So many of us want things to be simple and “okay.” The response of Angelo Lynn to Chris Fastie’s letter regarding the spraying of malathion to kill adult mosquitoes falls into this category. Were Mr. Lynn to have conducted a little research on the dangers and warnings regarding uses of malathion, he would have learned that it is considered to have the following toxicity levels: high toxicity in the carcinogen and cholinesterase inhibitor categories, moderate in the acute toxicity category, suspected to be an endocrine (hormone system) disruptor, and potentially a ground water contaminant.
Aquatic ecotoxicity effects are noted for amphibians, aquatic plants, crustaceans, fish, fungi, insects, marine benthic organisms, mollusks, zoo- and phytoplankton, and other groups. The chemical is highly toxic to honeybees. This summary information is from pesticideinfo.org, which is published by Pesticide Action Network and includes fully cited information from governmental, international and state agencies, including U.S. EPA and World Health Organization, as well as peer-reviewed literature. 
A quick google search on toxicity of malathion to mammals revealed that as early as 1975 researchers documented psychophysiological effects of malathion on rats.
Does malathion kill adult mosquitoes and purportedly protect humans from mosquito-borne diseases? Yes. Does malathion kill or otherwise disrupt individuals and populations of many organisms, including humans? Yes. Is the spraying of malathion as a mosquito adulticide a simple situation? No.
Would that Mr. Lynn had done a little research and himself written a more balanced response to Mr. Fastie. I know that both of these fine people are very thoughtful and care deeply about their communities and planetary health. Perhaps, when they see a letter that appears one-sided, editors of award-winning newspapers ought to take it upon themselves to present a more-rounded view that captures the complexity of situations we grapple with as individuals and communities.
We live in a culture in which we are accustomed to very casually dispersing all sorts of toxic chemicals into air, water, soils, our homes and our own bodies. Let us not pretend that we do this based on any reasonable look at the effects of these chemicals on human and more-than-human life. When do convenience and personal comfort overrule our desires for lessening toxicity to biota (including Homo sapiens) and ecosystems? Toxic chemicals have long-term, short-term, individual and population level effects; they also disrupt evolution, a very long-term process that has brought Earth’s beauty and diversity to what we know, and grieve the disappearance of today.
Marc Lapin, PhD
Associate Laboratory Professor
and College Lands Ecologist
Middlebury College
Cornwall resident