7.000 LETHAL GAS CHAMBER FUNCTION.
The function of a Lethal Gas Chamber is simple in theory, but complex
in actual usage. Essentially, the executee is sealed into a chamber which
is inwardly pressurized (evacuated) causing any leak of dangerous hydrogen
cyanide gas to be inward. By means of an external actuator, sodium cyanide
pellets (briquets) are dropped into warm, dilute sulfuric acid within the
chamber. Hydrogen Cyanide (Zyklon B) gas is generated within the chamber
due to the chemical reaction of the sodium cyanide and the sulfuric acid.
The released gas surrounds the executee and terminates his life.
After a sufficient time has elapsed, the chamber is ventilated completely,
with air in excess of 80 degrees Fahrenheit, many times over, and the subject
is removed after proper neutralization with ammonia. The prussic acid,
residual to the chemical reaction, must be disposed of. The Chamber must
be neutralized by washing with ammonia and caustic soda or chlorine bleach.
Care must be taken in handling the corpse, cleaning the chamber and gas
generator, and evacuating the gas to see that no one other than the executee
7.001 The Mississippi Lethal Gas Chamber is operated in the following
manner. First, it is tested to determine if all of the plumbing is clear
and tight. This is done by opening Inlet Valve (3) and Outlet Valve (4)
and running tap water into the Acid Mixing Pot (9) for five minutes. This
determines that there are no blockages in the plumbing. Then Valve (4)
is closed and tap water is run into the Acid Mixing Pot filling the Gas
Generator (D) to the floor level of the lethal chamber. The piping in the
pit is then inspected to determine that there are no leaks. The Gas generator
Valve (1) is then closed by utilizing Gas Valve Lever (1), trapping the
water above the valve at floor level. Then, Outlet Valve (4) is opened,
allowing the water to drain into the sewer, since Gas Valve Lever (1) has
opened the Gas Generator Vent Stack Valve (A).
7.002 Next is the vacuum test. First, check the Packing Gland and tighten
the window frames onto the gaskets. Close and seal the door. Then place
some water around Air Intake Valve (2) (to ensure a tight seal) and close
Valve (2) by actuating Lever (2). Open Air Exhaust Valve (5) by means of
Fan Damper Lever (5) and start exhaust Fan. This will pull a vacuum on
the chamber. We must now monitor the Manometer (6) to determine if it remains
constant or indicates there is a leak. If there is no leak, the following
is done to effect an execution: turn off fan and open the Air Intake Valve
(2). This relieves the vacuum. Open the door. The heat must be turned on
and the Death House brought to and maintained at a temperature of over
80 degrees Fahrenheit to prevent condensation of the hydrocyanic acid on
the interior of the gas chamber, which would make cleanup extremely dangerous.
Hydrogen cyanide gas condenses at 78.3 degrees Fahrenheit (25.7 degrees
Celsius) and the intake air in the control room must be kept above this
7.003 Utilizing the Gas Valve Lever (1), the Gas Generator Valve (10)
should be opened and closed to eliminate any water trapped above the floor
in the last test. The Sodium Cyanide briquet container above the valve
should be thoroughly dried so that no moisture will reach the cyanide briquets
until the execution begins. The door gasket, the window frames, the Packing
Gland, the Manometer inlet, and the two heart monitor connections are coated
with petroleum jelly as a guard against leakage. Two or more gallons of
distilled water are poured into the system to insure that traps # 1 and
# 2 are full. All chemicals (acid and water as well as caustic soda) are
mixed and readied.
Outlet Valve (4) should be closed to seal the system from the drain,
and Intake Valve (3) should be closed to contain the acid/water mixture
until ready. The Gas Generator Valve (10) should be verifies as closed
and the locking pin installed through the hole in the Gas Valve Lever.
The sodium cyanide briquets should now be placed in the briquet container
above the valve. The Acid should be mixed with warm distilled water and
placed in Acid Mixing Pot (9). Air Intake Valve (2) should be closed. The
Ammonia Injectors should be made ready by closing the Injector Valves and
by pumping up the pressure. The watch-glass of Phenolphthalein solution
is placed on the shelf within the chamber. The doctor tapes the mechanical
stethoscope and the electronic heart monitor to the executee's chest. The
door is closed and sealed.
The doctor verifies that the two heart monitors are working. The Air
Exhaust Valve (5) should be closed and the Exhaust fan should be started.
The vacuum should be monitored on the Manometer (6). Inlet Valve (3) should
be opened allowing the acid/water mixture into the gas generator, and then
closed. The Acid Mixing Pot (9) should be completely filled with tap water
to prevent backflow of gas. The Lethal Chamber is now ready for the execution.
7.004 The Emergency exhaust fans are now verified as operational. A
monitor is stationed at the Manometer. A monitor is at each chamber window,
Air Intake Valve (20, and the chamber door with a hand held gas detector
which sense Hydrogen Cyanide Gas to 10 ppm (parts per million). The emergency
breathing apparatus (air packs) are verified as being immediately available
to those present in the Death House. The execution can now proceed. The
manometer (vacuum) is verbally verified and Air Intake Valve (2) is visually
verified as closed. Additionally, special hydrogen cyanide first-aid kits
are on hand in the Death House, special emergency physician's medical kits
and two resuscitators are on hand at the infirmary, and two emergency ambulances
are on standby inside the prison. The guard tower at the entrance sally
port of the Maximum Security Facility is evacuated as a precaution against
wind carrying the expelled air-gas mixture to the tower and killing the
guard stationed there. This is the only time that this most important security
post is abandoned.
