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Between 1976 and 2000, more than 50,000 villagers of Kasargod district in Kerala, India have been exposed to endosulfan, a persistent organic pesticide, sprayed on the cashew plantations owned by the Plantation Corporation of Kerala. More than 3000 people living near, downstream and downwind of the estate were affected by debilitating rare diseases like mental retardation, cerebral palsy, cancer etc. In response to the peoples’ agitation, the National Human Rights Commission (NHRC) mandated the National Institute of Occupational Health (NIOH) to investigate the issue in 2001. NIOH observed that “aerial exposure” to endosulfan was responsible for delay in sexual maturity among the adolescents. In the final report submitted to NHRC and the Ministry of Agriculture, Government of India, NHRC categorically stated that they did not see any serious diseases like cancer or mental retardation in the villages they went. They recommended a detailed epidemiological study and long term monitoring for cancers of the endocrine system in the affected villages. This study has not been initiated so far. Aerial spraying of endosulfan has been banned since 2000. The claim for compensation by the victims has not been settled so far. The state government has been providing some monetary relief, out of budgetary allocation. A public interest litigation seeking a final decision on the compensation and free medical treatment of the affected people is pending in the High Court of Kerala. NHRC, the Government of Kerala, the anti-POP activists and victims support groups and large sections of the local media believe that the link between endosulfan exposure and the epidemic unfolding in Kasargod villages has been established. In the absence of a detailed epidemiological study, the cases for compensation of the victims and for a permanent ban of the molecule will be


During 1976-2000, the Plantation Corporation of Kerala flew some 65 sorties and aerially sprayed endosulfan, a persistent organic pollutant (POP) over an area of about 12000 acres in nine villages in Kasargod district. This was to eradicate tea mosquitoes in the cashew plantations. The people living inside the plantations and downwind and downstream of the experiment were exposed to this hazardous chemical for 25 years. Studies conducted after the ban of the pesticide show significantly higher concentration of endosulfan products in environmental media like water, soil and lake sediments and human blood, even in a village 25 km away from the sprayed area. The government of Kerala banned Endosulfan in Kerala in 2001. The Central government has banned its aerial spray. This POP is still being applied widely India and is also available in Kerala.

The Exposure Pathways

All the environmental media studied have been contaminated with endosulfan. The main routes of entry into the human body are:

  1. From mother’s body to foetus via placenta– 36 weeks – Placental Exposure
  2. From mother’s milk to baby – 36 months – Maternal Milk-borne exposure
  3. From locally grown plant and animal foods – egg, milk and meat – chronic, perennial – Food borne exposure
  4. From water – Chronic and perennial – Water borne Exposure
  5. From air through breathing and through skin – Few hours till the vapour remains suspended in air. – short duration. – Aerial Exposure

Those who are exposed through the first three pathways, will also be exposed to metabolites – stress chemicals – that are generated by the living systems in response to the exposure. Cattles with congenital anomalies and cancers are more likely to be sold for slaughter.

The exposed communities are :

  1. Living inside the plantations – about 300 families
  2. Living very close to the plantation – > 2000 families
  3. Living downstream and downwind from the spray site – not estimated
  4. Workers who were handling the pesticide and spraying equipments – about 300


Chronic exposure through water and food appears to be the major pathway. The exposed people may be living very far away from the scene of spray. NIOH study found endosulfan in soil samples of a village, some 25 km away from the sprayed village. The mode of transport in this case was few first order streams that originated from the sprayed village.

Some people have been exposed through all four pathways and they will be in the high dose category. According to PCK, there were 292 houses inside the plantation and 2026 household outside the plantation. Estimated number of people living in these houses is 1548 inside the plantation and 10,738 in the latter. This means that PCK considers an area within about 300 meters from the boundary of the plantations as exposed. The extent of aerial exposure will be a function of direction and speed of wind and the duration of suspension of endosulfan in air. This group has been exposed through all the pathways listed above and can hence be considered as the highly exposed group.

People exposed through other pathways will be much larger than those directly under the cloud. It will be difficult to estimate their number also. Unlike in the case of aerial exposure, distance from the plantation may not be a good indicator of the concentration in water. As a rule, soil, water and sediments in valleys will be higher than that in the foothills.

