beside the pipe opening, dazed and leaning

against the side of the pipe. His color was described as white.

Emergency assistance was requested. The plant emergency response team arrived and removed

the two men from the Unit while administering cardiopulmonary resuscitation to Worker B. The

two workers were transported by ambulance to St. Charles Parish Hospital. Worker B was dead

on arrival. Worker A was admitted to the hospital in critical condition and given oxygen therapy

over the next several days. He was released after five days in the hospital.
11

2.0 ANALYSIS OF THE INCIDENT

2.1 CONFINED SPACE HAZARD

In 1993, the Occupational Safety and Health Administration (OSHA) confined space entry

standard3 became effective. OSHA defines a confined space as a space that is large enough to

enter, has limited or restricted means for entry or exit, and has not been designed for continuous

human occupancy. The open pipe involved in the incident may have fit the OSHA definition of a

confined space. The temporary enclosure involved in this incident may not have been considered

to have a limited or restricted means of exit and, therefore, may not necessarily be considered to be

a confined space. In this incident, however, OSHA did cite Union Carbide for violation of the

standard.

OSHA defines a permit-required confined space as one that meets all of the above criteria and also

contains or has the potential to contain a hazardous atmosphere. In order to enter a permitrequired confined space, OSHA requires that personnel monitor the atmosphere in the space and

that the company issue a written permit that identifies the hazards present and the precautions that

must be taken before entry. Although OSHA may not always consider temporary enclosures that

have easy means of exit, such as the one involved in this incident, to be confined spaces, the use of

permit-required confined space entry procedures for the temporary enclosure at the plant likely

would have prevented this incident.

One factor that makes entering a confined space hazardous is that the space may contain a

hazardous atmosphere. A confined space may contain a toxic gas, such as hydrogen sulfide, in

concentrations hazardous to health. Other confined spaces may contain a nontoxic gas, such as

nitrogen, in concentrations that displace the oxygen in the air in the space. The air we normally

 

3 See 29 CFR § 1910.146.
12

breathe contains about 21% oxygen, 78% nitrogen, and trace amounts of other gases. In this

incident, the nitrogen acted as an asphyxiant, causing suffocation by displacing oxygen-containing

air.

It is not necessary for nitrogen to displace all of the 21% of oxygen normally found in the air in

order to cause harm to people. OSHA requires that oxygen levels be maintained at or above

19.5% in order to prevent injury to workers. According to the Compressed Gas Association,

“exposure to atmospheres containing 8-10 percent or less oxygen will bring about unconsciousness

without warning and so quickly that the individuals cannot help or protect themselves.”4 Exposure

to an atmosphere containing 6-8 percent oxygen can be fatal in as little as 6 minutes. Exposure to

an atmosphere containing 4-6 percent oxygen can result in a coma in 40 seconds and subsequent

death.

In this incident, no signs were posted at the pipe opening to warn workers and contractors that it

was a confined space or that it contained nitrogen. Even if the temporary enclosure had not been

erected around the north pipe opening, an employee or a contractor could have been overcome by

nitrogen if he or she merely had inserted his or her head into the pipe for a short time. A worker or

a contractor could have put his head into the north pipe opening as part of cleaning or inspecting

the pipe flange. OSHA has investigated confined space injuries and fatalities at other facilities in

which a worker only entered a confined space with his head.

Prior to the incident, the plant’s safety program did not adequately address the control of hazards

associated with the creation of temporary enclosures around chemical plant equipment. For

example, temporary enclosures that had an easy means of exit were generally not covered by the

safety requirements of the plant’s confined space entry policy. After the incident, the plant

manager issued a safety notice alerting employees about the incident and banned, pending further

review, all inspections of equipment in process units that required a cover or similar method to

exclude light. The safety notice was communicated to Union Carbide facilities worldwide. Also,

 

4 Compressed Gas Association; Safety Bulletin SB-2 (1992).
13

Union Carbide conducted additional training on nitrogen safety.

2.2 CONTROL OF SECONDARY HAZARDS

It is important that safety management efforts look beyond the immediate task to anticipate

secondary hazards. The open pipe was an unrecognized secondary hazard in the oxygen feed

mixer cleaning activity. There was no evaluation of the impact of the catalyst change activity and

nitrogen purge on the seemingly unrelated oxygen feed mixer cleaning activity. Management

should have performed this type of evaluation when it planned to inject nitrogen into the 48-inch

pipe and out of the north end of the pipe. Such an evaluation could have revealed the risk to

workers from nitrogen in the pipe. Recognition of the nitrogen hazard could have identified the

need to post a nitrogen warning sign at the pipe opening where the incident took place.

Interviews with members of the plant management revealed that they did not expect anyone to

perform a black light inspection of the pipe flanges. Management personnel said it was

unnecessary to clean the flanges because the oxygen feed mixer had been cleaned and an enriched

oxygen atmosphere would not contact the flanges.

