Chronic dermal exposure is a common outcome of allowing women, children and untrained men to handle hazardous chemicals. Gloves and protective clothing are generally effective, though they should be decontaminated or thrown away after use. No one should touch products that are not branded, adequately labeled and cleared for use by a reliable regulatory authority. Risks are exponentially higher for those who smoke or chew tobacco. Risks are higher in hot sunshine. Hazardous chemicals used in Agriculture should be kept secure and inventories recorded. Women, children, the old and the sick should be moved out of range during Public Health operations such as fogging. People should not move barefoot or touch surfaces that have been exposed to or treated with chemicals, until the waiting period specified by the manufacturer is over. Chronic dermal exposure is generally easy to avoid if there is a complete record of all chemicals with which one comes in contact, and protective measures built around the vulnerable points. Certain traditional practices such as rubbing tobacco with lime between palm and forefinger or thumb, are serious routes to chronic dermal toxicity. Impressionable children are especially vulnerable to accepting such habits without appreciation for its hazards and effect on longevity.

Chronic oral toxicity generally takes place if people drink water and eat food that is not regularly monitored for chemical residues. Groundwater near land where chemicals are produced or used is likely to carry percolation residues. Unbranded fruits and vegetables may contain pesticide residues. Washing and cooking generally breaks down most chemicals but one cannot be sure without a reliable log of the pre-harvest interval. The chances of chronic oral toxicity can be significantly reduced by insisting that vegetable and fruit vendors enforce pre-harvest intervals on their suppliers. Industrial water users should be pressured not to discharge water that exceeds biological and chemical oxygen demands and to contain spills and untreated water in holds that are proof against percolation in to soil. Radiation levels in processed food should be declared on labels, even if zero, so that consumers and their doctors can tote up the curies of cumulative exposure. All pesticides are subject to pre-harvest intervals and acceptable daily intake that make some assumptions about daily diet. These assumptions should be known to volunteers, and toxicologists and dieticians enjoined to adjust national limits for ethnic variations in daily food consumption. These limits are often set for able-bodied adults, especially if the safety factor on no-effect levels is low. This is another reason to discount acceptable residue levels, especially in countries where companies wield great influence on regulators.

Chronic inhalation toxicity is likely in chemical processes without controls on air emission. Visible smoke and fumes with odors are not reliable indicators as noxious emissions may be subtle and beyond the limit of human senses. Air quality measurement belongs to the realm of experts and it is best to try and live in the jurisdiction of honest and capable regulators. The incidence of chest ailments and lung cancer in people who do not smoke, may be used as a rough indicator of chronic inhalation toxicity, though findings could be too late for victims in advanced stages of diseases such as cancer. Pesticides used in mats, coils and evaporators, to keep mosquitoes away at night can be very dangerous for children who sleep with doors and windows closed. Dermal toxicity through treated bed nets is a worthy trade-off in areas with dense and numerous stagnant pools.

All forms of chronic toxicity are insidious and can only be monitored by specialists with expensive equipment. Women of child bearing age and children at risk of chronic toxicity should be monitored once a year for development of cancer. Couples should know before conception that women exposed to chemicals may bear teratogenic offspring. Exposed men may have depressed sperm counts, though this is simpler to detect in time. The chances of chronic exposure and severity can be dented through programs to reduce chemical use or to find safer alternatives. Agriculturists, doctors and industrial customers for chemical products are the three most common groups who can drastically reduce the degree of chronic exposure. Transparency in the working of regulators and their direct public accountability greatly improves living conditions and safety measures of poor people and all those with low literacy of the world of poisons.

Acute toxicity occurs at accident sites, during handling of concentrate material or by intention. Each chemical has a Material Safety Data Sheet that should detail how to deal with acute cases. Labels will also have information on first-aid measures and antidotes. The general first-aid rules could be stated as follows:

- Use activated charcoal and try and make the victim vomit is he or she is conscious.
- Wash off dermal exposure with a strong shower of plain water and remove contaminated clothing.
- Evacuate people from the area affected by noxious gas. Use a wet towel or cloth to cover nostril and mouths. Use respirators and masks as far as possible.
- Lay victims in a cool and shaded place.
- Keep stocks of antidote at hand, but let only qualified doctors administer them.
- Quarantine spills and leaks from human and animal contact and prevent run off in to soil and water bodies.
- Keep product labels and material safety data sheets available for doctors and emergency workers to read and use to treat victims.

Companies that manufacture hazardous chemicals are often the best repositories of information on emergency response measures. The reputable ones should have elaborate systems in place within their own manufacturing premises. Dialogue with them and with their industry associations can improve community response capability in significant manner. Long-term rehabilitation of victims and their families can be most expensive and out of reach for poor communities without health insurance. Manufacturers and their associations are important sources of funds to deal with consequences of exposure to their products.

Hospitals, doctors and transporters need special training and aids, to deal quickly and effectively with disasters that arise as a result of large scale exposure to hazardous and toxic chemicals. Community volunteers can act as facilitators to get chemical manufacturers and care givers together, to improve safety conditions related to chemical accidents and related emergencies. Regular communication with poison centers and specialists in occupational hazards also aids general awareness about how to handle chemicals without undue exposure. Toxicologists who study the effects of chemicals on dogs and other animals are important repositories of safety information because of the nature of their profession.

The various routes to chemical poisoning and their complicated nature is an inevitable issue with which modern society must contend. As always, children, the poor and the weak, bear the brunt of the costs and risks. Heightened awareness, collaboration with industry, established disaster recovery systems and transparent accountability of regulators are the 4 pillars on which effective amelioration of the epidemiology of toxicity can be tracked, measured and improved for a safer future.

Written by: Dr S Banerji