Grid production and parts casting involves book casting,
continuous casting, and strip casting. In
all of these processes, lead pigs are melted down and the molten lead is
poured into molds or continuously cast into
grids, strips, or parts. Expanded
metal grid production involves mechanical
operations on the cast strip and is not a source
of airborne lead dust or oxide. The major source of lead exposure in this process is from lead
fumes and lead
oxide which can become easily airborne.
Grid production machine
Potential Sources of
- Drossing the lead pot may increase lead exposure.
- High levels of
lead fumes are generated when
a flame is put in contact with lead, such as when cutting out frozen
- Settled lead dust on surfaces and equipment may become airborne due to exhaust from fuel-powered fork-lifts
or vehicular traffic.
- High exposure to lead fumes can occur when the pig is
into the lead pot.
- Airborne lead dust can migrate from other
areas of the plant
depending on the plant
- Separator boards may become contaminated by using lead contaminated pallets that have not been cleaned
after being returned from the pasting
- Dust may become airborne
as a result of using a rotary sander for cleaning
- Oxide that has collected
on the dross ladle may become airborne while cleaning
or storing it in
an area outside the hood.
Possible Work Practice
a system to minimize the
formation of dross.
- Place a local exhaust ventilation on the lead melting pot and the dross
1, 2, and 3).
Lead Pot and Dross Hood
Scrap Pot and Dross Hood
- Dross with a ladle with holes
in it to allow lead to drain back into the
- Install Laminar
Flow (Supplied Air) Islands at the drossing
exposures exceed the PEL.
- Provide local slot ventilation or a ventilated torch for cutting out frozen
- Suspend plastic curtains to separate the casting areas from the traffic
- Isolate the lead pots from casting
- Handle dross carefully within a ventilated
- Keep the doors closed on the dross cabinets when drossing into the
- Keep the dross covered where air turbulence may cause powdery dross to become
- Cool waste drums under exhaust
- Enclose cooled waste drums with a plastic bag prior to storage (Figure 3).
- Do not add sawdust to the
- Keep dross from calcium and antimonial alloys separate and dry since arsine and stibine
gases could be emitted.
- Slide pigs into the casting pots, where feasible.
- Use a long-handled push rod or mechanical system to feed the pigs into the
- Use separate pallets for grid storage and
pasted plate storage (Figure 4).
- Provide adequate PPE, change of clothes, and shower
rooms (see OSHA Lead Requirements for PPE, Housekeeping, and Hygiene Facilities).
- Ensure ventilation is working
- Use electric powered fork
- Use an automatic conveyance
- Avoid using a rotary sander to clean
- Use dust suppression techniques, such as, using
dust suppression compounds or
- Keep the floor areas and work surfaces around the lead pots and lead storage areas free of oxide
- Scrape metal splashes with a shovel or long-handled