Although management did not expect the specific job of a black light inspection to be performed,

there were other workers in the area who needed to be protected from the potential nitrogen

hazard. Earlier during the day of the incident, contractor employees used wire brushes and

cleaning solution to clean the same 48-inch pipe flanges that were later inspected with the black

light. In order to perform this job, contractors removed the clear plastic sheets covering the pipe

openings, thereby exposing themselves to the nitrogen hazard. Because there was a strong breeze

that day, the nitrogen venting from the north end of the pipe was quickly dissipated and did not

harm the contractors.
14

2.3 HISTORY OF NITROGEN-RELATED FATALITIES IN CONFINED SPACES

According to OSHA’s records, at least 21 people died in the U.S. between 1990 and early 1996 in

incidents involving the use of nitrogen in confined spaces. The OSHA confined space entry

standard required facilities covered by the law, including the Taft plant, to fully implement its

requirements by April 15, 1993. Currently available OSHA fatality data shows that the number of

reported fatal incidents involving nitrogen remained about the same in the three-year period

following issuance of the confined space entry standard as in the three years preceding issuance of

the standard. Nine nitrogen-related incidents resulted in 12 fatalities during the 3-year period

preceding issuance of the OSHA confined space entry standard. An additional nine nitrogenrelated incidents resulted in nine fatalities during the 3-year period that followed issuance of the

standard.5 Appendix A contains further information on these fatalities. 

This fatality data does not take into account the possible increased use in recent years of nitrogen

in confined spaces. (Thus, even though the data shows that the number of fatalities has remained

fairly constant, if industry used nitrogen more frequently in later years, the rate of fatalities may

have actually declined.) Therefore, this data by itself should not be interpreted to mean that there

has been no decline in the fatality rate trend. Nonetheless, the OSHA fatality data indicates that

the use of nitrogen in confined spaces remains a hazard to workers. 

In this incident, the plant had a confined space entry program and a chemical safety-training

program. Nonetheless, one very experienced worker died and another was seriously injured

because these workers were not aware that they were being exposed to dangerous levels of

nitrogen. 

 

5 OSHA notes that its statistics may be incomplete. Additional incidents may have taken place which are not reflected in

OSHA’s data. In addition, data from earlier years may omit fatality reports from some states that administer their own

worker safety programs.
15

This potentially dangerous substance cannot be detected by the human senses. In addition, high

concentrations of nitrogen are dangerous because personnel may not recognize physical or mental

symptoms resulting from over-exposure. The two workers involved in the incident were unable to

recognize that they were in trouble. They did not try to leave the hazardous work area even

though there was an easy means of escape. Also, contractors were located nearby, but the two

workers did not ask for help.

2.4 NITROGEN WARNING MEASURES

Like natural gas and propane (two other potentially hazardous gases), nitrogen does not have a

naturally occurring odor that can adequately warn people of its presence. Odorant is added to

natural gas and propane as a safety measure to provide a warning that a leak has occurred or that

the flammable and explosive gas is present. 

Odorant is not normally added to nitrogen because a release of nitrogen is not typically a

hazardous event. Nitrogen is nontoxic and will not ignite or react with other substances, but it can

be very hazardous when used in confined spaces that workers enter. It displaces the oxygen in the

space, and at high concentrations, it can cause death. A Material Safety Data Sheet for nitrogen is

included in Appendix B.

Posting warning signs to alert personnel of confined space and nitrogen hazards is a useful safety

measure. Personnel may occasionally forget to post warning signs or the signs may be accidentally

removed, however. If the nitrogen used to purge the reactors at the Taft plant had contained an

odorant, the personnel would have been alerted that the gas was present and the incident would

have been prevented. 

Odorization of nitrogen that is used in confined spaces should not be viewed as a substitute for

existing confined space entry safety measures; it would be an additional precaution.
16

The CSB is aware that technical issues, such as the possible contamination of certain catalysts by

the use of an odorant in nitrogen, must be studied. Therefore, research is needed concerning the

feasibility of odorizing nitrogen that is used in confined space applications.
17

3.0 ROOT AND CONTRIBUTING CAUSES

Root Causes

1. Procedures to control potential hazards created by erecting temporary enclosures

around nitrogen-containing equipment were inadequate.

The plant did not have adequate procedures in place to address potential hazards created by

the use of temporary enclosures. Temporary enclosures erected around tanks, vessels,

pipes, or similar equipment that contain hazardous material may trap a dangerous

atmosphere if the equipment leaks or vents substances, such as nitrogen, into the enclosure.

2. Nitrogen and confined space hazard warnings were inadequate.

Personnel were not aware of the hazard of the nitrogen flowing out of the open pipe that

they were working on, even though one of injured individuals had earlier directed that

nitrogen be injected into the equipment. No warning signs were posted identifying the pipe

as a confined space or alerting personnel to the presence of nitrogen.

Contributing Cause

Personnel were unable to detect hazardous levels of nitrogen because this gas cannot

be detected by human senses.

Odorization of nitrogen could have warned personnel that a hazardous atmosphere was

present and thereby prevented the incident.
18

4.0 RECOMMENDATIONS

Union Carbide Taft Plant

1. Post signs containing the warning “Danger, Confined Space: Do Not Enter Without

Authorization” or similar wording at potential entryways when tanks, vessels, pipes, or

other similar chemical industry equipment are opened. When nitrogen is added to a

confined space, post an additional sign that warns personnel of the potential nitrogen

hazard. (98-05-I-LA-R1)

2. Ensure that the plant safety program addresses the control of hazards created by erecting

temporary enclosures around equipment that may trap a dangerous atmosphere in the

enclosure if the equipment leaks or vents hazardous material. (98-05-I-LA-R2)

National Institute for Occupational Safety and Health

Conduct a study concerning the appropriateness and feasibility of odorizing nitrogen in

order to warn personnel of the presence of nitrogen when it is used in confined spaces. 

(98-05-I-LA-R3)

Occupational Safety and Health Administration

Issue a safety alert that addresses the hazards and provides safety guidelines for the use of

temporary enclosures that are erected around equipment containing hazardous substances. 

