James:
Organophosphates are so hazardous that the EPA says something that they have never said about any other pesticide.  They admit that there IS no safe way to handle this class of chemicals.

Then he said:
"There are no registered uses of coumaphos on agricultural crops or in/around residences."

Comment:

These are two different things. Coumaphos is not the only OP around.

>17 organophosphate insecticides, as well as additional carbamates, are registered by the EPA for "residential" use, which includes use in and around homes and schools and on playgrounds, lawns, and gardens. (Dursban, the most heavily used insecticide in the country, is an organophosphate.)

see: http://www.nrdc.org/health/pesticides/forgano.asp

As far as Coumaphos, it is used on a variety of animals

>Coumaphos is directly applied to animals or to swine bedding. Liquid formulations can be applied by high and low pressure hand wands, dip vats and back oilers/rubbers. Dust formulations can be applied by mechanical dusters, shaker cans and dust bags.
>
>Use Rates: Use rates range depending on animals treated and formulation type; the maximum label application rates range from 0.005 to 0.025 lb. a.i. per gallon for sprays or dips, 0.076 lb a.i. per gallon of oil for back rubbers, 0.000625 to 0.013 lb a.i. per animal for dust application, and 0.042 lb. a.i. per 1000 square feet of swine bedding treatment.

see: http://www.epa.gov/pesticides/op/coumaphos/overview.htm

End note:
Yes, I am concerned about cholinesterase. I would recommend regular monitoring to anyone who handles coumaphos. Also, have you cholesterol checked !  ; )

pb