Volume 1
20-40-00
Page 28
OCT 01/01
CORROSION PREVENTION MANUAL
CORROSION REMOVAL TECHNIQUES
PROCEDURE AFTER MERCURY SPILLAGE
1. General
A. The corrosive action of mercury is very rapid; consequently, immediate
action must be taken when mercury spillage has been discovered.
B. Mercury amalgamates readily with aluminum alloys at room temperature if the
oxide film on the aluminum has been scratched or damaged. Once a small area
of aluminum has been amalgamated, corrosion occurs. This process is acceler-ated by moisture and particularly by salt water.
C. The amalgamation of stressed aluminum structure may also result in rapid
cracking similar to stress corrosion cracking.
D. Mercury is not consumed in the amalgamation process. As the aluminum oxi-dizes, it separates from the amalgam and the mercury continues to attack
fresh aluminum.
E. The presence of organic finishes, greases or a thick continuous oxide layer
retards the amalgamation process.
2. Detection
A. A grayish-white powder or fuzzy coating on aluminum surfaces indicates the
presence of corrosion caused by spilled mercury.
B. The presence of even small amounts of mercury can be detected by a sniffer.
This is an electronic device that is sensitive to mercury vapor.
C. X-ray that will show up on the film as small white spots can best detect
Mercury. Corrosion may show up as tree-like forms penetrating a structural
component.
3. Personnel Precautions
WARNING: ALWAYS PROVIDE AMPLE VENTILATION WHILE CLEANING AREAS CONTAMINATED BY
MERCURY.
DO NOT EAT, SMOKE OR BLOW NOSE AFTER CONTACTING MERCURY WITHOUT FIRST
WASHING HANDS THOROUGHLY.
A. Appreciable amounts of mercury will vaporize at normal temperatures to the
extent that a stagnant air mass can become dangerous to personal health.
B. Free mercury or amalgam must not be picked up by hand.
C. Clean tools with soap and hot water or steam bath. Discard drill bits after
use on structure contaminated by mercury.
4. Isolation of Contaminated Areas
A. On discovery of spilled mercury steps should be taken to avoid enlargement
of the contaminated area. The following precautions are advised:
(1)Do not remove access/inspection plates or even fasteners that could
result in the spread of the mercury, until such times as the area has
been thoroughly cleaned up.
(2)If hands become contaminated, do not touch any exposed metal in the sur-rounding area in case it becomes contaminated.
Volume 1
20-41-00
Page 1 OCT 01/01
CORROSION PREVENTION MANUAL
CORROSION REMOVAL TECHNIQUES
PROCEDURE AFTER MERCURY SPILLAGE
(3)Mercury spreads easily from one surface to another by adhering to hands,
shoes, clothes, tools, etc. Keep traffic to a minimum in the contami-nated area.
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