A new thermal boot was introduced in the early 1950s, for conditions in Korea, replacing the inadequate WW II vintage Shoepacs. The new boot was issued first to the Marine Corps then to the Army. The boot was designed with two layers of rubber with a layer of wool pile insulating material in between. They were referred to as thermos boots because of a sealed air layer within the insulating material. Neither air nor moisture could be exchanged with that layer due to the sealed rubber, preventing heat from escaping the foot, protecting the wearer from frostbite down to -20° F. By mid-November 1951, all Army and Marine Corps troops in Korea had the new boots. Their bulbous large size and black color quickly led to a new name: "Mickey Mouse" boots. The style is also sometimes called a "Blucher Boot."
In the 1960s, an air valve was added to equalize pressure in the boot during air transportation. A second version of the boot, in white, called "Bunny" boots, offered protection down to -60° F.
In the autumn of 1951, the 1st Marine Division received a new piece of cold weather clothing: the Boot, Combat, Rubber, Insulated (or Insulated Rubber Boot.) No one called it anything else but "Mickey Mouse Boots" since their outsized shape and black color gave the wearer some podiatric similarity to Hollywood's famous rodent. Other names for the hoots were less complimentary, but compared with the "shoe-pacs" they replaced, the Mickey Mouse boots quickly proved their value in preventing frozen feet.
The U.S. Army had conducted experiments with a cold weather boot during and after World War II, but by 1949 it had abandoned the effort since none of the experimental prototypes met Army standards for long-distance marching. Less concerned about the marching requirement, the Navy and Marine Corps conducted their own boot tests, 1948-1951, and concluded that one boot had merit. The field tests included wear in all Sorts of cold weather and terrain conditions, and
the Marines hiked in the boot and found it at least acceptable as winter footwear since no one marched very fast or far in inclement conditions anyway. The Mickey Mouse boots arrived in Korea in August 1951.
Cold weather experience in Korea showed that the Mickey Mouse Boots had to be used with caution since the boots could turn the unwary and careless Marine into a frostbite casualty. The boots trapped more than heat. They also trapped sweat, and even if the feet remained warm, the moisture - with its ability to transfer heat four times more rapidly than dry air - accumulated, too. If a Marine did not stay on the move, his feet cooled, and the more sweat-soaked one's socks, the faster one's feet froze. One hour of inactivity could bring on an attack of frostbite. The standard operating procedure, therefore, for Mickey Mouse bootwear included a provision that each Marine had to dry his feet and change to dry socks at
least once a day, preferably more often.
The next worst thing to having frozen feet, however, was preventing frozen feet. Changing socks and drying feet in the open air of a Korean winter tested the staunchest Marines. Units tried to establish a warming tent of some sort where the masochistic ritual could he performed with a hint of comfort and adequate time. Fortunately, the static winter war of 1951-1952 allowed such luxuries and cases of frozen feet in the 1st Marine Division dropped dramatically. The Mickey Mouse boots had come to stay.
This section adapted from US Marines in the Korean War, P466.
Boot, Insulated, Cold Weather: Men's and Women's, Rubber, Black
Starting in 1951, during the Korean War, sealed insulated rubber boots have protected U.S. military personnel from cold injuries to the feet in wet-cold and dry-cold climates, superseding the World War II vintage shoepacs. The black rubber insulated boot, called the "Mickey Mouse Boot," have a seamless inner and outer carcass, direct molded sole, and sealed insulation. An air valve on the outside of each boot is used to compensate for air pressure differentials. The boots are constructed on a double vapor barrier principle, with an air chamber and insulating material sealed between two impermeable barriers of rubber. The outer boot wall or barrier protects the insulation against environmental water and the inner barrier next to the foot protects the insulation against foot perspiration and water vapor. By keeping the insulation dry, the double barriers eliminate the evaporation of moisture from the feet and socks, blocking a major cause of cold injury. The conception of the principle of the sealed insulated boot arose during World War II, with its design and fabrication for initial use in the Korean War.
