OSHA Hazard Information Bulletins
August 30, 1994
| MEMORANDUM FOR: |
REGIONAL ADMINISTRATORS |
| THROUGH: |
JIMMY ROBERTS
Acting Director
Office of Field Programs |
| FROM: |
CHARLES E. ADKINS, CIH
Acting Director
Directorate of Technical Support |
| SUBJECT: |
Hazard Information Bulletin(1): Potential
Over Pressurization of Bromochlorodimethylhydantoin
(BCDMH) Treatment Systems. |
___________
FOOTNOTE(1) The Directorate of Technical Support issues Hazardous
Information Bulletins (HIB) in accordance with OSHA Instruction CPL 2.65
to provide relevant information regarding unrecognized or misunderstood
health hazards, inadequacies of materials, devices, techniques, and safety
engineering controls. HIBs are initiated based on information provided by
the field staff, studies, and concerns expressed on information provided by
the field employers, and the public. Information is compiled based on a
thorough evaluation of available facts, in coordination with the appropriate
parties.
The Austin Area Office has brought to our attention potential health and
safety hazards which may occur by utilizing a particular dispensing system to
dose a dry chemical microbiocide, Bromochlorodimethylhydantoin (BCDMH) in
commercial and industrial cooling water systems. In Region VI, an incident
occurred in which newly installed BCDMH treatment systems experienced an
unexpected and rapid evolution of gases causing the feed system to
over-pressurize and rupture. The exact cause of the evolution of gases was
not determined.
The dispensing system containing BCDMH is a transportable steel tank with a
chemical resistant liner (see attachment #1). The steel tank serves as a
combination of a bulk shipping container and a dissolution feeder. This type
of dispensing system is equipped with connections which allow for the
incorporation of a sight gauge level indicator to permit a visual inspection
of the chemical bed height and a pressure relief device. These accessories
are incorporated into a single unit (see attachment #2) and attached to the
vessel on the small blind flange on the outer part of the top dome. Although
pressure may be developed within these units, there is no specific OSHA or
consensus standard that would require a pressure relief device to be
installed on these tanks.
According to the Nalco Chemical Company, the distributor of this type of
BCDMH dispensing device, the BCDMH chemical contains approximately 57 percent
available halogen. The available halogen consists of bromine and chlorine
and may evolve heat and hazardous gases under certain conditions. This
chemical should never be mixed with organic chemicals, oxidizable chemicals
or strong reducing agents. Data generated from the Hartman Dust Explosion
Hazard Test indicate that the dry BCDMH product, by itself, is not ignitable.
Data also indicate that BCDMH dust-air mixtures may ignite or explode.
The
distributor recommends that this chemical dispensing system be stored under
cool and dry conditions, and that only make-up cooled water be used through
it.
It is strongly recommended that regardless of the type of the dispensing
device utilizing, BCDMH must be completely flooded with water at all times.
Although not required by the pressure vessel standard, the distributor
recommends the use of venting to ensure complete flooding of the chemical bed
with water and a pressure relief device for unexpected increases in pressure.
The Material Safety Data Sheet (MSDS) on BCDMH indicates water as the
appropriate extinguishing medium in case of fire. An ammonium phosphate
extinguisher should not be used due to the potential volatile reaction it may
have with bromine. OSHA requires that a copy of the MSDS be maintained at
the site of use.
BCDMH can cause an acute inhalation hazard due to irritation of the nose and
throat. OSHA requires the use of personal protective equipment when working
with chemicals such as BCDMH. Appropriate personal protective equipment such
as NIOSH approved respirators, impermeable gloves, boots, aprons, face shield
and goggles may be required.
Please distribute this bulletin to a Area Offices, State Plan States
Consultation Projects and appropriate and trade associations.
Attachments
Attachment 1.
BCDMH Bulk Shipping Container and Dissolution Feeder
Attachment 2.
Combined Sight Gauge Level Indicator and Pressure Relife Device |
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