(98-05-I-LA-R4)
19

Center for Chemical Process Safety

Communicate the findings of this report to your membership. (98-05-I-LA-R5)

Compressed Gas Association

Communicate the findings of this report to your membership. (98-05-I-LA-R6)

BY THE CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD

Paul L. Hill, Jr.

Chairman

Gerald V. Poje

Member

Andrea Kidd Taylor

Member

Isadore Rosenthal

Member

February 23, 1999
20

5.0 REFERENCES

Compressed Gas Association; Safety Bulletin SB-2 (1992).

Occupational Safety and Health Administration; Confined Space Entry Standard, 29 CFR §

1910.146 (1998).

Union Carbide Corporation/Taft Plant HS & EA Policy Manual (May 1996).

Union Carbide Corporation/Taft Plant Responsible Care Policies Manual (December 1997).
21

APPENDIX A: List of Other Nitrogen Asphyxiation Cases

The following data is based on publicly available OSHA statistics concerning fatalities in confined

spaces due to nitrogen exposure.

Date OSHA Began Inspection Fatalities OSHA Accident Number

07-16-1990 1 170228431

10-17-1990 1 014514616

04-15-1991 1 014449839

06-14-1991 1 000686261

07-30-1991 1 014414080

04-30-1992 3 000767681

05-18-1992 1 000829234

06-04-1992 2 014322119

11-02-1992 1 000912576

The OSHA Confined Space Entry Standard became effective on April 15, 1993.

Date OSHA Began Inspection Fatalities OSHA Accident Number

10-20-1993 1 014495154

01-28-1994 1 170374607

09-24-1994 1 000820407

12-27-1994 1 001000942

01-17-1995 1 170681746

06-12-1995 1 170060917

06-26-1995 1 000552430

10-25-1995 1 000906578

01-31-1996 1 170903405
22

APPENDIX B: Material Safety Data Sheet for Nitrogen

 

1

0

HEALTH 0

FLAMMABILITY

REACTIVITY

OTHER

NFPA RATING

3

0

HEALTH 0

FLAMMABILITY

REACTIVITY

OTHER

NFPA RATING

 

Prepared to U.S. OSHA, CMA, ANSI and Canadian WHMIS Standards

PART I What is the material and what do I need to know in an emergency?

1. PRODUCT IDENTIFICATION

CHEMICAL NAME; CLASS: NITROGEN - N2

LIQUEFIED NITROGEN N2,

(Cryogenic)

Document Number: 1040

PRODUCT USE: For general analytical/synthetic chemical uses.

SUPPLIER/MANUFACTURER'S NAME: AIRGAS INC.

ADDRESS: 259 Radnor-Chester Road

Suite 100

Radnor, PA 19087-5240

BUSINESS PHONE: 1-610-687-5253

EMERGENCY PHONE: CHEMTREC: 1-800-424-9300

International: 202-483-7616

DATE OF PREPARATION: May 12, 1996

SECOND REVISION : December 11, 1997

2. COMPOSITION and INFORMATION ON INGREDIENTS

CHEMICAL NAME CAS # mole % EXPOSURE LIMITS IN AIR

ACGIH OSHA

TLV STEL PEL STEL IDLH OTHER

ppm ppm ppm ppm ppm

Nitrogen 7727-37-9 99.995 % There are no specific exposure limits for Nitrogen. Nitrogen is a simple asphyxiant (SA). Oxygen levels should be

maintained above 19.5%.

Maximum Impurities <0.1

(50 ppm)

None of the trace impurities in this mixture contribute significantly to the hazards associated with the product. All

hazard information pertinent to this product has been provided in this Material Safety Data Sheet, per the

requirements of the OSHA Hazard Communication Standard (29 CFR 1910.1200) and State equivalents standards.

NE = Not Established C = Ceiling Limit See Section 16 for Definitions of Terms Used

NOTE: all WHMIS required information is included. It is located in appropriate sections based on the ANSI Z400.1-1993 format.

MATERIAL

SAFETY

DATA SHEET

NITROGEN GAS LIQUID NITROGEN
23

3. HAZARD IDENTIFICATION

EMERGENCY OVERVIEW: Nitrogen is a colorless, odorless, non-flammable gas, or a colorless, odorless,

cryogenic liquid. The main health hazard associated with releases of this gas is asphyxiation, by displacement of oxygen.

 The cryogenic liquid will rapidly boil to the gas at standard temperatures and pressures. The liquefied gas can cause

frostbite to any contaminated tissue.

See Section 16 for

Definition of Ratings

SYMPTOMS OF OVEREXPOSURE BY ROUTE OF EXPOSURE: The most significant route of overexposure for this

gas is by inhalation. The following paragraphs describe symptoms of exposure by route of exposure.

INHALATION: High concentrations of this gas can cause an oxygen-deficient environment. Individuals breathing

such an atmosphere may experience symptoms which include headaches, ringing in ears, dizziness, drowsiness,

unconsciousness, nausea, vomiting, and depression of all the senses. The skin of a victim may have a blue color.

 Under some circumstances, death may occur. The effects associated with various levels of oxygen are as follows:

CONCENTRATION SYMPTOMS OF EXPOSURE

12-16% Oxygen: Breathing and pulse rate increased, muscular coordination slightly disturbed.

10-14% Oxygen: Emotional upset, abnormal fatigue, disturbed respiration.

6-10% Oxygen: Nausea and vomiting, collapse or loss of consciousness.

Below 6%: Convulsive movements, possible respiratory collapse, and death.

OTHER POTENTIAL HEALTH EFFECTS: Contact with cryogenic liquid or rapidly expanding gases (which are

released under high pressure) may cause frostbite. Symptoms of frostbite include change in skin color to white or

grayish-yellow. The pain after contact with liquid can quickly subside.

