Poison and Poisoning

Chapter 8

Imagine fearing for your health every day at work. It’s unpleasant, but it’s reality for many people: illnesses, injuries and disabilities can occur in, or because of, conditions in the workplace. These occupational diseases can be the result of work practices themselves, or due to exposure to chemical, physical or biological factors. Legislation has been introduced in an attempt to protect workers, but new hazards are continually appearing.

There are several distinct types of occupational disease: those caused by dust, chemical poisoning, skin diseases, radiation hazards, infectious diseases and occupational injuries. The problem with so many of these workplace hazards is that the true extent of the damage caused may not become apparent until many years later, and sometimes not until many years after the workers have retired.

Non-chemical work hazards can cause blindness, deafness and other problems. Some foundry workers develop cataracts in their eyes due to their prolonged exposure to intense heat in the workplace. They may also suffer from deafness from excessive noise involved in using such equipment. Carpal tunnel syndrome and similar disorders often develop because of repetitive actions or over-use of specific parts of the body; for example, road menders, miners and construction workers all tend to suffer from vibration white finger, the very painful circulatory condition that results from their years of using tools such as pneumatic drills, which also caused deafness too.

Fresh air, fibres and fumes

Dust diseases include pneumoconiosis, which is a fibrosis of the lungs caused by the inhalation of dust. Coal miners commonly suffered from pneumoconiosis as a result of inhaling coal dust. Other workers affected by dust diseases include quartz miners, china clay workers, foundry workers and metal grinders.

Asbestosis was, and still is, a similar work hazard, not only during asbestos mining from the earth, but also at every stage of its transport and processing into finished products. In addition, in both the construction and the demolition industries, workers have to handle asbestos during their work, so they too are in danger of breathing in the fibres and eventually contracting asbestosis many years later.

Yet another dust disease is caused by the inhalation of fungal spores from mouldy hay, straw or grain, and results in allergic alveolitis, also known as Farmer’s Lung. This is an example of an occupational dust disease suffered by agricultural workers.

Many industrial processes involve the use of chemicals, which can cause poisoning of the workers by inhalation or skin absorption. The inhalation of fumes in the workplace can frequently result in lung damage, while the absorption of chemicals into the bloodstream, whether from the lungs or through the skin, can lead to widespread damage involving the liver, kidneys, bone marrow or other organs.

The damage caused by exposure to fumes during metal working varies depending on the toxic agent involved. Cadmium fumes cause kidney damage and fatty degeneration of the heart, while those from beryllium result in lung damage, and there are bone marrow problems from the fumes of lead or organic solvents. There are others that result in liver damage. Life was hard and very dangerous for foundry and mine workers in bygone days.

Allergy, radiation and infection

Many jobs involve physical contact with chemicals, and this can lead to contact dermatitis, due to development of an allergy or irritation caused by those chemicals in direct contact with the skin. If done properly, the regular use of barrier creams, gloves or protective overalls can dramatically decrease this type of risk.

Radiation is a very different type of hazard. The problems here are relevant to those working in the nuclear energy industry, as well as any place where work involves exposure to or handling of radioactive substances. The hazard of radiation also applies to anyone who works outdoors, such as agricultural workers, traffic wardens and market traders. They all need protection from the sun because of the increased risk of skin cancer that their work in the open air causes.

Some workers are even at risk of catching infectious diseases at work. In the woollen textile and carpet industries, workers are at risk of getting anthrax from handling raw wool before it is dyed and woven. Psittacosis, an endemic infection of birds, is a risk to pet shop owners and their employees, safari park staff and zoo keepers as well as the veterinary profession and their staff. Leptospirosis, better known as Weil’s disease, can be caught from rats by sewer workers, miners, dock workers and others who may come into contact with vermin during their work. An example of a newer occupational hazard is the possibility of contracting viral hepatitis and AIDS by those who work with blood and blood products.