Initially, the thermal boots were issued in black and offered protection to -20° F temperature in wet or dry conditions. That is, in addition to protection from cold they offered isolation of the feet from snow, slush, mud and water. They are specifically designed for combat personnel who may not have the opportunity to frequently change to dry socks. Insulating material is hermetically sealed into the sides and bottoms of the boots. The insulation takes the place of removable innersoles and the secondary layer of socks worn in other types of cold weather boots. Perspiration from the feet and water spilling over the tops of the boots cannot reach the insulating material because it is sealed-in and always remains dry. Moisture from outside sources or from perspiration may make the socks damp; this dampness is not harmful to the feet, provided they receive proper care such as frequent drying and massaging. If socks are not changed and feet dried regularly (at least twice daily) the skin becomes softened and is more readily chafed or blistered. These effects are occasionally mistaken for superficial frostbite. Only one pair of cushion-sole socks are worn with the boots. Additional socks should not be worn as the feet may become cramped, resulting in restricted blood circulation and cold feet.
Although initially procured for the Korean War, these boots remain an active component of the Extreme Cold Weather ensemble (ECWCS). Later nomenclature was similar to "Boots, Cold Weather, Men’s and Women’s, Rubber Black Insulated, with Release Valve," or "Boot, Extreme Cold Weather" under specification MIL-B-41816. There are a large number of NSNs that apply to these boots, depending on time period and size. The pressure release valve, part of the white boot design, was added to the black boot as well.
The boots and procedures for use are described in FM 31-70 Basic Cold Weather Manual.
Boot, Insulated, Cold Weather: Men's and Women's, Rubber, White w/Release valve
The insulated white boot, called the white Mickey Mouse or "Bunny Boot," is designed for wear in cold-dry conditions and will protect the feet in temperatures as low as –60° F. The boots have a seamless inner and outer carcass, direct molded sole, sealed insulation, and an outside air release valve used to compensate for pressure differentials. The sealed insulation exceeds that of the black boots for protection against the hazards of a cold-dry environment. Like the black boots, the white boots are worn over one pair of cushion sole socks. The air release valve provides airborne troops a means of equalizing external and internal air pressures when undergoing extreme changes in altitude. This valve must remain closed at all other times to prevent the possibility of introducing any amount of moisture into the insulation of the boot and rendering it permanently unserviceable.
These boots remain an active component of the Extreme Cold Weather ensemble (ECWCS). Later nomenclature was similar to "Boots Cold Weather, Men’s and Women’s, Rubber White, Insulated, with Release Valve" or "Boot, Extreme Cold Weather" under specification MIL-B-41816. There are a large number of NSNs that apply to these boots, depending on time period and size.
The boots and procedures for use are described in FM 31-70 Basic Cold Weather Manual.
Problems with Mickey Mouse Boots
While the Mickey Mouse type Extreme Cold Weather boots are the most effective American boots for cold conditions, they have their drawbacks. They are very heavy and bulky and can inhibit rapid movements by soldiers wearing them. The top edge of the boot can chafe the calf on marches, quickly causing a painful sore. The wearer's feet tend to sweat a lot in these boots which can cause problems when clean, dry socks are not available in field conditions. However, the problems are small compared to the cold injuries prevented by these boots.
Labels and Instruction Tags for the Mickey Mouse Boots
Later versions of the Mickey Mouse Boots have two labels stenciled on the outside of the boot (see photos):
KEEP DOUBLE LACED TO HOLD FIRMLY
FOLD GUSSET THIS SIDE ONLY
In addition, near the top of the back are a size label and "US" markings.
Each pair of Mickey Mouse boots is issued with an instruction tag with this text:
BOOTS, COLD WEATHER, INSULATED, RUBBER (BLACK) FOR WET-COLD USE
TYPE 1, CLASS 1, RIGID SOLE
TYPE 1, CLASS 2, FLEXIBLE SOLE AND WITHOUT VALVE
Facts about the insulated boot.