HEALTH EFFECTS OR RISKS FROM EXPOSURE: An Explanation in Lay Terms. Overexposure to Nitrogen may

cause the following health effects:

NITROGEN GAS LIQUID NITROGEN

HEALTH

FLAMMABILITY

REACTIVITY

PROTECTIVE EQUIPMENT

1

0

0

EYES RESPIRATORY HANDS BODY

(BLUE)

(RED)

(YELLOW)

For routine industrial applications

HAZARDOUS MATERIAL INFORMATION

SYSTEM

B

 See

 Section 8

 See

 Section 8

HEALTH

FLAMMABILITY

REACTIVITY

PROTECTIVE EQUIPMENT

3

0

0

EYES RESPIRATORY HANDS BODY

(BLUE)

(RED)

(YELLOW)

For routine industrial applications

HAZARDOUS MATERIAL INFORMATION

SYSTEM

X

 See

 Section 8

 See

 Section 8
24

ACUTE: The most significant hazard associated with this gas is inhalation of oxygen-deficient atmospheres. 

Symptoms of oxygen deficiency include respiratory difficulty, headache, dizziness and nausea. At high

concentrations, unconsciousness or death may occur. Contact with cryogenic liquid or rapidly expanding gases may

cause frostbite.

CHRONIC: There are currently no known adverse health effects associated with chronic exposure to Nitrogen.

TARGET ORGANS: Respiratory system.
25

.

PART II What should I do if a hazardous situation occurs?

4. FIRST-AID MEASURES

RESCUERS SHOULD NOT ATTEMPT TO RETRIEVE VICTIMS OF EXPOSURE TO NITROGEN

WITHOUT ADEQUATE PERSONAL PROTECTIVE EQUIPMENT. At a minimum, Self-Contained

Breathing Apparatus Personal Protective equipment should be worn.

Remove victim(s) to fresh air, as quickly as possible. Trained personnel should administer supplemental oxygen

and/or cardio-pulmonary resuscitation, if necessary. Only trained personnel should administer supplemental oxygen.

In case of frostbite, place the frostbitten part in warm water. DO NOT USE HOT WATER. If warm water is not

available, or is impractical to use, wrap the affected parts gently in blankets. Alternatively, if the fingers or hands are

frostbitten, place the affected area of the body in the armpit. Encourage victim to gently exercise the affected part

while being warmed. Seek immediate medical attention.

Victim(s) must be taken for medical attention. Rescuers should be taken for medical attention, if necessary. Take

copy of label and MSDS to physician or other health professional with victim(s).

5. FIRE-FIGHTING MEASURES

FLASH POINT: Not applicable.

AUTOIGNITION TEMPERATURE: Not applicable.

FLAMMABLE LIMITS (in air by volume, %):

Lower (LEL): Not applicable.

Upper (UEL): Not applicable.

FIRE EXTINGUISHING MATERIALS: Non-flammable, inert gas. Use extinguishing media appropriate for

surrounding fire.

UNUSUAL FIRE AND EXPLOSION HAZARDS: Nitrogen does not burn; however, containers, when involved in fire,

may rupture or burst in the heat of the fire.

RESPONSE TO FIRE INVOLVING CRYOGEN: Cryogenic liquids can be particularly dangerous during fires because

of their potential to rapidly freeze water. Careless use of water may cause heavy icing. Furthermore, the relatively

warm water greatly increases the evaporation rate of Nitrogen. If large concentrations of Nitrogen gas are present,

the water vapor in the surrounding air will condense, creating a dense fog that may make it difficult to find fire exits

or equipment. Liquid Nitrogen, when exposed to the atmosphere, will produce a cloud of ice/fog in the air upon its

release.

Explosion Sensitivity to Mechanical Impact: Not Sensitive.

Explosion Sensitivity to Static Discharge: Not Sensitive.

NITROGEN GAS LIQUID NITROGEN

3

0

HEALTH 0

FLAMMABILITY

REACTIVITY

OTHER

NFPA RATING

See Section 16 for Definition of Ratings

1

0

HEALTH 0

FLAMMABILITY

REACTIVITY

OTHER

NFPA RATING
26

SPECIAL FIRE-FIGHTING PROCEDURES: Structural fire-fighters must wear Self-Contained Breathing Apparatus

and full protective equipment. Move fire-exposed cylinders if it can be done without risk to firefighters. Otherwise,

cool containers with hose stream and protect personnel. Withdraw immediately in case of rising sounds from venting

safety device or any discoloration of tanks due to the fire.

6. ACCIDENTAL RELEASE MEASURES

SPILL AND LEAK RESPONSE: Uncontrolled releases should be responded to by trained personnel using preplanned procedures. Proper protective equipment should be used. In case of a release, clear the affected area and

protect people.

Minimum Personal Protective Equipment should be Level B: protective clothing, mechanically-resistant gloves

and Self-Contained Breathing Apparatus. Locate and seal the source of the leaking gas. Allow the gas to

dissipate. Monitor the surrounding area for oxygen levels. The atmosphere must have at least 19.5 percent oxygen

before personnel can be allowed in the area without Self-Contained Breathing Apparatus. Attempt to close the main

source valve prior to entering the area. If this does not stop the release (or if it is not possible to reach the valve),

allow the gas to release in-place or remove it to a safe area and allow the gas to be released there.

