Part III - Historical Survey of the Porton Down Service Volunteer ...

minutes later one of the rabbits died. The experiment was brought to an abrupt end and the
men quickly washed off the substance from their arms.
On 14 April 1945, a meeting of the three UK Services was convened at which it was decided
that defensive measures against the new gas were to be developed urgently [12]. The
foundation of the Services' concern was that Germany might yet use the artillery shells
against the Allies as more shells had been found at Espelkamp [13]. Telegrams [14] from the
War Office to the Headquarters of Allied Commands were sent on 16 April, containing
preliminary information about GA [15], including:
GA "is not a vesicant but is rapidly toxic if the eye or skin absorbs liquid - lethal dose
for man of the order of 5 grams absorbed through skin. Vapour in low concentrations
strongly constricts pupils and causes tightness of chest. Mainly dangerous in the
field to eyes and lungs as an initial cloud".
The assessment of GA continued after these telegrams were sent. Studies with animals and
humans were conducted: on 18 April 1945 fifteen men, including Porton staff, were exposed
to GA at levels of 3.2 mg.min/m 3 and 14 mg.min/m 3 (t = 2 mins) [15, 16]. The main results
were:
• pupils were constricted (miosis) by the lower dose, and this persisted for 48
hours;
• although all observers detected a faint smell at the higher dose, it was thought
that the concentration (7mg/m 3 ) could not be reliably detected on the battlefield.
At the higher dose all human subjects had "markedly constricted pupils" followed
by a severe headache. These symptoms lasted for 2 days.
PF-3 was known to cause miosis but exposures of between 40 and 80 mg.min/m 3 of PF-3
were required to induce the same effects as the much lower doses of GA used here. It was
thought important, therefore, to explore miosis further and find out if it affected military
efficiency [15].
The study in July 1945 involved 42 Service volunteers. Seven men were exposed twice.
Some men wore no protection during the study and were exposed to GA at 0.7-21 mg.min/m 3
(t = 10 mins). Some men had their lungs protected by an oro-nasal respirator and were
exposed to 30 mg.min/m 3 (t = 10 mins). The main results were as follows [17]:
• the exposure to 0.7 mg.min/m 3 induced coughing and the feeling of constriction
of the chest;
• exposures to 14, 18 and 21 mg.min/m 3 had a "severe harassing effect"
characterised by some or all of the following symptoms: severe headache,
pinpoint constriction of the pupils, pain when focusing on objects close to the eye,
slight blurring in vision, tightness in the chest and coughing, nausea and
vomiting. Without treatment, these symptoms became most debilitating 24-48
hours after exposure;
• 30 mg.min/m 3 exposed only to one eye decreased visual acuity markedly, and
recovery was not complete until at least 17 days later.
This work suggested that exposures to GA of greater than 14 mg.min/m 3 would impair military
efficiency and, therefore, might be regarded as harassing doses [18] but no studies had
explicitly assessed the ability of the men exposed to GA to conduct military tasks. The next
study [18] sought to remedy that.
Later in July 1945, infantrymen and civilian staff working at Porton were exposed to GA at
28 mg.min/m 3 (t = 10 mins) and then asked to perform tasks that were part of their normal
duties. Twenty nine people participated in this trial. For the infantrymen, the tasks included
standard tests of elementary infantry training (rifle firing on the range and the operation of a
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