A death caused by anthrax occurred in November 2008. The man had been working with hide from West Africa, scraping off the hairs to provide a smooth layer, which was to be used in a bongo drum. He inhaled some anthrax spores and became ill, dying nine days after his admission to hospital. The Department of Environmental Health sealed off his house before giving it a very thorough cleaning. Another bongo player died in 2006 in Scotland. He was believed to have inhaled the lethal anthrax spores while playing his drum. A safer alternative would be to use plastic, instead of skin, for the drum membrane.

Percival Pott, chimney sweeps and cancer

The mining of coal has always been a very dusty job, and many miners ended up with what was commonly known as Black Lung. The doctors, of course, had fancy names for it: Coal Miners Phthisis, or Anthracosis. It was caused by inhalation of coal dust, and while it was not considered life threatening, it did cause catarrhal coughs.

As long ago as the eighteenth century, the surgeon Percival Pott (1714-88) identified Chimney Sweep’s Cancer as an occupational hazard. This cancer of the scrotum was common in chimney sweeps, where contact with the soot in their clothes continually irritated the skin. Another name for exactly the same type of cancer was Gardener’s Cancer, because many gardeners used soot to spread on gardens and allotments. In this case, the occupation was irrelevant as the cause was the soot, which acted as a chronic irritant around the scrotum because of the moisture and humidity of that area of the body.

In 1913, the British Medical Journal published a report about gasworks pitch and cancer. It noted that men handling pitch, or engaged in making briquettes, were occasionally found to suffer from warty growths that could ulcerate and become the seat of an epithelial cancer. These men could also get particles of pitch in their eyes, which could induce severe inflammation of the conjunctiva and cornea, and may even lead to the complete loss of sight. By 1920 it was well known that cancer could be caused in mice simply by painting them with coal tar.

Fibrosis and silicosis

Silicon is generally non-toxic, but silicates can become very dangerous when inhaled as silica dust. In the past, dust inhalation and lung disease were common among workers exposed to silica dust, such as sandstone hand grinders, print workers and those in the boot and shoe trades.

In the 1920s, doctors thought that the presence of silica in the lungs led to fibrosis and predisposed the workers to consumption, which we now call tuberculosis, an infection frequently affecting the chest. They also thought that the predisposition of coal miners, tin miners and gold miners to consumption might also be linked. How right they were: both tuberculosis and dust diseases that damage the lungs would later be recognised as occupational hazards in the mining industries.

Silicosis is now a recognised occupational disorder caused by the inhalation of minute particles of silica, which are to be found today in the lungs of miners, stone-cutters and metal-grinders. This lung condition is one of a group of conditions known as pneumoconiosis, the symptoms of which are wheezing, coughing and shortness of breath. Silicosis can have a latency period of about ten years before the symptoms begin to show themselves.

In Guangdong province, China, an epidemic of silicosis has developed due to the appalling working conditions inside factories that supply the international jewellery trade. The workers, who may work 12-hour days with only one day off each month, labour in factories where windows are sealed and there is minimal ventilation. They don’t even have face masks supplied to protect them from a fog of lethal particles. Those victims who have become ill and received compensation soon find that lawyers’ fees and medical bills leave them destitute. Such industrial disease is just one part of the hidden price of China’s rush to prosperity in the 21st century.

Asbestosis – the delayed killer

Some silicates are fibrous, such as asbestos, a sort of magnesium silicate. Both the dust and fibres of asbestos have been found to be carcinogenic, causing lung damage by inhalation. Asbestosis has a latency period of up to 40 years, but once diagnosed, deterioration is rapid, often resulting in death within a year or so.

Asbestos was used for many years as a building material and in brake linings. However, extensive legislation and litigation in the Western world in the latter part of the twentieth century have now led to use of alternative materials, although asbestos is still widely used elsewhere in the world.

Companies have been bankrupted by lawsuits from asbestos-related claims for compensation from victims. In the UK, many employers and their insurers have delayed paying compensation by prolonging legal actions. Many asbestosis victims have died waiting.