Table 1
Division Area Inside Plantation Outside plantation
Ha Houses People Wells Houses People Wells
Kasargod 2190 210 1113 174 1593 8443 1333
Rajapuram 1526 36 191 3 225 1193 18
Cheemeni 980 46 244 46 208 1102 208
Total 4696 292 1548 223 2026 10738 1559
Dr.P.K.Sivaraman Additional Director of Health Services (PH)
Report of the Expert Committee,
Government of Kerala, PAGE 12



Environmental Samples – soil, water, sediments, cashew leaves – these are indices of contaminations. Centre for Science and Environment, Kerala Agricultural University and the National Institute of Occupational Health conducted these studies. This part of research can be considered as more or less complete.

Biological Samples- Analysis of human blood samples – CSE and NIOH studies showed positive results even after two years of ban on aerial spray. Study of human blood samples for concentration of endosulfan and levels of hormones of thyroid, growth and reproduction. CSE and NIOH have done fairly elaborate studies. In the legal framework of the day, the victims’ claims for compensation will have to be supported by epidemiological evidences.

Epidemiological Study. An epidemiological study compares the disease burden or incidence of selected diseases, abnormalities two or more population groups. The first of the two populations is known as the study population. The exposure can be to an agent in environment, a microbe, a chemical (endosulfan, tobacco smoke), heavy metals like cadmium or a physical agent like ionizing and non-ionizing radiation. The community can be living in a compact area, as was the case with Bhopal, or may be families of workers living in different places, or any other group like students in an institution. In situation where good and reliable local or regional health statistics are available, the rates found in the study population can be compared with that. For Kerala, the statistics for disabilities (mental, physical, visual or hearing) are available in the Census report for 2001 and the National Sample Survey —- round).

In the case of most of the diseases in PCK impacted villages, reliable local or state level data is not available. Here, the rate of diseases observed in the study population has to be compared with the rates in another (control) population that is not exposed to the agent under consideration. Both the populations should be comparable in terms of sex and age structure, ethnicity, food habits, life styles, social class etc. If the exposed population is very large, the first study can be on a smaller sample. Here again, the sample should be comparable with the larger exposed population.


Only one health study, conducted by the National Institute of Occupational Health (NIOH) Ahmedabad, as mandated by the National Human Rights Commission (NHRC), has been published in a peer-reviewed journal. NHRC and all the pro-victims campaigners assert that through this study, NIOH has proven the link between endosulfan and the epidemics in PCK villages. According to the Endosulfan Victims Relief and Rehabilitation Cell’s website:


As early as 1979, stunted growth and deformed limbs were noticed among new born calves. By 1990s health disorders of very serious nature among the human population came to the lime light. Children were found to be the worst affected with congenital anomalies, mental retardation, physical deformities, cerebral palsy, epilepsy, hydrocephalus etc. Men and women were also affected with various chronic ailments, many irreversible and difficult to treat. There is a high incidence of disorders of the central nerves system, Cancer and reproductive disorders. The National Institute Occupational Health (Indian Council of Medical Research) says that after studying various aetiological factors responsible for health problem was aerial spraying of Endosulfan.” www.endosulfanvictims.org.


The NIOH study did establish that “aerial exposure” to high doses (of) endosulfan was the aetiological factor responsible” for the anomalies they observed. Aerial spraying is not aerial exposure. Majority of the exposed people and the victims lived far away from the sprayed area and were not subjected to aerial exposure. And the anomalies listed by the campaigners and the health problems reported in NIOH study were different. NIOH study suffers from two serious design defects, which are being discussed below.

NIOH Study

NIOH “study was scientifically planned, designed, and carried out by a team of experts, which included epidemiologists, physicians, pediatricians, medical toxicologists, statisticians, analytical chemists, and biochemists, who have years of experience in conducting such studies and have many publications to their credit.” The subjects of the study were students of two schools – one located in village Padre and the other in village Meenja. Endosulfan was aerially sprayed over Padre and not in Meenja. Environmental samples like soil, lake sediments and drinking water were analyzed for the concentration of endosulfan products. Blood samples of boys and girls were analyzed for endosulfan products, chromosomal anomalies, and hormones related to growth, thyroid and reproductive system. Paediatricians examined the willing subjects for assessing the sexual maturity. The team also used satellite images of the study area to assess the stream flows. This is a complete study of a small sample of the exposed population. They submitted their preliminary report in 2001 and final report in 2003 to the National Human Rights Commission. Sayed Habibulla was the principal investigator. A portion of the data from this report was published in Environmental Health Perspective, a peer-reviewed published by the US National Institute of Environmental Health Sciences.


