850 PCBs AND ASSOCIATED AROMATICS
Also: Jensen, S. and G. Widmark: OECD pesticide confer-
ence report on unintended residues in the environment.1968Risebrough et al. (1968) published in Nature: “Polychlori-
nated Biphenyls in the Global Ecosystem”. Found that the
eggshell thickness of fragments of a peregrine falcon egg
was 34% less than the thickness of eggshells present in the
same area 21 years previously.
September, 1968: Information sent by Westinghouse on
“Inerteen and Environmental Contamination” described that
“It has been indicated by several laboratories that measurable
amounts of the PCBs are present in our general environment
and may have some effect on certain species of wildlife. While
askarels are generally regarded as being non-toxic to humans,
it is reasonable to assume that very high standards of con-
trol will be issued by the Government in the overall program
against pollution”. The bulletin indicated that Monsanto had
arranged for return of scrap Inerteen fluid in sealed drums and
indicated that “Inerteen soaked coils, insulation scrap, filter
cartridges, and other materials must be stored until appropri-
ate methods can be provided to dispose of them properly.”
In October 1968, Japanese health officials became aware
of an epidemic disease which came to be known as “Yusho”.
The cause of the disease was the ingestion of PCB
contaminated rice oil over a period of about eight months
[Kuratsune et al., 1972]. The epidemic became the subject
of a special issue of the journal Fukuoka Acta Medica in
June 1969 [Kuratsune et al., 1969]. The incident is impor-
tant because it clearly documents the potential for reproduc-
tive and transplacental effects in humans.
About 325 patients with acneiform eruptions had been
treated in northern Japan between the summer of 1968 and
January 1969. The apparent cause of the poisoning was traced
to the consumption of a particular brand of rice bran oil.
By May 1970 the total number of cases had risen to
1,291. The common symptoms included acneiform erup-
tions, hyperpigmentation of the skin, nails and mucous
membranes, swelling of the upper eyelids, and hyperemia of
the conjunctivae.
The ‘Yusho’ incident and another very similar accident
in Taiwan, known as the ‘Yu-Cheng’ incident, are fully dis-
cussed in a later section.
The Yusho incident prompted the US Food and Drug
Administration to initiate a national survey to determine the
extent and levels to which PCBs might have made their way
into the food chain.1969Analytical methods for the detection of PCBs in food became
recognised as routine by the Food and Drug Administration
(FDA).
Kuratsune et al. (1969) published an article entitled
“Study on ‘Yusho’ or Chlorobiphenyls Poisoning”.
Among the women with Yusho who were pregnant at the
time of the outbreak, some were examined for observationsthat might indicate reproductive effects upon human
exposure to PCBs. Since these case reports are based upon
a small sample of Yusho cases, there observations cannot be
verified statistically and are therefore only indicators that
PCBs in rice oil might result in some reproductive effects
that are not inconsistent with those reported in laboratory
studies. Out of nine pregnant women, all of whom had char-
acteristic Yusho poisoning, two incidents of stillbirth were
reported in which the fetuses manifested Yusho symptoms
such as brown staining of skin, nails and gingive [Taki et al.,
1969].
February 24, the San Francisco Chronicle carried a major
feature about “a menacing new pollutant” in marine life
research carried out by Dr. Robert Risebrough of the University
of California.
March 3, 1969: Information on the San Francisco
Chronicle’s article is circulated to Monsanto customers in a
letter dated March 3, 1969.
On March 7, 1969 the Associate Commissioner for
Science and Deputy Associate commissioner for Compliance
asked the Bureau of Science to evaluate foods sampled for
pesticides for evidence of PCBs. None was indicated using
the analytical methods of that time except for traces of
PCB in fish from the Great Lakes.
March 10–14, 1969: District pesticide experts were given
analytical information concerning PCB and told to be aware
of the possibility of its presence in foods. (Pesticide Analytical
Workshop 3/10–14/69).
PCB was identified as a contaminant of many of the fish
analyzed as part of proceedings against the City Smoke Fish
Co. of Detroit, MI (June and July 1969). The fish also con-
tained DDT above 5 ppm.
July 1969: Cow’s milk was found to be contaminated
with PCBs (July 1969) from cows given feed treated with
herbicides that had been diluted with PCBs.
On September 13, 1969 the Baltimore District Office of
the FDA reported PCB in West Virginia milk. The source
was traced to the use of an Aroclor as a solvent for pesticide
spray.
Regulatory action at 0.2 ppm PCB on a whole milk basis
was established by the FDA on December 16, 1969.1970Aroclor 1260 was discontinued in 1970. 1254 was an avail-
able alternative.
Monsanto, the only producer of PCBs in the US alerted
its customers to the potential problem of environmental con-
tamination. Major electrical equipment manufacturers were
requested to relay the information to end-use customers with
advice as to proper destruction of PCBs. Monsanto advised
clients from 1970 onwards to be careful not to let water that
may contain PCBs get into sumps or drains that would lead
into the sewer system.
In 1970, the FDA prepared a summary of the available
information on the chemistry and toxicity of PCBs. [US Dept.
of Health, Education, and Welfare (1970): “Supplement 1—
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