Mesothelioma is a specific type of cancer of the pleura, the membrane that lines the chest cavity and covers the lungs. This cancer has about a 90 per cent increased incidence among those exposed to asbestos. It is even affecting the children of workers, although not until they are middle-aged themselves. They contracted this devastating illness from the dust that remained on their parents’ clothes when they returned home from work. Once diagnosed with mesothelioma the average life expectancy is just 18 months.

Fatal solvent fumes

Carbon disulphide is a liquid that gives off foul-smelling fumes. The fumes are toxic by inhalation, by ingestion and even by absorption through the skin. The poisoning is cumulative, and a concentration of only one part in 3,000 parts of air is sufficient to produce a headache after only a few hours of exposure. The continued inhalation of small quantities of the vapour over many weeks or months can lead to chronic effects.

In the 1930s, the female workers in a rayon factory in the USA who were exposed to the fumes of carbon disulphide developed menstrual disturbances, and workers of both sexes were found, over a period of time, to have an increased mortality due to cardiovascular disease. Sexual impotence was also found to be a common symptom among the exposed male workers.

Carbon tetrachloride is used in industry as a solvent and degreaser, and it was formerly used in some types of fire extinguishers and for dry cleaning. However, these uses have been phased out as carbon tetrachloride was found to be readily absorbed by inhalation as well as through the skin and was shown to be carcinogenic in animals. Safer solvents are now used in the workplace and for dry cleaning.

Benzene, an industrial solvent, has caused poisoning and death. During the 1930s there were nine cases of poisoning, including three deaths among the female workers in a Belgian mirror factory. The women were employed to varnish the mirrors after they were silvered. The second protective coat of varnish applied after silvering was a solution of gum-resin dissolved in benzene. After a time, the women were found to be wasting away, with severe aplastic anaemia. This turned out to be directly due to the effects of the benzene used as the solvent in the varnish they were using.

Also in the 1930s, factory workers making mothballs and lavatory deodorant discs, which contained naphthalene, were liable to contract acne following exposure to the naphthalene fumes. Some workers even went on to develop systemic poisoning, starting with digestive disturbances, profuse perspiration, blood in the urine and finally death due to liver failure.

Tri-nitro-toluene (TNT) is an explosive used in World War I. In 1916 the British Medical Journal reported that the Ministry of Munitions had had some 50 cases of fatal toxic jaundice out of the thousands of workers, mainly women, who were engaged in the making of munitions for the war. The symptoms of TNT poisoning included dermatitis, digestive problems, blood changes and jaundice.

Purest is not the safest

Breathing pure oxygen below a depth of ten metres, divers can suffer convulsions and death. In the past, several divers died by drowning in this way before the cause of the problem was realised and dealt with. Today divers breathe air with an enriched oxygen content instead of pure oxygen.

Deep-sea divers, such as those working on the North Sea oil rigs, can suffer from nitrogen narcosis, known as the bends. This can occur when nitrogen, which makes up 79 per cent of air and so is contained in the tank of compressed air, is breathed in under high pressure. It dissolves in the blood and in the lipids in the circulation, but then becomes a problem if the diver returns to the surface too rapidly. If the decompression during the return to the surface after the dive is too fast, then nitrogen gas bubbles can form in the blood, producing gas emboli and decompression sickness, which can be very painful and life threatening. Treatment of this condition includes the use of a decompression chamber in which divers can be very slowly returned to normal atmospheric pressure, which in severe cases may take several days.

Gas at work

When seven chemical workers were exposed to chlorine gas in 1969, their exposure times lasted from as little as three minutes to as long as 45 minutes. The symptoms they suffered included chest pains, choking sensations, coughs, headaches and muscle pains. These effects lasted from three to nine days. There was respiratory failure in three of the workers and hypoxaemia in four of them, which was treated with oxygen therapy. Fortunately they all survived.

In addition to dust diseases such as pneumoconiosis, coal miners were also at risk from explosive mixtures of air and methane gas, which they called firedamp. They used to take small finches such as canaries, in cages, down the mine with them, as an early warning system for the presence of gas. If the canary fell off its perch, they knew they had to get out of that part of the mine.

