A lot of insecticides are inhibitors of the nervous system. These insecticides are also clearly a risk for other organisms like humans. Even more than the acute effects for humans, the effects for children are a problem. Effects exerted at development, at the stage of the foetus or the young child, could be irreversible. If brain development is affected, children could at a later life phase experience effects like problems with their memory, motility or behaviour (see for a review P Grandjean, PJ Landrigan, Developmental neurotoxicity of industrial chemicals, The Lancet, Vol 368 December 16, 2006).

In the US already in 1996 the FQP (Food Quality Protection Act) was changed to account for these effects. Chemical industry placing Organophosphates and Carbamates on the market had to perform tests to find out if an extra safety factor was needed. In Europe this provision is now included in the new pesticide Regulation 1107/2009 (Annex II, 3.6.1):

3.6.1. Where relevant, an ADI, AOEL and ARfD shall be established. When establishing such values an appropriate safety margin of at least 100 shall be ensured taking into account the type and severity of effects and the vulnerability of specific groups of the population. When the critical effect is judged of particular significance, such as developmental neurotoxic or immunotoxic effects, an increased margin of safety shall be considered, and applied if necessary.

Art. 3.6.1 also includes immunotoxic effects. How this provision will be applied is not clear yet. Probably extra data requirements have to be set and extra tests run.

For pesticides a review of developmental neurotoxicity is published (Marina Bjørling-Poulsen, Helle Raun Andersen and Philippe Grandjean, Potential developmental neurotoxicity of pesticides used in Europe, Environmental Health 2008, 7:50, 2008) arguing not enough tests are performed for this effect, and given the uncertainty propose to regulators to use the precautionary principle to protect brain development.

Because most of the effects in later life will be missed in standard pesticide testing, also Theo Colborn stresses the urgence of the problem. She askes for a new regulatory approach including more realistic doses of exposures in tests, functional neurologic and behavioral end points to get a high priority, and to meticulously inventorise the impacts of transgenerational exposure on all organ systems through two generations (Theo Colborn, A Case for Revisiting the Safety of Pesticides: A Closer Look at Neurodevelopment, Environmental Health Perspectives, 114 (1), 2006).