RESPONSE TO CRYOGENIC RELEASE: Clear the affected area and allow the liquid to evaporate and the gas to

dissipate. After the gas is formed, follow the instructions provided in the previous paragraph. If the area must be

entered by emergency personnel, SCBA, Kevlar gloves, and appropriate foot and leg protection must be worn.
27

PART III How can I prevent hazardous situations from occurring?

7. HANDLING and STORAGE

WORK PRACTICES AND HYGIENE PRACTICES: As with all chemicals, avoid getting Nitrogen IN YOU. Do not

eat or drink while handling chemicals. Be aware of any signs of dizziness or fatigue; exposures to fatal

concentrations of Nitrogen could occur without any significant warning symptoms, due to oxygen deficiency.

STORAGE AND HANDLING PRACTICES: Cylinders should be stored in dry, well-ventilated areas away from

sources of heat. Compressed gases can present significant safety hazards. Store containers away from heavily

trafficked areas and emergency exits. Post “No Smoking or Open Flames” signs in storage or use areas.

SPECIAL PRECAUTIONS FOR HANDLING GAS CYLINDERS: Protect cylinders against physical damage. Store

in cool, dry, well-ventilated, fireproof area, away from flammable materials and corrosive atmospheres. Store away

from heat and ignition sources and out of direct sunlight. Do not store near elevators, corridors or loading docks.

 Do not allow area where cylinders are stored to exceed 52°C (125°F). Isolate from incompatible materials such as

magnesium (see Section 10, Stability and Reactivity for more information), which can react violently. Use only

storage containers and equipment (pipes, valves, fittings to relieve pressure, etc.) designed for the storage of Liquid

Nitrogen. Do not store containers where they can come into contact with moisture. Cylinders should be stored

upright and be firmly secured to prevent falling or being knocked over. Cylinders can be stored in the open, but in

such cases, should be protected against extremes of weather and from the dampness of the ground to prevent

rusting. Keep Dewar flasks covered with loose fitting cap. This prevents air or moisture from entering the container,

yet allows pressure to escape. Use only the stopper or plug supplied with the container. Ensure that ice does not

form in the neck of flasks. If the neck of Dewar flask is blocked by ice or “frozen” air, follow manufacturer’s

instruction for removing it. Ice can also cause pressure release valves to fail. Never tamper with pressure relief

devices. The following rules are applicable to situations in which cylinders are being used:

Before Use: Move cylinders with a suitable hand-truck. Do not drag, slide or roll cylinders. Do not drop cylinders

or permit them to strike each other. Secure cylinders firmly. Leave the valve protection cap in-place (if provided),

until cylinder is ready for use.

During Use: Use designated CGA fittings and other support equipment. Do not use adapters. Do not heat cylinder

by any means to increase the discharge rate of the product from the cylinder. Use check valve or trap in discharge

line to prevent hazardous backflow into the cylinder. Do not use oils or grease on gas-handling fittings or equipment.

After Use: Close main cylinder valve. Replace valve protection cap (if provided). Mark empty cylinders “EMPTY”.

NOTE: Use only DOT or ASME code containers. Earth-ground and bond all lines and equipment associated with

this product. Close valve after each use and when empty. Cylinders must not be recharged except by or with the

consent of owner. For additional information refer to the Compressed Gas Association Pamphlet P-1, Safe Handling

of Compressed Gases in Containers. For cryogenic liquids, refer to CGA P-12, Safe Handling of Cryogenic Liquids.

 Also see CGA P-9, the Inert Gases, Argon, Nitrogen, and Helium; CGA P-14, Accident Prevention in Oxygen Rich

and Oxygen Deficient Atmospheres; CGA Safety Bulletin SB-2, Oxygen Deficient Atmospheres.

PROTECTIVE PRACTICES DURING MAINTENANCE OF CONTAMINATED EQUIPMENT: Follow practices indicated

in Section 6 (Accidental Release Measures). Make certain application equipment is locked and tagged-out safely.

 Purge gas handling equipment with inert gas (e.g., nitrogen) before attempting repairs. 
28

8. EXPOSURE CONTROLS - PERSONAL PROTECTION

VENTILATION AND ENGINEERING CONTROLS: Use with adequate ventilation to maintain oxygen levels above

19.5% in the workplace. Local exhaust ventilation is preferred, because it prevents Nitrogen dispersion into the work

place by eliminating it at its source. If appropriate, install automatic monitoring equipment to detect the level of

oxygen.

RESPIRATORY PROTECTION: Maintain oxygen levels above 19.5% in the workplace. Use supplied air respiratory

protection if oxygen levels are below 19.5% or during emergency response to a release of Nitrogen. If respiratory

protection is required, follow the requirements of the Federal OSHA Respiratory Protection Standard (29 CFR

1910.134), or equivalent State standards.

EYE PROTECTION: Splash goggles, face-shields or safety glasses. Face-shields must be worn when handling

cryogenic Nitrogen.

HAND PROTECTION: Wear mechanically resistant-gloves when handling cylinders of Nitrogen. Use lowtemperature protective gloves (e.g., Kevlar) when working with containers of Liquid Nitrogen.

BODY PROTECTION: Use body protection appropriate for task. Transfer of large quantities under pressure may

require protective equipment appropriate to protect employees from splashes of liquefied product, as well provide

sufficient insulation from extreme cold.

9. PHYSICAL and CHEMICAL PROPERTIES

VAPOR DENSITY: 1.153 kg/m3 (0.072 lb/ft3) EVAPORATION RATE (nBuAc = 1): Not

applicable.