Methane gas is the chief constituent of natural gas derived from oil, which we use in our homes today for cooking and heating. In the past, methane was also called marsh gas. Produced during the decay of vegetable matter, methane can be a problem at landfill sites, unless precautions are taken to safely vent any gas produced by all that rotting rubbish.

Sulphur dioxide is a colourless, non-inflammable gas with a suffocating smell. Inhalation of high concentrations, as may happen within the workplace, can inhibit respiration and even cause death by asphyxia, while lower concentrations are irritant to the respiratory tract and to the eyes. When 230 workers at a copper smelting plant were exposed to high levels of sulphur dioxide about 30 years ago, 190 of them were later found to have liver damage and 168 also had blood abnormalities.

Radioactive radium

The dangers of exposure to radiation were not fully appreciated for many years. Radium was discovered in 1898 by Marie Curie and her husband Pierre. The pure metal itself was not isolated until 1911 when Marie Curie and her assistant managed to isolate it by electrolysis. She later went on to discover two more elements and was awarded two Nobel Prizes for her work. She spent her life working with radioactive chemicals, and in 1934 Marie Curie died of leukaemia, caused by overexposure to the radioactive radiation. Her laboratory workbooks are still so radioactive that even today they need to be kept in a lead-lined safe.

Due to its radioactivity, radium glows in the dark, a property that was quickly utilised at the start of the twentieth century to make luminous paint. Workers used this luminous paint to paint the faces of clocks and watches. Unfortunately, many of these workers, who were mainly women and young girls, had a habit of licking their brushes in order to get a fine point. Contact with radium causes ulceration of the skin, so it did not take very long before many had developed cancerous growths, particularly on the mouth and jaw. Some workers became so contaminated that they even glowed in the dark themselves.

Phossy jaw and other problems

Phosphorus exists in three forms: white, red and black. The white form is the most common, and glows in the dark. It also spontaneously combusts in air and is a deadly poison.

Phosphorus initially became an occupational hazard in the match industry. Its dangers were first mentioned in the medical literature in 1838, and the first British case came to the attention of the medical profession in 1846.

In the match industry, workers who breathed in phosphorus vapour over a period of time developed ‘phossy jaw’, which slowly eats away the jaw bone. This happened to many workers in this industry in the nineteenth century, when phosphorus was used to make the match heads. Workers found that their teeth fell out as their jawbones crumbled, the pain was excruciating and their mouths ran with pus from the infected areas of their gums. Many children were affected too, as they were widely employed in the match industry at that time, purely because they were the cheapest labour available.

Legislation was eventually introduced, with the Children’s Employment Commission of 1863 which led to the Factory Acts Extension Act in 1864. This latter act brought dangerous trades within the scope of the existing Factory Acts, and these laid down a minimum age of employment and hours of work. These changes to the legislation prevented any further use of children. So the match industry began to use more young women instead, who were the next cheapest source.

In 1898, there was a government report on the use of phosphorus in the manufacture of lucifer matches, the first type of phosphorus-containing match. The use of white phosphorus was eventually outlawed following a special international meeting – the Berne Convention – in 1906. A British law was duly passed in 1908 and the lucifer was outlawed. Even so the new law did not come into effect until the end of 1910.

As usual Britain was somewhat late in the day with this legislation, as Finland had outlawed lucifers as long before as 1872, and most other European countries had done the same in the intervening years. But the manufacturers finally began to use a phosphorus sulphide instead of elemental phosphorus. The necrosis known as ‘phossy jaw’ completely disappeared as an occupational disease in the match industry.

Inhaling metal fumes

Cadmium is used to prevent rust. It is used as a coating applied to metal, but during the welding process, fumes of cadmium are produced. These fumes can cause symptoms of delayed respiratory distress, which may not appear until some four to ten hours later. Long-term kidney damage has also been found. Cadmium tends to accumulate in the body, particularly in the liver and kidneys. Deaths have occurred due to the inhalation of cadmium fumes.