7.005 On command from the Warden, the execution is begun and the witness
curtains opened. The locking pin is now removed from the Gas Valve Lever
and the Gas Valve Lever (1) is thrown, opening the Gas Generator Valve
(10) which drops the cyanide pellets into the acid solution beginning the
generation of the gas. The monitors verify that the vacuum is holding and
that there are no leaks detected. After several minutes, the executee will
be dead and the doctor will verify this fact. The doctor will wait several
more minutes and inform the Warden that the subject is dead. (Total time
normally ten  minutes.) The Warden will then order the chamber to be
cleared of gas and the witness curtains closed.
7.006 The Gas Valve Lever (1) will be returned to closed position which
will close the Gas Generator Valve (10) (which will prevent any further
gas from entering the chamber) and open the Gas Generator Vent Stack Valve
(A) preparing the Gas Generator for draining. The Fan Damper Lever will
be thrown, opening the Air Exhaust Valve (5). The Air Intake Valve (2)
will be opened and the Manifold Ammonia Valve (7) opened. The Chamber will
begin exhausting the air/gas mixture and the ammonia will begin to neutralize
the hydrogen cyanide and protect against any leakage back through the Air
Intake Valve (2). The Chamber will be cleared (according to tests) in one
minute (Eaton says three). This exhaust procedure will continue for fifteen
(15) minutes (at Eaton's instruction) to guarantee at least five full air
Open Outlet Valve (4) allowing the prussic acid residue to pass into
the sewer. Open Inlet Valve (3) allowing water in Acid Mixing Pot (9) to
pass into the plumbing and flush the system while opening Ammonia Injector
Valve (8) to insure no back-flow of poison gas. Pour Caustic Soda solution
into Acid Mixing Pot (9) and flush continuously with tap water for fifteen
minutes or more. Both Ammonia Injectors (Valves 7 and 8) should be turned
off in ten (10) minutes.
7.007 After at least fifteen minutes of venting the chamber, the phenolphthalein
solution should be checked for its characteristic red color, indicating
that the chamber is clear. When the chamber is clear, two operators, wearing
full chemical suits with air-packs and rubber gloves, will open the chamber
and verify with gas detectors. (Previously, gas masks with hydrocyanic
acid and ammonia were utilized.) The operators in the chemical suits ruffle
the executee's hair to eliminate any trapped gas and then spray the executee
and the chamber with ammonia. The doctor, now wearing a chemical suit with
an air-pack, makes the final pronouncement of death.
The executee is now undressed and washed with a caustic soda or ammonia
solution and is removed from the chamber and redressed in different clothing.
His body is then ready for removal by the undertaker, who works on the
body thereafter, with rubber gloves. The clothing worn by the executee
at the time of execution is placed in a plastic bag and sealed, after which
it is disposed of, generally by incineration.
The Gas Generator Valve (10) is now opened by throwing Gas Valve Lever
(1). The Lethal Chamber and all its contents are washed with caustic soda
(walls, floor and ceiling) and the residue flushed into the Gas Generator
at the base of the chamber and thence down the drain. Gas Generator Valve
(10) is then closed by throwing Gas Valve Lever (1) and the plumbing continuously
flushed for another ten (10) minutes. Upon completion of the cleanup, approximately
an hour after the execution ended, the Death House is secured with the
exhaust fan left running.
7.008 The following day, the step-down maintenance is performed. An
inspection is made to determine if everything is dry. The fan is then turned
off. The equipment is then stored in its proper place. All valves are closed
and then opened to half position to eliminate pressure on the packing.
The nuts on the window frames are loosened to eliminate pressure on the
gaskets. The door to the chamber is left open so there is no pressure on
the gasket. The Air Exhaust Valve will not be closed, to eliminate pressure
on the gasket. The Death House is now made permanently secure.
7.009 Prior to the next usage, all valves will be checked, the window
gaskets will be tightened and the Packing Gland will be re-packed. The
Chamber will be again tested to the procedure outlined above.
7.010 The two man Lethal Gas Chambers built by Eaton were identical
in design and construction to the one man chamber at Mississippi except
that they had two seats and duplicate plumbing systems requiring that all
chemical procedures had to be completed twice. Some of these chambers required
that the cyanide pellets (often called "eggs") be placed in a
gauze sack and dipped into the acid solution in the generator below the
chamber by a trip mechanism similar to the one in Mississippi except that
it was suspended from the chain instead of being fastened to the floor.
This was changed because it was safer, in that no one had to handle the
gauze sack after the execution.
7.011 The chemicals used by Mississippi are an approximate 37% Sulfuric
Acid Solution (acid and distilled water) and an approximate 16 ounces of
sodium cyanide. This requires twelve (12) pints of distilled water and
six (6) pints of acid (98%) resulting in 18 pints of dilute sulfuric acid
reacting with 24 briquets of sodium cyanide. This results in two (2) cubic
feet of Hydrogen Cyanide gas at the 10 psi (approximate) operational pressure
or an amount of approximately 7500 ppm.
Continue on to Design Criteria
for a Lethal Gas Chamber
This report is taken from the Zundelsite