Urban pesticide exposure disables workers in Catalunya

More than 30 serious pesticide exposure incidents have taken place due to urban pest control operations in workplace buildings in Catalunya, Spain. At least 50 people have been so seriously affected they have been classified as unable to work. The Barcelona Centre for Health and Safety Conditions at Work has played a leading role in identifying pesticide exposure as the cause of their initially mysterious illnesses. Francisca López Crespí, José Brosa Luengo, and Jordi Obiols Quinto now report their findings. 

One accident affected the nursery in a social services building. Swabs taken from various parts of the nursery contained residues of chlorpyrifos, permethrin, tetramethrin, propoxur and piperonyl butoxide. All storeys of the building were affected and remained closed for seven months. The percentages of samples with residues are shown below.
Analytical results of samples from one accident
Air (3 samples) Furniture and toy surfaces (5 samples) Floor and furniture dust (9 samples) Insulation materials and filters (5 samples)
Chlorpyrifos  100%  100%  100%  100%
Piperonyl butoxide  100%  55%  60%
Permethrin  40%  44%  60%
Tetramethrin  60%  22%  40%
Propoxur  11%  60%

Traditionally, the major risks from pesticides are associated with making, formulating and applying these products in agriculture. However, their increasing use to disinfect buildings presents a risk for many workers in offices and other workplaces. Exposure tends to go unnoticed because it is not directly linked to the nature of the work being carried out. Because of this, it is almost never identified or evaluated and is not adequately controlled.
    In Catalunya (Catalonia), the Barcelona Centre for Health and Safety Conditions at Work (CSCSTB), with the support of the Barcelona National Centre for Conditions at Work (CNCT of the National Institute of Safety and Hygiene at Work, INSHT), collected information on adverse health effects on workers who, although they did not work with pesticides, were nonetheless exposed due to pest control operations in their workplace. Between April 1994 and October 2003, 38 incidents were registered, mostly in the province of Barcelona, involving a total of 678 workers. Results from a questionnaire used to determine relative impacts indicated that 301 (44.3%) were affected to varying degrees. Of these, 135 (44.9 %) were considered slightly affected, 103 (34.2%) considered moderately affected, and 63 (20.9%) considered seriously affected. This last group were advised to seek follow-up in the Medical Reference Unit so their pathologies could be assessed in Barcelona. Fifty out of these 63 were confirmed to be seriously affected. More than 100 additional cases are currently under study. These cases reached CSCSTB as a result of reports made to Workplace Authorities, from unions, or from legal claims made by the affected workers. Occasionally CSCSTB found out due to queries made by the companies themselves, and in one case due to an insurance company dealing with accidents at work. 
    Currently workers with pronounced effects are sent to CSCSTB by the Occupational Health Units (Health Department) from cases referred by family doctors. Each reported accident is investigated jointly by the Industrial Hygiene section and the Inspection of Work section. Where symptoms have arisen, and the Health section has been informed, the epidemiological services carry out a parallel investigation of the symptoms.
    A wide variety of workplaces are involved in this type of accident, including teaching centres, hotels, old peoples’ homes, office buildings, banks, laboratories and social health services. At times activities have come to a standstill and in some cases this has been permanent. Companies specialising in decontamination have had to be employed and sometimes large quantities of office material have been destroyed, office furniture and carpeting removed, some interior decoration (e.g. false ceilings) removed, painted surfaces scraped, and absorbent material (curtains, bedclothes, mattresses) changed before the contaminated area can be reoccupied.
    Those affected are not usually diagnosed correctly at first, due to the variety of symptoms and to ignorance of workplace exposures. The persistence of medical problems over a number of years is common in those who experience marked symptoms in the weeks after the pesticide treatment with longer-term effects largely neurological and/or behavioural. To date, more than 50 people have been classified as unable to work to varying degrees, with an additional 30 workers awaiting reclassification by courts. 

Estimation of the risk 
In 1999, Dr. Baselga Monte calculated that the number of cases recorded in Catalunya corresponded to 31% of those actually occurring – that is, 69% of cases went undetected. (The percentage of cases undetected in other regions of Spain could be as much as 100%.) According to these calculations annual exposure could affect 4.33% of the working population in Catalunya, and the annual incidence rate could be 19.61 accidents per 10,000 pesticide applications, involving 19.71 people per 10,000 exposed.
Given the persistence of the health effects, some of which are disabling – between 5% and 10% of cases – the risk requires aggressive action to prevent further incidents.

Exposure to pesticides as a source of risk
In the majority of accidents studied, and in all those resulting in permanent health effects, the presence of at least one organophosphate pesticide has been identified. The two most frequently identified are diazinon and chlorpyrifos. Compounds belonging to the pyrethrin and pyrethroid families have also been found relatively frequently, but not alone. 
    A total of 21 different pesticide active ingredients have been identified in the 38 cases studied. These have been either recorded as used and/or detected analytically in the accidents studied. Between two and five different active materials are normally identified in each case including:

Additional risk factors
In some cases, the pesticides applied were not authorised for use indoors, or the products recorded as used were different from those which were detected analytically. In other cases, the records had been duplicated, such that there were two records corresponding to the same application, each stating that different products had been used. Some applications were carried out by companies not authorised to make such applications. Incorrect information on the chemical composition of some preparations has also been detected. Some of the recorded products included formulations not intended for use indoors, such as creosote.
    In almost all cases the information supplied to workers in the workplaces being treated was inadequate, and this was often aggravated by incorrect cleaning after pesticide application. Often the areas where pesticide poisonings have taken place have certain characteristics, such as airtight areas, absorbent floors and hangings, inadequate ventilation after the application, or no air exchange of any kind. The absence of ‘good practice’ when pesticides are applied implies, indirectly, the simultaneous occurrence of one or more risk factors in every accident, such as making the same application more than once, incorrect dosing, failure to observe safety intervals before re-entry after applications, lack of signposting to indicate treated and affected areas, applications made whilst the occupants were still present and, occasionally, products not authorised for use indoors. 