In 1971, a man died after brazing some metal using solder which contained about 25 per cent cadmium. Five years later another man died in similar circumstances. A few years after these deaths, an investigation of 27 coppersmiths, who had all been exposed to cadmium fumes during their work, revealed an association between cadmium exposure and liver impairment, kidney stones and restrictive airways disease.

Manganese is another metal that can be an industrial hazard by inhalation. Workers breathing in the fumes from hot manganese can suffer from ‘fume fever’ which causes fatigue, anorexia and impotence.

In the 1930s, there was a report of four cases of chronic manganese poisoning in men who were all employed at the same manganese works. The symptoms appeared in one case after only eight months of work and in the other three men after 2½, 6½ and 8 years respectively. The men appeared to exhibit Parkinsonism. Their symptoms included involuntary laughing and crying, aggression, delusions and hallucinations, all of which have affected manganese miners in the past. This syndrome used to be called ‘manganese madness’, but with modern health and safety legislation, such cases are now rare.

Zinc metal is irritant to the skin, and breathing in the fumes of hot zinc also causes fume fever with a sore throat, cough and sweating. Brassfounder’s Ague was a disease which had similar symptoms, due to the zinc oxide fumes which are given off when the molten brass, an alloy of zinc and copper, is poured into moulds.

In the 1960s, a soldier died following inhalation of zinc chloride smoke in a confined space during a civil defence exercise. He had severe chest pains and became cyanosed. After 24 hours his condition worsened and he eventually died 11 days after his exposure to the fumes. The post-mortem showed severe lung damage and extensive necrosis of the affected tissues.

Copper is a metal that is quite soft and easily worked at room temperature. As with cadmium and zinc, copper workers can also suffer from fume fever, when working with the hot metal or even with alloys containing copper. Copper dust can also be inhaled, giving rise to chest pain. In the 1970s, vineyard workers who used copper sulphate solution, which is blue in colour, in sprays were found to have blue spots on their lungs and many other lesions, which all contained particles of copper.

Beryllium is a metal that mimics magnesium in the body and even displaces magnesium from certain key enzymes, causing them to malfunction. Beryllium itself has no use at all in the human body, and the lungs are particularly sensitive to poisoning from it. Beryllium is used in alloys, as a light structural material, and is also used in ceramics and in nuclear reactors. Beryllium, whether as fumes or dust, is an industrial hazard because it causes chronic lung inflammation and shortness of breath. These symptoms are of a serious condition called berylliosis, which can result from either brief heavy exposure or long-term, low-level exposure. This disabling condition is permanent and about one third of such patients die as a result, while others get lung cancer.

Nickel dust causes both nasal and lung cancer, and the gas nickel carbonyl can be lethal, even in tiny amounts. Nickel, even when used in stainless steel, can cause dermatitis, starting with the so-called ‘nickel itch’ caused by the acids in sweat reacting with the nickel in the stainless steel which is in contact with the skin. Watches, jewellery, spectacle frames and garment fasteners can all cause this problem, which can be solved very easily, by painting the offending metal surface with clear nail varnish, which then provides a barrier between the skin and the metal.

Vapours and amalgams

The hazards of handling mercury were known 2,000 years ago. Mercury is a metal that is liquid at room temperature, and so can easily vaporise. The mercury vapour produced can be inhaled and cause poisoning via the lungs. The Romans would only use convicts and slaves to work in their mines, as they knew of the poisonous nature of the mercury within. In 1665 one of the first labour laws made it illegal for miners to work more than six hours a day in the mercury mines of what is now Yugoslavia.

In 1810 a troopship, HMS Triumph, was transporting flasks of mercury from Spain to London. During a storm one of the flasks broke open, releasing the liquid mercury. The mercury ran about the ship, lodging in nooks and crannies in the decks, and affected all 200 members of the crew, who breathed in mercury vapour for the remainder of the voyage. Three of the crew died, and so did all the cattle and birds that were also on board.