(1) These boots have been designed to protect your feet from cold injury and frost bite in areas where
moisture and cold are critical factors, and where the mean monthly temperature ranges between 14°F
and 68°F. The boot should not be worn where temperatures fall below – 20°F
(2) The part of the boot that keeps the foot warm consists of layers of wool and felt that are sealed
between the rubber inner and outer layers of the boot so that no water can get into the insulation
(3) Marching, running, or heavy work for long periods will cause the feet to sweat, However, this moisture
cannot damage the insulation because of the water-proof rubber lining inside the boot. The feet, even
if damp, will stay warm, After a few days, your feet become used to this feeling. If these boots are worn
continuously, the skin appears wrinkled and white as if it had been soaked in water. Drying the feet
and putting on dry clean socks will cause this condition to disappear. If ice water spills into the boot, it
warms to body temperature rapidly.
(4) FOLLOW THESE INSTRUCTIONS: Wear with one pair of Socks, Wool, Cushion Sole! Fold the top of
the sock over top of boot to prevent slipping and wrinkling. Field trousers are to be worn outside the
(5) SIZES: Boots are supplied in whole sizes. Widths are Extra Narrow, Narrow, Regular, Wide, Extra
Wide. Try on the same size insulated boots as your leather boot. If you wear a half size in leather
boots, try on the next larger or smaller size for proper fit. MAKE SURE THAT INSULATED BOOTS FIT
PROPERLY. THEY HAVE A “SOFT” FIT. Be sure yours are large enough. Fit snug, but not tight. The
boot is double laced through the second eyelets. Loosen laces and draw boot onto foot, seating the
back of the heel firmly into the boot. Pull laces right about the second eyelet firmly to anchor the boot
to the foot. Lace rest of boot comfortably. Fold or tuck fullness of gusset rearward on outer side of leg,
per instructions imprinted on the boot. When doffing boot, loosen laces above second eyelet, then
complete by loosening laces directly below second eyelet.
(6) Change socks at least once daily.
(7) If your feet begin to get cold, button up all your garments and exercise the entire body by swinging
the arms, stamping the feet, and rapid movement of the toes.
(8) Wash the inside of boots with soapy water once a month.
(9) Boots should be inspected after each use for holes, cuts and punctures as the insulation can
become wet if the boot is accidentally punctured. Repair all outside and inside punctures immediately
to prevent moisture from wetting the sealed insulation, using the Emergency Individual
Repair Patch Kit for Insulated Boots. If this kit is not available, temporary repairs can be made by
patching with rubber or friction tape, pressure sensitive adhesive cellophane tape or even chewing
gum. Damaged boots should be turned in for repair or for new boots.
(10) The shelf on the heel holds a ski or snowshoe binding in place.
(11) For Type I Class 1, the air release valve on the outside of the boot equalizes air pressure at different
altitudes. To reduce boot swelling and foot discomfort when the boot is worn in unpressurized
aircraft or at high altitudes, open the valve allowing pressure to escape. Back at lower altitudes,
close again. Be sure to keep closed, except while airborne, to eliminate moisture penetration, DO
NOT TAMPER WITH AIR VALVE. USE ONLY WHEN NEEDED! For Type I, Class 2, no valves are
(12) Do not paint the inside of the boot for identification purposes or polish the boots with shoe polish as
this will result in deterioration of the rubber.
(13) Cleaning: Sprinkle lightly with general purpose scouring powder or similar cleaning powder. Wet a
soap impregnated steel wool pad and rub lightly. Rinse with water.
(14) Trench foot and frostbite are serious cold injuries which can cause painful and permanent disability.
These injuries can be prevented by proper care of your feet. No boot will keep your feet from freezing
if in sub-zero weather you remain motionless for several hours. Wear the insulated boot properly and
DO NOT BECOME A COLD WEATHER CASUALTY.
Replacement Laces for the Mickey Mouse Boots
Replacement laces for these boots are:
Laces, footwear, nylon, flat, both ends tipped, black (NSN 8335-00-945-3969)
Laces, footwear, nylon, flat, both ends tipped, white (NSN 8335-00-131-6538)
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