SPECIFIC GRAVITY (air = 1): 0.967 FREEZING POINT: -210°C (-345.8°F)

SOLUBILITY IN WATER (v/v): 1.49% BOILING POINT @1 atm: -320.4°F (-195.8°C)

EXPANSION RATIO: 696.5 (cryogenic liquid) pH: Not applicable.

ODOR THRESHOLD: Not applicable. Odorless. VAPOR PRESSURE (psia): Not applicable.

COEFFICIENT WATER/OIL DISTRIBUTION: Log Kow = 0.92. SPECIFIC VOLUME (ft3

/lb): 13.8

APPEARANCE AND COLOR: Nitrogen is a colorless, odorless gas or a colorless and odorless, cryogenic liquid.

HOW TO DETECT THIS SUBSTANCE (warning properties): There are no unusual warning properties associated

with a release of Nitrogen. In terms of leak detection, fittings and joints can be painted with a soap solution to detect

leaks, which will be indicated by a bubble formation.

10. STABILITY and REACTIVITY

STABILITY: Normally stable in gaseous state. With cryogenic liquid, when exposed to air, oxygen in the air may

condense into the Liquid Nitrogen. Liquid Nitrogen contaminated with oxygen may present the same hazards as

Liquid Oxygen and could react violently with organic materials, such as oil and grease.

DECOMPOSITION PRODUCTS: None

MATERIALS WITH WHICH SUBSTANCE IS INCOMPATIBLE: Titanium, neodymium, lithium, zirconium and ozone

react with Nitrogen. Calcium, strontium, and barium will react with red heat to form nitrides. Hydrogen reacts on

sparking to form ammonia. Liquid Nitrogen in cryogenic grinding of fatty materials can lead to an explosion. A

mixture of magnesium powder and Liquid Nitrogen reacts very violently when lit with a fuse, forming magnesium

nitride. Liquid Nitrogen is not corrosive to metals.

HAZARDOUS POLYMERIZATION: Will not occur.

CONDITIONS TO AVOID: Contact with incompatible materials. Cylinders exposed to high temperatures or direct

flame can rupture or burst.
29

PART IV Is there any other useful information about this material?

11. TOXICOLOGICAL INFORMATION

TOXICITY DATA: The following toxicology data for pure Nitrogen are given below.

Eye Irritation (rabbit): Liquid Nitrogen poured into the eye for one or two seconds with the lids held apart, produced no discernible injury. When

the exposure was extended to five seconds, slight lesions of the cornea were observed. By the next day, all eyes were entirely normal.

SUSPECTED CANCER AGENT: Nitrogen is not found on the following lists: FEDERAL OSHA Z LIST, NTP,

CAL/OSHA, IARC; therefore it is not considered to be, nor suspected to be a cancer-causing agent by these

agencies.

IRRITANCY OF PRODUCT: Contact with rapidly expanding gases can cause frostbite and damage to exposed skin

and eyes.

SENSITIZATION OF PRODUCT: Nitrogen is not a sensitizer upon prolonged or repeated contact.

REPRODUCTIVE TOXICITY INFORMATION: Listed below is information concerning the effects of Nitrogen on the

human reproductive system.

Mutagenicity: Nitrogen is not expected to cause mutagenic effects in humans.

Embryotoxicity: Nitrogen is not expected to cause embryotoxic effects in humans.

Teratogenicity: Nitrogen is not expected to cause teratogenic effects in humans.

Reproductive Toxicity: Nitrogen is not expected to cause adverse reproductive effects in humans.

A mutagen is a chemical which causes permanent changes to genetic material (DNA) such that the changes will

propagate through generation lines. An embryotoxin is a chemical which causes damage to a developing embryo

(e.g., within the first eight weeks of pregnancy in humans), but the damage does not propagate across generational

lines. A teratogen is a chemical which causes damage to a developing fetus, but the damage does not propagate

across generational lines. A reproductive toxin is any substance which interferes in any way with the reproductive

process.

MEDICAL CONDITIONS AGGRAVATED BY EXPOSURE: Pre-existing respiratory conditions may be aggravated

by overexposure to Nitrogen.

RECOMMENDATIONS TO PHYSICIANS: Administer oxygen, if necessary. Treat symptoms and reduce

overexposure.

BIOLOGICAL EXPOSURE INDICES (BEIs): Currently, Biological Exposure Indices (BEIs) are not applicable to

Nitrogen.

12. ECOLOGICAL INFORMATION

ENVIRONMENTAL STABILITY: Nitrogen occurs naturally in the atmosphere. The gas will be dissipated rapidly in

well-ventilated areas.

NITROGEN: Log Kow = 0.92; Water solubility = 1.49% v/v (25EC, 1 atm.).

EFFECT OF MATERIAL ON PLANTS or ANIMALS: Any adverse effect on animals would be related to oxygen

deficient environments. No adverse effect is anticipated to occur to plant-life, except for frost produced in the

presence of rapidly expanding gases. 

EFFECT OF CHEMICAL ON AQUATIC LIFE: No evidence is currently available on the effects of Nitrogen on aquatic

life.

13. DISPOSAL CONSIDERATIONS

PREPARING WASTES FOR DISPOSAL: Waste disposal must be in accordance with appropriate Federal, State,

and local regulations. Return cylinders with any residual product to Airgas Inc. Do not dispose of locally.
30

14. TRANSPORTATION INFORMATION

THIS MATERIAL IS HAZARDOUS AS DEFINED BY 49 CFR 172.101 BY THE U.S. DEPARTMENT OF

TRANSPORTATION.

