Safety and occupational healthSH-007

Engulfment during cement-silo cleaning

Keystone Cement Company · Bath, Pennsylvania, USA · 1999

Use this record when

The decision this case can inform

Use this record when deciding whether silo cleaning can remain remote or whether any proposed entry is exposed to unstable overhead deposits or material flow.

Evidence scope

Final MSHA fatal-accident record for a contractor cleaning a cement silo. It identifies missing barriers but is not a complete confined-space or silo-entry procedure.

Source-supported facts

What the public record actually establishes

4 sourced points
  1. F1

    More than two feet of caked cement remained on parts of the silo wall above the access point.

  2. F2

    The worker entered despite having expressed that the condition was unsafe.

  3. F3

    No staging or safety line protected the worker, and the discharge screw had not been locked out.

  4. F4

    Falling cement engulfed the worker; MSHA also noted that available mechanical cleaning had not been fully used.

Structured interpretation

Facts and reported results are kept separate from the lesson a plant may choose to test.

01

Operating context

More than 2 ft of caked cement remained on parts of a silo wall above an access point during cleaning.

02

Intervention or finding

MSHA concluded entry under falling-material danger was primary; lack of staging and safety line and failure to isolate discharge contributed.

03

Documented result

Falling cement engulfed a contractor inside the silo.

04

Plant interpretation

Prefer remote/mechanical cleaning and authorize entry only after overhead stability, material-flow isolation, safe positioning, and rescue are verified.

05

Transfer boundary

Not a complete confined-space procedure.

Before applying the lesson

Questions to verify at your plant

These are decision checks, not operating instructions. Resolve them through local risk assessment, technical review, and authorization.

  1. 01

    Has remote or mechanical removal been exhausted before anyone considers entry?

  2. 02

    How is overhead material stability independently assessed and kept under control throughout the work?

  3. 03

    Are every fill, discharge, pneumatic, mechanical, and gravity flow path positively isolated?

  4. 04

    Can a worker stop the job without pressure, and is a credible non-entry rescue capability ready?