The NIOH study was based on a small sample, which is less than 2% of the total exposed population. Dr Y Mohankumar, a physician with more than two decades of practice in Padre village had published his shocking finding of 171 patients with severe disabilities and cancer in 126 households. Details are given below:


Mohankumar Database
Households 126
People (estimated) 756
Cancer 51
MR 38
Psy 49
Epilepsy 33
Total cases 171
Percent 22.6
Source : Y Mohankumar



The Findings and Non-findings of NIOH


Human Health

NIOH did find some statistically significant increases in some health problems in the study population. These are:

  1. Delay in sexual maturity like appearance of pubic hair in adolescent boys.
  2. Earlier menarche among girls
  3. Goiter incidence was higher among girls in the study area.

The mandate of NIOH from NHRC was to look into the rare and serious anomalies like mental retardation, cancer and other congenital anomalies, as reported by Dr Y Mohan Kumar, who has been practicing medicine in village Padre for about three decades. He had information on 175 diseases/disorders from 125 households. From the final report of NIOH: “ Our analysis of family data do not support the observations of Dr. Mohan Kumar with respect to high incidence of cancers, asthma, dermatitis and suicides. This should be investigated by studies involving larger populations.” NIOH final report 51

Health Problems in Cattle

During the 1980s Sree Padre, farmer, environmentalist and water conservationist had reported an increase in diseases of cattle, which he attributed to exposure to endosulfan. Reproductive fitness of the cattle was also included in NIOH study. birth deformity in cattle in the study area was 1.3% as against 1.6% in the reference area. Rate of infertility in cattle was 4 times higher in the reference area. Thus they concluded that “some of the reports in the press have shown congenital malformations and other problems in the cattle. Our preliminary inquiry in this matter is showed that no significant differences in health problems were reported by the subjects in the two areas”.

NIOH made the following recommendations to the NHRC:

Extensive epidemiological studies in the areas where endosulfan has been sprayed should be carried out to investigate occurrence of illnesses similar to those reported in Padre village.”

High exposure groups such as workers engaged in formulations, application and manufacturing of endosulfan and areas with high usage of endosulfan should be studied to determine the long term health effects of the compound.”

The populations included in the present study should be followed up for the detection of endocrine related cancers.”

The physiography of Padre village has been a major factor responsible fond continued

exposure of the population.

To sum up, NIOH team did not find any increase in diseases prevalent in PCK villages and are associated with endosulfan in the public mind. And the conditions significantly higher in the exposed community, though important from a scientific and research point of view, are not the major source of worry for the exposed people. NHRC and the governments ignored the main recommendation to undertake a full-length, detailed long term epidemiological study of all exposed persons. There are serious design defects in this study and these might make any extrapolation of the findings to the total exposed communities impossible.

Design Defects of NIOH study

The study has two major design defects – (1) Endosulfan was found in soil samples and blood samples from the reference villages also. (2) Difference in age structure and sex ratio between the study and reference groups and between the samples and the mother villages from which the samples were drawn.

1.The problems of exposure and non-exposure

NIOH was mandated to study the effects of exposure to endosulfan on health. This means that the exposed group should be compared with a comparable unexposed group, which will be known as the control group. NIOH found endosulfan products in soil samples from Meenja also. Concentration of endosulfan in the top 7.5 cm of soil from Meencha was five times higher than in the study area. The pesticide was also found in blood samples from both areas. 34% of the female subjects and 14% of the male subjects from Meencha had endosulfan in their blood. The mean concentration of endosulfan products in their blood was 2.8 nanogram (nanogram = one billionth of a gram) in females and 4.7 nanograms in males. Likewise, endosulfan was not detected in blood samples from 15% of the females and 23% of the males in the study population. There were three exposure groups in NIOH study – (a) no exposure (b) low dose exposure and (c) high dose exposure. The Meenja sample consists of those with no exposure and low dose exposures and the Padre sample consists of subjects with no exposure and high dose exposure. (Details in table 2)

