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59
Disinfestation.
Disinfestation of furniture, etc., with hydrocyanic acid gas.
In the last annual report there was a detailed description of the steps taken by the council to
prevent the transference of vermin from old bug-infested houses to new housing estates.
The method adopted in the borough is as follows :—Specially constructed steel vans, built to
the specification of Imperial Chemical Industries, Ltd., are used. These are of welded steel with
sliding doors bolted in position, and are fitted with electrical heaters, hydrocyanic acid vaporisers,
and connections to exhaust duct and chimney at the disinfecting station at Wood Lane.
All persons who are allocated flats under the rehousing scheme are notified that fumigation of
all their effects must be carried out before they take up occupation of their new home. At least a
week's notice is given of the date and time of removal. On the appointed day the council's van arrives
at the old house at about 8 a.m., when all furniture and effects which the people decide to have removed
to the new house are loaded on to the vehicle. The van goes to the council's Wood Lane
depot, where all bedding is removed and taken to the steam disinfecting station to be treated by
steam, after which hydrocyanic acid is introduced into the van. The van remains charged with the
gas for two hours, and is then ventilated for at least four hours, after which the contents are chemically
tested for residual gas. As soon as they have been pronounced clear the steamed bedding is loaded
and all effects are taken to the new house.
It has been found desirable, in order to avoid any possibility of accident, to retain all upholstered
articles overnight in a warm, well-ventilated room, and return them to the owners the next day.
During 1935 the disinfestation work has been fairly heavy. One hundred and thirty-eight loads
of furniture from Kensington families were treated at the Wood Lane disinfesting station, and in
addition a good deal of work has been done for neighbouring boroughs (Marylebone, Fulham and
Hammersmith) with whom the council made formal agreements for disinfestation of furniture in
connection with slum-clearance schemes. A charge of three guineas was made to these boroughs
for each load of furniture dealt with. The numbers of loads disinfested under the agreements were—
Marylebone 107, Hammersmith five, and Fulham one. In addition, 11 loads were treated for the
Islington and Finsbury Housing Association.
The Treatment of Verminous Dwellings.
The year's work in fumigating verminous dwellings has been beset with difficulties. Hydrocyanic
acid gas is an unsuitable fumigant for houses, but fumigation with orthodichlorbenzene achieved
a high degree of success.
It was found that orthodichlorbenzene possessed certain advantages which made it a most
useful fumigant. The contact effect of orthodichlorbenzene at all stages of life of the bed-bug is very
great ; the vapour of orthodichlorbenzene kills eggs, nymphs and adult bed-bugs in positions where
no ordinary contact sprays can reach them ; orthodichlorbenzene vapour possesses the remarkable
effect of causing bugs to bolt from their hiding places into the open, and so be killed more quickly.
During the year, however, queries were raised by the government chemist and others as to the
effect of orthodichlorbenzene on operators and persons who inhabit rooms immediately after fumigation
with the substance, with the result that its use has been suspended pending the results of further
research. It may be said here that fumigations with orthodichlorbenzene were a complete success
in Kensington, as may be instanced by the results on one housing estate alone, where vermin infestation
of nearly 70 per cent, was reduced to less than 3 per cent. in 12 months.
Operators employed by the council have always been adequately protected from fumes by gas
masks, and treated premises have generally not been occupied until they have been ventilated for at
least 18 hours.
The council's officers are at present working hard to try to evolve a formula which will enable
the disinfestation of verminous dwellings to be carried out safely and successfully.
The number of verminous premises treated with orthodichlorbenzene, sulphur and other
chemicals during the year was 783, the total number of rooms being 1,181. In addition to this work,
which is carried out by the disinfecting staff, 527 verminous houses were cleansed by landlords in
response to notices served under the London County Council (General Powers) Act, 1922.
The following is a summary of the disinfestation work carried out :—
No. of families whose furniture was removed and treated with
hydrocyanic acid 393
No. of Kensington cases 159
„ St. Marylebone cases 213
„ Hammersmith cases 5
„ Fulham cases 1
„ Islington and Finsbury cases 15
Weight of furniture so treated 269 tons 18 cwt.
Weight of bedding disinfected by steam 24 tons 19 cwt. 1 qr. 24 lb.
No. of articles treated in steam disinfector 5,269
Mattresses and flock beds 932
Bolsters and pillows 1,448
Blankets and sheets 1,267
Sundries 1,662