Chlorpropham's LD50 (the dose necessary to cause death 50% of the time) in rats is roughly 2 parts in 1000 -- which for a 100-lb human would be about 3 ounces (of solid chlorpropham).
- How does this compare with other more familiar substances?
- At the levels of exposure present in treated unpeeled potatoes, what measurable health effects are expected?
- How quickly and completely is chlorpropham metabolized by the human body?
It may be that it really is "safe", for any meaningful definition of "safe" (e.g. no more likely to kill you than driving 2-3 hours per day), but if this claim is being made, it is apparently being made in the absence of information which would demonstrate its veracity.
- Wikipedia: stub article
- PAN Pesticides Database
- What's on my Food: Foods With Chlorpropham Residue
- 2001-01-11 Residue Levels of Chlorpropham in Individual Tubers and Composite Samples of Postharvest-Treated Potatoes, J. Agric. Food Chem., 2001, 49 (2), pp 710–714: "The concentrations in individual tubers ranged from 1.8 to 7.6 mg/kg 10 days postapplication (mean 3.8 mg/kg, RSD 39%), from 0.7 to 4.0 mg/kg 28 days postapplication (mean 2.9 mg/kg, RSD 28%), and from 0.8 to 3.8 mg/kg 65 days postapplication (mean 2.2 mg/kg, RSD 48%). ... Peeling removed 91-98% of the total residue; washing reduced residues by 33-47%. Detectable residues were found in boiled potatoes and the boiling water, and in french fries and the frying oil."