Barometer Maker’s Disease had the same cause: breathing in mercury vapour, which in this case came from filling the barometers with liquid mercury. In the hat industry, in order to turn beaver and rabbit fur into felt, the pelts were dipped into a solution of mercury nitrate and then dried. Workers often suffered from ‘hatter’s shakes’ and ‘mercury madness’, and it is from this industry that we derive the phrase ‘mad as a hatter’.

Mercury can form amalgams with other metals. Some of these are solid, such as dental amalgam used in tooth fillings, which are a type of metal alloy. Others, which are mercury rich, are liquid, like pure mercury itself. The application of heat to these liquid amalgams results in the mercury vaporising, leaving the other metal behind applied to a surface, as in gilding.

In Birmingham in the early nineteenth century, workers gilded buttons using a gold/mercury amalgam, with one gram of gold being sufficient to gild 500 buttons. When heated, the mercury was given off as fumes, poisoning the workers, who were said to suffer from ‘gilder’s palsy’. This poisoning affected those living in houses nearby as well and only stopped after 1840, when a new process – electroplating – arrived.

Electroplating was more efficient and economical, as it would gild even more buttons for each gram of gold used. The Royal Navy, however, continued with the mercury amalgam method for another 100 years because the gilding produced by this method was more durable, so the naval gilders continued to suffer gilder’s palsy.

In Russia, in the early nineteenth century, over 60 workmen died during the gilding of the dome of St Isaac’s Cathedral in St Petersburg, Russia. This massive task involved about 100kg of gold being applied to copper sheets, using the gold/mercury amalgam method. The finished golden dome was magnificent, but not without a disastrous effect on the workforce.

Until the middle of the nineteenth century, mirrors were always made using silver amalgam, so mirror-makers were another group who suffered from mercury poisoning, until the chemist Liebig improved their lot. He showed that, to make a mirror, a film of silver could be deposited on glass by chemical means, without the use of mercury.

Even in the mid twentieth century, mercury was an occupational hazard. For example, police detectives searching for fingerprints at crime scenes used a dusting powder made by grinding chalk and mercury together. Of course, many officers began to display the symptoms of chronic mercury poisoning. A safer alternative is now used.

In the past, mercury has had a wide range of uses in industry – in plating, felting, dyeing and tanning – where it has now been replaced by less harmful substances. Its long-time use in thermometers and barometers has also now largely been replaced, although it is still used in some electrical switchgear. Most batteries no longer contain mercury either, with the exception of hearing-aid batteries. With these, mercury is still used because this type of battery will continue working well until discharged, unlike other types of battery which tend to fade over a period of time.

Lead colic

Lead is another heavy metal, and a cumulative poison, for which our bodies have no practical use at all. In the past, lead was a major occupational hazard in the workplace, but it is now closely controlled by health and safety legislation.

Plumbers, who in the past worked with lead, tended to suffer from an excess of this substance, which caused poisoning, medically referred to as plumbism. The very name plumber is taken from the Latin word for lead, ‘Plumbum’, because since ancient times this soft and easily worked metal was used to make pipes and storage vessels for water and other liquids. Lead poisoning produced a characteristic blue line on the gums at the roots of the teeth, together with abdominal pain, constipation and nausea. Painter’s Colic had these same symptoms, caused by the lead used to make paint in bygone days.

In the past, because lead was so widely used, there were many cases of lead poisoning in the workplace. In 1900, for example, there were 1,317 recorded deaths due to lead poisoning. Over the years there have been many reports of poisoning by inhalation of fumes containing lead from a wide variety of causes. Burning battery cases of lead/acid batteries, using an oxy-acetylene torch to cut lead-painted steel, print shop workers burning newsprint... These are just a few examples.

Even yarn workers in the textile industry developed lead poisoning from some of the dyestuffs used to dye their yarn. Pottery workers used lead glazes for their pottery, but the glaze arrived as a powder which had to be made up into a liquid glaze by stirring it into water. It was the dust released during the storage and manufacture into glaze which resulted in poisoning by inhalation of the lead-laden dust. Even the children of pottery workers suffered from lead poisoning as a result of the powder clinging to their parents’ clothes.