Table 2
Endosulfan in blood – Reference and Study samples of NIOH
Reference Area Study Area
Female Male Both Female Male Both
Total subjects 35 48 83 67 97 164
Endosulfan positive 12 14 26 57 76 133
% Endosulfan positive 34.3 29.2 31.3 85.1 78.4 81.1
NIOH Final report p 18

In the preliminary report submitted to the NHRC, Meencha village was named as the control area and the students were labeled as control subjects. In the final report, the label has been changed as reference area and reference population. From NIOH report: “Our major criteria for the selection of reference population was the similarity (in) ethnic background, climate, food habits, occupations, crops and socio-economic status and absence of aerial spray of endosulfan. We therefore selected Meenja Panchayat area as control. As the endosulfan was also found in this population which was presumed to be not exposed to significant amounts of endosulfan, the term “control” used in first report has been replaced by the term reference group”. (P 46) In the paper published in the Environmental Health Perspective a year later, the compared population is referred to as the control group.

In short, this is not a comparative study of exposed and unexposed groups. This is a study of students of a school which was proximate to sprayed village with the students of a school that was not under the toxic cloud. Their results could have been radically different if the comparison groups were students with and without body burden of endosulfan.

2.Sampling Problem with the study populations

When large number of people is exposed, it may be impossible to study all of them. Restricting the study to a small sample is usual and permitted. Especially so if high tech endpoints like studies of hormones, DNA mutation and concentration of toxins in nanogram levels are to be measured. NIOH study sample consisted of less than 2% of the people chronically exposed to endosulfan continuously for twenty years. In such cases, the sample selected for the studies should be more or less similar in sex and age structure, socio-economic status, cultural traits and life styles.

The age and gender composition of the NIOH sample is given in table 3. The last row gives data of total population and sex ratio in villages Padre and Meencha, the sources of the samples.

The sex ratio (males per 1000 females) in Meencha village from which the reference sample is drawn is 989. Likewise, Padre from which the study population is drawn has a sex ratio of 970. These values are comparable to the sex ratios of rural Kasargod. Sex ratio of the reference and the study populations in the sample is 835 and 782 males per 1000 females respectively. Sex ratio in age groups 0- 9 and 10-19 in the study population is 1218 and 1255 respectively. The normal sex ratio in age group 0-9 is 1040. SR is aberrant in the reference area also with 1080 boys in 0-9 years (male excess) and 842 (male deficit) in age group 10-19. If these were true, both the samples might have experienced a serious reproductive bottleneck or higher death rate in young people during 20 years before the study.

Table 3:  



Reference Study
Age Group Male Female Total S R Male Female Total S R
<10 243 225 468 1080 229 188 417 1218
10-20 340 297 637 842 404 322 726 1255
20-30 82 151 233 678 121 204 325 593
30-40 23 187 210 575 40 202 242 198
40-50 7 70 77 241 29 95 124 305
50-60 12 25 37 800 15 50 65 300
60+ 31 34 65 674 46 70 116 657
Total 738 989 1727 835 884 1131 2015 782
Mother village 1856 1876 3732 989 2821 2688 5509 1049

Source: Table 34. NIOH for data on study and reference populations

District census handbook for village statistics (Last two rows)



Because of the difference between the age structure and the sex ratio between the study and reference samples and population in Kasargod villages, extrapolation of the findings in this study to the total exposed population may not be possible.


The Government of Kerala Committee’s study was headed by Dr Sukumaran and included experts in medicine, cancer epidemiology, environmental sciences and agricultural sciences. While NIOH study was in-depth and high-tech, Sivaraman committees work was very extensive. It covered 160,000 people, half them ‘exposed’ to endosulfan. Suskumaran committee report is mirrored on the website of the Endosulfan Relief and Rehabilitation Council.

This is not a study, only a compilation of data on disability collected by the Health Department. The committee’s findings are given in two tables (without table numbers) on pages 21 and 22 of the report. The first table has raw data on disabilities in 8 villages called endosulfan-sprayed villages. The second table has data on same diseases in 7 villages which were not endosulfan sprayed. Usually such data are converted into rates (per 100 or 1000 or 100,000) and rates in exposed and unexposed populations are compared using an analytical software. The committee did not do this.