Nitrogen Gas: Nitrogen Liquid:

PROPER SHIPPING NAME: Nitrogen, compressed Nitrogen, refrigerated liquid

HAZARD CLASS NUMBER and DESCRIPTION: 2.2 (Non-Flammable Gas) 2.2 (Non-Flammable

Gas)

UN IDENTIFICATION NUMBER: UN 1066 UN 1977

PACKING GROUP: Not Applicable Not Applicable

DOT LABEL(S) REQUIRED: Non-Flammable Gas Non-Flammable Gas

NORTH AMERICAN EMERGENCY RESPONSE GUIDEBOOK NUMBER (1996): 121 (Gas); 120 (Liquid)

MARINE POLLUTANT: Nitrogen is not classified by the DOT as a Marine Pollutant (as defined by 49 CFR 172.101,

Appendix B).

TRANSPORT CANADA TRANSPORTATION OF DANGEROUS GOODS REGULATIONS: THIS MATERIAL IS

CONSIDERED AS DANGEROUS GOODS. Use the above information for the preparation of Canadian Shipments.

15. REGULATORY INFORMATION

U.S. SARA REPORTING REQUIREMENTS: Nitrogen is not subject to the reporting requirements of Sections 302,

304, and 313 of Title III of the Superfund Amendments and Reauthorization Act.

U.S. SARA THRESHOLD PLANNING QUANTITY: Not applicable.

U.S. CERCLA REPORTABLE QUANTITY (RQ): Not applicable.

CANADIAN DSL/NDSL INVENTORY STATUS: Nitrogen is on the DSL Inventory.

U.S. TSCA INVENTORY STATUS: Nitrogen is on the TSCA Inventory.

OTHER U.S. FEDERAL REGULATIONS: Not applicable.

U.S. STATE REGULATORY INFORMATION: Nitrogen is covered under the following specific State regulations:

Alaska - Designated Toxic and Hazardous

Substances: No.

California - Permissible Exposure Limits

for Chemical Contaminants: Nitrogen.

Florida - Substance List: No.

Illinois - Toxic Substance List: No.

Kansas - Section 302/313 List: No.

Massachusetts - Substance List: No.

Michigan - Critical Materials Register: No.

Minnesota - List of Hazardous Substances:

 No.

Missouri - Employer Information/Toxic

Substance List: No.

New Jersey - Right to Know Hazardous

Substance List: Nitrogen.

North Dakota - List of Hazardous

Chemicals, Reportable Quantities: No.

Pennsylvania - Hazardous Substance List:

 Nitrogen.

Rhode Island - Hazardous Substance List:

Nitrogen. 

Texas - Hazardous Substance List: No.

West Virginia - Hazardous Substance List:

No.

Wisconsin - Toxic and Hazardous

Substances: No.
31

LABELING (For Compressed Gas):

CAUTION: HIGH PRESSURE GAS.

CAN CAUSE RAPID SUFFOCATION.

Store and use with adequate ventilation.

Use equipment rated for cylinder pressure.

Close valve after each use and when empty.

Use in accordance with the Material Safety Data Sheet.

FIRST AID: IF INHALED, remove to fresh air. If not breathing, give artificial respiration. If breathing is

difficult, give oxygen. Call a physician.

DO NOT REMOVE THIS PRODUCT LABEL.

LABELING (for Liquid):

ALWAYS KEEP CONTAINER IN UPRIGHT POSITION.

WARNING: EXTREMELY COLD LIQUID AND GAS UNDER PRESSURE.

CAN CAUSE RAPID SUFFOCATION.

CAN CAUSE SEVERE FROSTBITE.

Store and use with adequate ventilation.

Do not get liquid in eyes, on skin or clothing.

For liquid withdrawal, wear face shield and gloves.

Do not drop. Use hand truck for container movement.

Close valve after each use and when empty.

Use in accordance with the Material Safety Data Sheet.

FIRST-AID: IF INHALED, remove to fresh air. If not breathing, give artificial respiration. If breathing is

difficult, give oxygen. Call a physician.

IN CASE OF FROSTBITE, obtain immediate medial attention.

DO NOT REMOVE THIS PRODUCT LABEL.

CANADIAN WHMIS SYMBOLS: Class A: Compressed Gases
32

16. OTHER INFORMATION

PREPARED BY: CHEMICAL SAFETY ASSOCIATES, Inc. 

9163 Chesapeake Drive, San Diego, CA 92123-1002

619/565-0302 

The information contained herein is based on data considered accurate. However, no warranty is expressed or implied regarding the accuracy of these data or the results to be obtained

from the use thereof. AIRGAS, Inc. assumes no responsibility for injury to the vendee or third persons proximately caused by the material if reasonable safety procedures are not adhered

to as stipulated in the data sheet. Additionally, AIRGAS, Inc. assumes no responsibility for injury to vendee or third persons proximately caused by abnormal use of the material even if

reasonable safety procedures are followed. Furthermore, vendee assumes the risk in his use of the material.

DEFINITIONS OF TERMS

A large number of abbreviations and acronyms appear on a MSDS. Some of these which are commonly used include the following:

CAS #: This is the Chemical Abstract Service Number which uniquely identifies each constituent. It is used for computer-related searching.

EXPOSURE LIMITS IN AIR:

ACGIH - American Conference of Governmental Industrial Hygienists, a professional association which establishes exposure limits. TLV -

Threshold Limit Value - an airborne concentration of a substance which represents conditions under which it is generally believed that nearly

all workers may be repeatedly exposed without adverse effect. The duration must be considered, including the 8-hour Time Weighted Average

(TWA), the 15-minute Short Term Exposure Limit, and the instantaneous Ceiling Level (C). Skin absorption effects must also be considered.

