Fatal Incident Involving a Temporary Enclosure at a

Chemical Facility

From an OSHA Technical Information Bulletin

PurposeProvide informationHazard alertRequirements and regulationsRecommendations and guidanceOther information

Incident DescriptionFacility 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.

Black Tarp

48” Pipe

Incident Description

Plastic-wrapped pipe New moisture-sensitive catalyst

upstream

Incident Overview

N2

Injection

Reactor w/new catalyst

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

Incident Overview

Nitrogen Purge

Reactor with Catalyst

Open valves to north side open piping

In-Line Mixer (removed)

Black Tarp

Incident DescriptionSouthside open pipe & enclosure

Midday black light inspection. Black tarps draped to block light. Workers entered enclosure. No problems with inspection.

Incident DescriptionNorth side open pipe & enclosure

Midday backlight inspection. Black tarps draped to block light. Workers entered enclosure. Workers overcome upon entering.

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.

Permit RequiredConfined 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

Nitrogen HazardCan’t be detected by human sensesN2 displaces oxygen in enclosures

(confined spaces) resulting in oxygen-deficient atmospheres

Human Response to Oxygen-Deficient Atmospheres

Atmospheric Oxygen Concentration [%O2]

Possible Consequences

19.5Meets OSHA minimum requirements for worker protection

8-10Unconsciousness 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

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 may be PRCSs.

Requirements, Recommendations, & Guidance

Comprehensive confined space training. Particular attention on hazardous

atmospheres

Related Information OSHA Technical Information Bulletin on

incident at: http://www.osha.gov

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

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