The Directorate General, Factory Advice Service and Labour Institutes, Mumbai, had launched a national survey on Safety, Health and Working Environment in Pesticide manufacturing industries in India as a part of Plan Scheme on Chemical Safety in 9th 5 year plan. The objective of the survey was to assess the hazard potential associated with manufacture of different pesticides and their formulations and to prepare an action plan in order to strengthen the occupational safety, health and work environment in the industry.
The teams of three disciplines (Process Safety, Industrial Hygiene and Industrial medicine) were formed at each of the four labour institutes working under the Directorate General namely, Central Labour Institute Mumbai and Regional Labour Institutes Kanpur, Kolkata and Chennai. On the basis of the preliminary information gathered from the pesticide industries, about 20 sample units were selected for including in the study. While doing so, it was ensured that the selected units represent each type of pesticide chemicals and their formulation industries in the country.
The protocols were prepared for the each discipline i.e. Process Safety, Industrial Hygiene and Industrial Medicine, which were to be followed by all the teams in order to ensure collection of complete data and uniform evaluation in all the regions. These included checklists and questionnaires and standard methodologies for collection of samples, laboratory analysis and medical examinations and related investigations. Attempt was made to complete the tasks within the time frames decided for them and cover all the selected units. Some shortfall did, however, occur, which could not be prevented due to unforeseen circumstances.
The sample industries included mainly two categories of factories i.e. those manufacturing basic pesticide chemicals and those manufacturing formulations out of the basic chemicals. Most of the basic chemical units also had the facilities to manufacture some types of formulations.
Most of the basic chemical units employed batch processes, which have more or less similar processes. The process safety studies in such chemical units revealed similar safety related deficiencies. About 100 recommendations covering various aspects of process safety have been summarised in the report. A few important findings and suggested interventions are again being given here:
- In most of the units the main reactions involved moderately exothermic reactions, which were being managed by manual adjustment of cooling water and feed flow. Keeping in view the highly toxic nature of materials involved. It has been suggested that reactors should be provided with temperature indicators with high temperature alarms and interlocking with reactant feeding flow.
- Most of the units make use of many batch tanks through which the reactant liquids are fed indo the reactors. Non of the factories had maintained these tanks with proper overflow pipes, level monitoring devices, flame arrestors in vents etc. It has been recommended that all the batch tanks should be kept up with best available safe practices.
- Most of the reactions are carried out with constant agitation of the contents. Even though many of the factories had interlocked the feed flow with power failure, yet in none of the factories any thought regarding mechanical failure of the agitator blades has been given. It has been suggested that the amperage of the agitator motors should be monitored and system should have interlocking with any sudden drop in the amperage of the agitator motor.
- Some of the reactions in such units evolved highly toxic gases like hydrogen sulphide, hydrogen cyanide, hydrogen chloride etc. Even though most units had arrangements to collect such gases from the reactors and neutralise suitably. There are, however, possibilities of system failures and release such gases into the working zones. It has been suggested that continuous monitors with alarm should be provided for such gases to warn the employees on such eventualities.
- Highly toxic and reactive solids like sodium cyanide, phosphorous Penta Sulphide, chlorphenols etc. were being charged into the reactors. Some of the units did not have proper arrangements to ensure safety of workers during this operation. It has been suggested that properly enclosed and locally exhausted enclosures should be provided for charging such solids.
- Some reactors and kettles were being operated under negative pressure which had the possibility of vessel implosions in case of uncontrolled vacuum. It has been suggested that such vessels should be provided with the vacuum breakers.
- Many highly flammable substances like ethyl alcohol, benzene, methyl chloride, toluene, ethyl mercaptan etc. were being used in such units without due precautions to prevent fire and explosions and to minimise the losses in case of such explosions. It has been suggested that such operations should be provided with proper earthing and bonding, flame arresting devices, explosion vents, inert atmosphere etc.