OSHA - U.S. Occupational Safety and Health Administration.

PEL - Permissible Exposure Limit - This exposure value means exactly the same as a TLV, except that it is enforceable by OSHA. The OSHA

Permissible Exposure Limits are based in the 1989 PELs and the June, 1993 Air Contaminants Rule (Federal Register: 58: 35338-35351 and

58: 40191). Both the current PELs and the vacated PELs are indicated. The phrase, “Vacated 1989 PEL,” is placed next to the PEL which

was vacated by Court Order.

IDLH - Immediately Dangerous to Life and Health - This level represents a concentration from which one can escape within 30-minutes without

suffering escape-preventing or permanent injury. The DFG - MAK is the Republic of Germany’s Maximum Exposure Level, similar to the U.S.

PEL. NIOSH is the National Institute of Occupational Safety and Health, which is the research arm of the U.S. Occupational Safety and Health

Administration (OSHA). NIOSH issues exposure guidelines called Recommended Exposure Levels (RELs). When no exposure guidelines

are established, an entry of NE is made for reference.

HAZARD RATINGS:

HAZARDOUS MATERIALS IDENTIFICATION SYSTEM: Health Hazard: 0 (minimal acute or chronic exposure hazard); 1 (slight acute or

chronic exposure hazard); 2 (moderate acute or significant chronic exposure hazard); 3 (severe acute exposure hazard; onetime overexposure

can result in permanent injury and may be fatal); 4 (extreme acute exposure hazard; onetime overexposure can be fatal). Flammability Hazard:

0 (minimal hazard); 1 (materials that require substantial pre-heating before burning); 2 (combustible liquid or solids; liquids with a flash point

of 38-93°C [100-200°F]); 3 (Class IB and IC flammable liquids with flash points below 38°C [100°F]); 4 (Class IA flammable liquids with flash

points below 23°C [73°F] and boiling points below 38°C [100°F]. Reactivity Hazard: 0 (normally stable); 1 (material that can become unstable

at elevated temperatures or which can react slightly with water); 2 (materials that are unstable but do not detonate or which can react violently

with water); 3 (materials that can detonate when initiated or which can react explosively with water); 4 (materials that can detonate at normal

temperatures or pressures).

NATIONAL FIRE PROTECTION ASSOCIATION: Health Hazard: 0 (material that on exposure under fire conditions would offer no hazard

beyond that of ordinary combustible materials); 1 (materials that on exposure under fire conditions could cause irritation or minor residual injury);

2 (materials that on intense or continued exposure under fire conditions could cause temporary incapacitation or possible residual injury); 3

(materials that can on short exposure could cause serious temporary or residual injury); 4 (materials that under very short exposure could cause

death or major residual injury).

NATIONAL FIRE PROTECTION ASSOCIATION (Continued): Flammability Hazard and Reactivity Hazard: Refer to definitions for

“Hazardous Materials Identification System”.

FLAMMABILITY LIMITS IN AIR:

Much of the information related to fire and explosion is derived from the National Fire Protection Association (NFPA). Flash Point - Minimum

temperature at which a liquid gives off sufficient vapors to form an ignitable mixture with air. Autoignition Temperature: The minimum

temperature required to initiate combustion in air with no other source of ignition. LEL - the lowest percent of vapor in air, by volume, that will

explode or ignite in the presence of an ignition source. UEL - the highest percent of vapor in air, by volume, that will explode or ignite in the

presence of an ignition source.

TOXICOLOGICAL INFORMATION:

Possible health hazards as derived from human data, animal studies, or from the results of studies with similar compounds are presented.

Definitions of some terms used in this section are: LD50 - Lethal Dose (solids & liquids) which kills 50% of the exposed animals; LC50 - Lethal

Concentration (gases) which kills 50% of the exposed animals; ppm concentration expressed in parts of material per million parts of air or water;

mg/m3 concentration expressed in weight of substance per volume of air; mg/kg quantity of material, by weight, administered to a test subject,

based on their body weight in kg. Data from several sources are used to evaluate the cancer-causing potential of the material. The sources

are: IARC - the International Agency for Research on Cancer; NTP - the National Toxicology Program, RTECS - the Registry of Toxic Effects

of Chemical Substances, OSHA and CAL/OSHA. IARC and NTP rate chemicals on a scale of decreasing potential to cause human cancer

with rankings from 1 to 4. Subrankings (2A, 2B, etc.) are also used. Other measures of toxicity include TDLo, the lowest dose to cause a

symptom and TCLo the lowest concentration to cause a symptom; TDo, LDLo, and LDo, or TC, TCo, LCLo, and LCo, the lowest dose (or

concentration) to cause lethal or toxic effects. BEI - Biological Exposure Indices, represent the levels of determinants which are most likely

to be observed in specimens collected from a healthy worker who has been exposed to chemicals to the same extent as a worker with inhalation

exposure to the TLV. Ecological Information: EC is the effect concentration in water.

REGULATORY INFORMATION:

This section explains the impact of various laws and regulations on the material. EPA is the U.S. Environmental Protection Agency. WHMIS

is the Canadian Workplace Hazardous Materials Information System. DOT and TC are the U.S. Department of Transportation and the

Transport Canada, respectively. Superfund Amendments and Reauthorization Act (SARA); the Canadian Domestic/Non-Domestic Substances

List (DSL/NDSL); the U.S. Toxic Substance Control Act (TSCA); Marine Pollutant status according to the DOT; the Comprehensive

Environmental Response, Compensation, and Liability Act (CERCLA or Superfund); and various state regulations.