Table 1. Prevalence of the 12 leading symptoms
Symptoms  cases  % of sample
headaches  213  70.7%
chronic fatigue  177  58.8%
respiratory difficulties  146  48.5%
sense of smell affected  140  46.5%
sense of taste affected  106  35.2%
menstrual changes  86  32.2%
nausea/vomiting  90  29.9%
loss of muscular strength  84  27.9%
muscle contraction  72  23.9%
diarrhoea  59  19.6%
changes in oral/labial sensitivity  48  15.9%
changes to tongue sensitivity  33  10.9%
301 cases affected, of which 34 were men, and 267 women

Health impacts 
Amongst those studied, women clearly predominate – there were 501 (73.8%) women and 178 (26.2%) men, with an average age of 35 years (plus or minus 15). In general, those affected had a large number of symptoms involving different organs within the body, in particular the nervous system. They experienced alternating periods of greater and lesser symptom intensity, with symptoms becoming chronic and persistent with time, without the person recovering completely. The large variation in symptoms between people makes diagnosis exceedingly difficult if exposure to neurotoxic insecticides in the workplace cannot be proved. In 56% of the cases where the person was suspected of being more affected, there were more than 15 clear symptoms persisting for months.
    The study and classification of the 201 different primary symptoms observed in the cases treated has made it possible to group them into 58 symptoms, from which 12 leading symptoms have been identified (Table 1). When these are present, pesticide poisoning is suspected.

Chronic effects present after ten years
Follow-up of the first groups to be accidentally exposed has provided early evidence of the following combined effects in workers who, prior to the accident, had not requested medical attention owing to these disorders:

Interestingly, all four disorders (except menstrual changes which only affect women) were noticed together in each affected worker. These were accompanied by a large number of additional potential symptoms, especially painful sensations, respiratory, digestive and urinary symptoms, and alterations in sensitivity. 
    Objective studies have been made via different diagnostic tests of neurological changes, predominantly to the central nervous system. Using evoked potentials (visual, acoustic, and somesthetic), electroencephalograms (EEGs), cerebral SPECT (body section radiography), cerebral and pituitary gland NMRs, visual digital campimetry (visual field defects), and neuropsychological assessment, a range of changes were detected. The study protocol has been progressively widened as more patients have been studied.
    In the most serious cases, the workers have become unable to work. The most serious difficulties re-integrating people into their jobs have resulted from Multiple Chemical Sensitivity, Chronic Fatigue Syndrome, and, for those with technical qualifications, the reduction in their intellectual abilities resulting from the neurophysiological changes. These changes were largely in the frontal lobe, but in the most serious cases also affected the temporal and parietal lobes of the brain.

Considerations when using pesticides inside buildings
The proof in this study of the irreversibility of the effects suffered by those who were affected by pesticides, and the permanence of these effects in the most serious of the cases, forms a solid basis for an alert focusing on the repeated, and frequently unjustified, use of pesticides in indoor work locations and, by logical extension, in any interior used by humans. On this basis, the following guidelines should be emphasized:

1. The utmost effort should be made to avoid certain pesticide treatments due to the possibility of their causing damage to people using the area. Special attention should be paid to treatments in residential centres or centres where the users are especially vulnerable (children, old people, the ill) and to applications in work centres which are open all the time.
2. The use of pesticides indoors should be strictly limited to personnel who have received adequate technical preparation and who have received legally accredited training. Applications should be carried out according to procedure, using authorised and registered formulations. Complete and truthful disclosure of the risks, the precautions to be taken, and the correct protocol with respect to third parties, must be observed.
3. Given that health problems must occur during the weeks after pesticide treatments, statements of these should remain with the companies in a record book. If possible, these should be numbered to prevent subsequent alterations. Where adverse effects do occur, these should also be recorded. First of all, medical attention should be guaranteed to those affected, but care must be taken to ensure that the accidental exposure of all those who have shown the same type of problems is also recorded in the relevant part of the work accident report (whether with or without casualties).
4. Information must be guaranteed to reach all those who work in the areas treated, especially if they do not do so generally or all the time. Workers who do cleaning merit special attention, as do guards and caretakers, or companies who are sub-contracted and who could be working at times when regular workers are not present.
5. Routine insect removal treatments in companies are completely contraindicated. There is no technical justification for this. In any case, products with the least toxicity possible should be chosen.
6. Other pest control methods should be put forward, which are not exclusively chemical in nature. If the use of pesticides is necessary, it should be limited to the treatment zone, and applications systems which generate minimal dispersion and liberation of the product in indoor environments should be chosen.

Francisca López Crespí and José Brosa Luengo, Barcelona Centre for Health and Safety Conditions at Work, Department of Work and Industry, of the Catalonian Government, francisca.lopez@gencat.net, josep.brosa@gencat.net. Jordi Obiols Quinto, National Centre for Conditions at Work, Barcelona, National Institute of Safety and Hygiene at Work, Ministry of Work and Social Affairs, jorgeO@mtas.es

[This article first appeared in Pesticides News No. 68, June 2005, pages 3-5]