- In some factories, many hazardous chemicals were being stored without due attention to their hazardous nature. The suggestions to store the different types of substances safely have been put forth in the report.
- None of the factories was found to have been classified their premises into flammable areas for the purpose of flame proofing the electrical equipment and fittings. It has suggested that the areas should be earmarked flammable zones and displayed adequately.
- Some of the chemicals were likely to evolve toxic substances on involvement in fire. It has been suggested that information in this connection should be made known to all the employees.
- The awareness about the hazardous properties of various substances handled was lacking among the workers in some of the factories. It has been suggested that the MSDS for each chemical should be made available to all the concerned employees in the factories.
- Most of the factories had prepared the on site emergency plans and submitted to the respective enforcement agencies for approval. It has been suggested that the plans should be rehearsed and upgraded periodically on the basis of the shortcomings observed.
The monitoring of work place environments in various factories by the industrial hygiene teams revealed the conditions on the basis of about 70 recommendations have been summarised in the report. The underlying suggestions are being reproduced here:
- The concentrations of pesticides and other harmful air borne contaminants at the working locations and the breathing zone of workers were found in most of the chemical plants manufacturing basic pesticides were found to be within or in the range of permissible limits of exposure or threshold limit values. Yet, suggestions have been made to further improve the conditions.
- The filling of basic pesticides in drums produced the objectionable levels of the pesticide vapours at most of the places. Suggestions to carry out this operation under efficient local exhaust system with the use of proper types of respiratory protection or mechanisation of the operation to avoid any person in proximity has been suggested.
- Manufacture of coated granules by adsorbing the active pesticides in the filler materials was found to generate objectionable levels of toxic pesticide vapours and dusts in the work environment. Suggestions have been made enclosing the processes and locally exhaust the work platforms. Proper decontamination of the air before venting out the exhausted air has also been recommended.
- Most of the factories preparing Dusting Powders (DP) and Wettable Dispersing Powders (WDP) made use of the pulverisers having open bag filters for filtering pneumatic conveyor air. These filters released very high levels of dusts and vapours within the workrooms. This resulted in objectionable levels of dust / vapour in the work environment. It is recommended that use of such pulverisers should be discontinued at least for such toxic substances. The pulverisers with enclosed bag filters with arrangements to remove the contaminated air and let out through high stack are available which should be used.
- The preparation of Emulsifiable Concentrates (EC) did not evolve high levels of pesticide vapours in the workrooms. The operations like filling and packing of containers were occasionally found to generate high pesticide levels in the rooms. Possibility of contamination due emergency exposures on accidental spillage of basic chemicals or prepared EC was, however, identified. Suggestions have been made to carryout filling and packing operations under effective local exhaust and use of proper respiratory and body protection has been suggested. Mechasation of the packing operations has also been suggested.
- Some factories had good system of bathrooms, change rooms and cloak rooms for keeping their street clothes. In some factories clothes and protective devices were being washed and disinfected by the company within the premises. It is suggested that all the factories should be provided with such facilities and be properly maintained.
- Some factories had maintained good safety showers and eye wash fountains and displayed the procedures for their proper use. It is suggested that all the factories should have proper decontamination facilities.
- The level of awareness on safety, health and hygiene was found to be less among most of the factories. Introduction of various awareness schemes has been suggested.
The occupational health study involved the medical examination of about nine hundred workers from different sample factories. The findings of this part of survey revealed the following conclusions:
- The general signs and symptoms of pesticide related illnesses were found to be significantly higher among the exposed workers as compared to the unexposed workers.
- The inhibition of cholinesterase activity in the blood samples of the exposed workers was found to be significantly higher than that of the unexposed workers.
- No significant difference was observed in the lung functions, ECG, haemoglobin and albumin and sugar levels in urine of the exposed workers a compared to the unexposed workers.
- The Occupational Health Centres, ambulance vans and availability of occupational health experts and/or trained first aiders in most of the factories were inadequate. It has been recommended that the facilities should be maintained as per the applicable statutes.