Temporary Enclosure Long

8/8/2019 Temporary Enclosure Long

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Fatal Incident Involving aTemporary Enclosure at a

Chemical Facility

From an OSHA Technical Information

Bulletin


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Purpose

Provide information

Hazard alert

Requirements and regulations

Recommendations and guidance

Other information


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Incident Description

Facility unit undergoing a turnaround.

2 workers to inspect the flange surfaces

of an open 48-inch piping system. Piping system opened to remove a

piece of process equipment for

cleaning.


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Black Tarp

48 Pipe


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Plastic-wrapped pipe

New moisture-sensitive catalystupstream


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Incident Overview

N2

Injection

Reactor w/newcatalyst

Open 48"Piping

Open Valve

Closed Valve

N2

Venting

Note: Actual process/piping significantly more complex. N2 injection

point 150' and several stories in elevation from pipe opening.

North

South


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Incident Overview

NitrogenPurge

Reactor with

Catalyst

Open valvesto north sideopen piping

In-Line Mixer (removed)

Black Tarp


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Southside open pipe & enclosure

Midday black light inspection.

Black tarps draped to block light. Workers entered enclosure.

No problems with inspection.


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North side open pipe & enclosure

Midday backlight inspection.

Black tarps draped to block light. Workers entered enclosure.

Workers overcome upon entering.


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Incident Conclusions

One worker died, another hospitalized.

N2 throughout system.

Piping system was not straightforward. OSHA cited the employer for 1910.146

Permit-Required Confined Space

violations.


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Permit Required

Confined Space Hazards

Oxygen deficiency

Flammable atmosphere

Toxic atmosphere

Oxygen enrichment

Chemical exposure

Thermal hazards

Electrical shock

Temperature extremes

Engulfment

Mechanical hazards

Trapping/Pinch points

Physical hazards

Slips, Trips, Falls

Unstable working surface

Structural failure

Other recognized hazards


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Nitrogen Hazard

Cant be detected by human senses

N2 displaces oxygen in enclosures

(confined spaces) resulting in oxygen-deficient atmospheres


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Human Response to Oxygen-

Deficient Atmospheres

Atmospheric Oxygen

Concentration [%O2]Possible Consequences

19.5Meets OSHA minimum requirements for

worker protection

8-10

Unconsciousness without warning; so

quickly that individuals cannot help or

protect themselves

6-8 Fatal injury < 6 minutes

4-6 Coma < 40 seconds with subsequent death


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Requirements, Recommendations

& Guidance

If space meets the definition of a PRCS,must follow 1910.146.

Even if not technically a PRCS, 1910.146

recommended. Other OSHA standards may apply:

1910.134 Respiratory Protection IDLH Atmospheres

Recognition that temporary enclosures maybe PRCSs.


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Requirements, Recommendations,

& Guidance

Comprehensive confined space

training.

Particular attention on hazardousatmospheres


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Related Information

OSHA Technical Information Bulletin onincident at: http://www.osha.gov

CSB Morten Report at:http://www.csb.gov/reports/1998/union_carbide/98005lafr.htm

OSHA PRCS Standard, Directive andInterpretation at: http://www.osha.gov

Temporary Enclosure Long

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