This graph shows that in three villages – Enmakaje, Panathady and Kallar there is a serious problem. Risk of all the conditions taken together is five and a half times in Enmakaje, three and a half times in Panathady and three times higher in Kallar. In Cheemeni and Ajanur, there are small differences of 20% and 13% respectively. But these would not be statistically significant. The prevalence of diseases in Karadka, Mooliyar and Periya is lower than in unsprayed area. In Periya, there are only two persons with disabilities out of a total population of 9,388. There is nobody with mental retardation or cancer there. To sum up, there are three villages with disability rates higher than the normal, and three villages with disability rates lower than the normal. One can argue that the excesses in the first three villages were due to endosulfan. The normal question a sensible person will ask is “why there is lower disease burden in other villages.


There are two groups of stake holders on this side of the fence of endosulfan debate. The first group consists of the inhabitants of the polluted territory. Some individuals among them are suffering from debilitating diseases, most of them incurable. Suffering of some families with mental retardation can be considerably reduced by setting up day care centres. According to rough estimate, some 50 to 100 centers need to be set up in the affected areas. As of now, there are only two centres. Some of the endosulfan children with conditions like profound mental retardation require constant care and attention, causing wage loss to the mothers who are usually burdened with the task of taking care of the disabled. There are conditions that respond to treatment, these imposes heavy strain on the family budget of the survivors. Immediate relief and a permanent solution on the financial compensation are the primary need of this group of stakeholders. Since endosulfan can cause mutation, the impacts of exposure during 1980-2000 will be felt several decades and even generations later.

Under the existing legal framework, the is payment can only be decided by a tribunal or a court. Thirty years after the beginning of the aerial exposure experiment and ten years after it was terminated for safety reasons, there is no database which will help the counsels of the victims to argue for the case of compensation. A delay of two years in the appearance of moustache and advancement of menarche by one year are really important issues. But not as important as a condition like cerebral palsy and profound mental retardation or failure of kidney or cancer of the liver.

The second group of stake holders is the environmentalists, who demand a toxin free environment by reverting to more scientific farming, without using hazardous chemicals. NIOH paper published in Environmental Health Perspectives will satisfy this group. This is the first report of a statistically significant increase of some abnormalities detected in human beings subjected to long term chronic exposure of endosulfan.

Most of the victims and their parents are not in a position to read and understand the reports of the expert committees written in technical English. If the claim for compensation has to go through a tribunal, the existing evidences will be blown into bits. The NIOH study was mandated by the NHRC in response to the media reports that projected the observations of Dr Mohankumar. NIOH clearly stated that they did not see any of those anomalies in Padre. Without studying the reports, the National and the State Human Rights Commissions have been making radical demands on the Governments. These may be good copies for the media and music for the environmentalists. These statutory bodies have wasted more than eight years.

VT Padmanabhan





Brief biography

  1. Study of genetic effects among 70,000 people living in coastal villages of Kollam and Alapuzha. Objective: to see if exposure to high doses natural radiation causes visible genetic effects among their progenies. Results – positive. Published in International Journal for Health Services
  2. Study of growth pattern of children born to survivors of Bhopal accident. Exposed parents’ children born several years after the accident suffered significantly. Journal of American Medical Association.
  3. Study of occupational health of workers exposed to ionizing radiation in the Aluva plant of the Indian Rare Earths. High rate of cancer and genetic disorders. Economic and Political Weekly
  4. Study of birth of children born in Plachimada before 5 years and after 5 years of CocaCola Bottling plant. Mean reduction of 200 gm in birth weight. High Power Committee appointed by the Government of Kerala
  5. Study of radioactive burden to river Periyar and the Arabian Sea by the Indian Rare Earth’s thorium milling facility at Eloor, Economic and Political Weekly
  6. Study of occupational health of workers in Gwalior Rayon’s viscose rayon plant at Nagda in Madhyapradesh – Published in EPW and PUCL.
  7. Study of goitre and auto-immune thyroiditis among women in reproductive age groups living in the ‘local area’ of the Madras Atomic Power Plant – under consideration for publication
  8. Study of cancer and genetic effects among the scientists and workers of three nuclear power plants in India – under publication
  9. Review of official genetic studies conducted among the survivors of atom bombs in Hiroshima- Nagasaki – under editorial consideration
  10. Review of death due to cancer and other diseases among the survivors of atom bombs – being submitted.
  11. Study of climate change mitigation potential in organic farming. This ongoing study is looking into soil carbon sequestration in organic and non-organic farms in three Indian states.
  12. Impacts of nuclear weapons tests on global climate – ongoing.

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