INFORMATION ALERT
  
INFO ALERT #28
  
DATE:  January 21, 1993
  
                FATALITY - PULP MILL BLEACH PLANT HOOD
                     BLOWN OFF DURING STEAM PURGE

HAZARD SUMMARY:

During the unplugging of a steam mixer with steam ("steam purge"), the 
increase in pressure forced the material back up the chute and into 
the washer. The impact of the expelled material blew off the partial 
hood of the pulp washer. The hood (approximate weight: 1,000 pounds) 
landed on a nearby worker, killing him.

Steam mixers are used to increase the effectiveness of bleaching 
chemicals on pulp by raising its temperature. They are meant to 
operate at atmospheric pressure.

LOCATION(S) AND SECTOR(S):

Pulp Mills

SUGGESTED PRECAUTIONS AND APPLICABLE SECTIONS OF THE INDUSTRIAL 
REGULATIONS:

It is recommended that the purging of a plugged steam mixer be done 
using low-pressure water and/or by physically opening the vessel to 
manually remove the stock. These methods are currently in use in many 
mills.

If steam is to be used to purge a plugged mixer, all workers shall be 
evacuated from areas at risk of rupture and discharge (e.g., washer 
and steam mixer areas) to a safe location during a steam purge 
operation.

Although a fully enclosed hood on the washer (as opposed to a partial 
hood) may not contain a steam purge, it would improve containment of 
periodic steam "blow-backs" which occur during normal operation when a 
steam mixer is downstream of a washer.

Any opening in the full-enclosure hood (e.g., inspection doors, 
sampling ports) shall be offset at least 10 feet from the pipe 
connecting the washer to the steam mixer.

Reference: Industrial Regulations (R.R.O 1990, Reg. 851) Sections 
           45(a) and 26.

NOTE:  "Information Alert" is produced by the Occupational Health and  
       Safety Branch, Ministry of Labour for use by Ministry 
       inspectors, health and safety associations and other interested 
       groups or individuals in Ontario.  The goal of this publication  
       is to communicate hazard information as soon as it becomes  
       available to prevent serious injury to workers.  Reproduction  
       and use of these alerts is encouraged.