Tri-orthocresyl phosphate (TOCP) is an organophosphate used as a solvent in industry. It has also been used as an additive for aero engine oil. It causes degeneration of the peripheral nerves (the nerves serving the limbs and hands and feet), a disorder called peripheral neuropathy. This toxic effect is due primarily to a specific interaction between the organophosphate and a particular protein in the nerves, which is an enzyme. TOCP becomes bound to it and then undergoes a change, known as ageing. The reaction with the protein occurs relatively rapidly, probably within an hour of exposure, but the toxic effect, delayed neuropathy, may not be apparent for ten days or more. It seems that the protein, which is attached to the nerve cell, is critical to the function of the nerve, which starts to die after the TOCP binds to it. Thus in the long nerves that serve the legs and arms a process of dying back occurs, which involves degeneration of the nerve and the myelin sheath that surrounds it. The nerve dies progressively, starting at the end and working upwards towards the spinal cord. This degeneration of the nerves means that the muscles of the legs and arms are not stimulated and consequently the poisoned victim suffers paralysis. Post-mortem examination of the victims of the ginger jake episode who died showed inflammation and degeneration of the nerves in the legs.
Why had TOCP been added to the ginger extract? Tri-orthocresyl phosphate was readily available as it was a constituent of lacquers and varnishes, and was extensively used in the leather industry. It was seen as an ideal solvent to use in the preparation of jake because it was odourless, tasteless, colourless, and cheap. It was also miscible with the resinous extract of ginger and soluble in alcohol. Unfortunately, it was very toxic to humans, a fact that appears not to have been known. At the time there was no law requiring food additives or medicinal products to be tested for safety, and thus the suppliers had broken the law, not by supplying a contaminated and unsafe product, but by selling a product that was not as described in the US pharmacopoeia. In June 1930 twenty-one men and six New York corporations were indicted for conspiracy to violate federal laws.
There were at least 35,000 victims in the ginger jake poisoning incident, and some estimates claim that as many as 50,000 people were affected. There seems to have been little sympathy or help for the victims, perhaps because they were thought to be alcoholics or down-and-outs. While the majority of victims were relatively poor, many were ordinary people who were using the preparation for a legitimate purpose. For example, a woman in Boston became a victim after drinking five 2 oz bottles of jake over several days to help her recover from influenza.
There appeared to be considerable variability in the response to the TOCP, with some victims suffering paralysis and even death after only one drink of the contaminated jake. Most of the victims suffered paralysis for a long time, some permanently, and required crutches or sticks to walk, which they did with a shuffling gait, in some cases dragging their feet ('foot drop'). This became popularly known as 'jake leg', and the way victims walked became known as 'the jake walk'.
Although it may not have received much official recognition, the epidemic of ginger jake poisoning passed into popular legend in songs and novels, hence the quotation from the John Steinbeck's novel The Grapes of Wrath at the beginning of this section. At least eleven blues songs referring to the poisoning episode were recorded between i930 and i934, for example:
I went to bed last night, feeling mighty fine
Two o'clock this morning, the Jake Leg went down my spine.
I had the Jake Leg too.
I woke up this morning, I couldn't get out of my bed,
This stuff they call Jake had me nearly dead.
I had the Jake Leg too.
Ray Brothers, 'Got the Jake Leg Too' (1930)
Songs like this were all that remained for the victims, some of whom continued to live for forty more years without compensation or official recognition.22
Since then other occurrences of tri-orthocresyl phosphate poisoning have been documented.23 An incident in the early 1930s in Europe involved the use of apiol (an alcoholic extract derived from parsley seeds), which was adulterated with TOCP for use in inducing abortions, and led to paralysis in several hundred women. Another episode, which occurred in Morocco in i959, has disturbing similarities with the Spanish oil disaster which occurred twenty years later (see below). As in the USA, there was an outbreak of a 'paralysing disease', which was believed to be the result of either a viral infection or poisoning. The symptoms were similar to those described in the ginger jake episode and resulted in an ungainly, high-stepping gait and a weakness in the hands of some victims. The epidemic centred on the city of Meknes in Morocco and affected only the Muslim population, sparing both Europeans and Jews. Among the Muslims, it was generally the poorer people who were affected, and there was a greater incidence in women than in men, and in adults than in children.
These observations seemed to rule out an infectious disease as the cause.
Some victims associated their symptoms with the use of a cooking oil they had bought in local shops and markets. One family were so suspicious of the 'dark oil' they had bought that they fed some of the food cooked in the oil to their dog first. When the dog showed no immediate ill-effects they proceeded to eat the meal themselves. Within a few days, however, both the family and their dog suffered the typical symptoms of aching muscles and paralysis. There was thus suspicion about the oil, and the similarities with symptoms of tri-orthocresyl phosphate poisoning suggested that the oil may have been contaminated. Analysis of the suspect cooking oil and comparison with other cooking oils showed that the 'dark oil' was vegetable oil containing about 3 per cent cresyl phosphates.
The oil was in fact for industrial use, produced to withstand the high temperatures in turbo jet engines, the tri-orthocresyl phosphate being a specific additive. Due to a change in engine design the oil had been discarded, and someone had taken the fateful decision to sell it as cooking oil. At least 2,000 people suffered toxic effects from the contaminated oil, but thankfully there were no deaths. In this case the majority suffered only relatively mild and probably reversible paralysis.
Was this article helpful?
This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.