More metals

Those who work with cobalt salts tend to suffer from a form of dermatitis. Cobalt blue is a pigment widely used by artists and craft workers in porcelain, pottery, stained glass, enamelling, jewellery and tile making. Such workers are all at risk of developing dermatitis, and, in the longer term, of developing cardiomyopathy due to exposure to cobalt.

Chrome ulcers are an occupational skin problem for metal workers using this metal and will be mentioned again in Chapter 20. Destruction of the nasal septum is fortunately now rare in these workers, but the inhalation of dust containing chromium compounds may also cause severe lung damage and inflammation of the eyes. Stomach ulcers can also occur and there is a possibility that chromium compounds may be carcinogenic.

Platinum is a metal not essential to life, but as it is non-toxic it can be used in implants, which the body will tolerate. Certain platinum compounds, however, are poisonous and some are even used to treat cancer. People in regular contact with platinum compounds, such as jewellers, laboratory glassware workers and those involved in making electrical contacts or catalysts, may suffer from an allergic reaction, a condition called platinosis, exhibiting symptoms similar to asthma and the common cold.

Powerful occupational poisons

Nicotine is a toxic alkaloid derived from tobacco, which was used as an insecticide. It is a powerful poison, even when just applied to the skin. In 1933, the British Medical Journal reported the case of a girl who worked in an insecticide factory. She collapsed following the accidental spillage of a small quantity of a 95 per cent solution of nicotine onto the sleeve of her overall. Her life was saved by giving her emetics and by scrubbing her skin with soap and cold water, as hot water would have increased the skin absorption of the nicotine.

In America at about the same time, a florist was also accidentally poisoned when a solution containing 40 per cent nicotine was spilt on her clothes. She suffered nausea, vomiting, sweating and difficulty in breathing, and it took her three weeks to completely recover.

Paraphenylenediamine hair dyes and similar types of dye have been used not only to dye human hair, but also to dye fur in the fashion industry. A contact dermatitis, which may produce eczema, nervous symptoms, dizziness, weakness and even impairment of vision, were all symptoms suffered by those working with this type of dye.

A 21-year-old hairdresser’s assistant died of liver failure in the 1930s following poisoning by hair dye, even though she had worn rubber gloves when applying the dye. Fur workers also suffered from dermatitis and even those wealthy enough to purchase the fur products developed a fur dermatitis following contact with the dyed fur when they wore it.

Ricin is an extremely toxic substance present in castor beans, from which castor oil is obtained. Even chewing a single raw castor bean is sufficient to cause poisoning. Ricin is a protein and so, fortunately, can be made harmless by heating. Castor beans are crushed to extract the oil, and the resulting seed cake, or pomace, is then treated with steam to destroy the poisonous ricin. However, sometimes the heat treatment is delayed or omitted. Ricin poisoning has even occurred in port workers who handled cargoes of castor pomace which had not been heat treated before dispatch.

And finally, improvers and Baker’s Itch

In the early twentieth century, chemicals such as potassium persulphate, called ‘improvers’, enabled millers to use a larger proportion of cheap wheats when making flour. They also allowed the bakers to introduce more water into the dough and therefore into the finished loaf of bread. It was claimed that the ‘improvers’ made the yeast work better by making the conditions in the dough more acid, enabling the British miller to compete with overseas competitors.

Baker’s Eczema and Baker’s Itch were two industrial medical conditions both attributed to the use of flour containing a small amount of ‘improver’, just 63 parts per million of potassium persulphate. In the 1920s such chemicals were in use in Great Britain and came to be a known occupational hazard to British bakers. This problem was not seen in either French or American bakers, as ‘improvers’ were illegal in France and America, and indeed these chemical hazards were unknown in this country before the introduction of ‘improvers’.

Poison at work threatens a wide range of people, from the industry workers mentioned in this chapter to the farmers in the next.