Maleic hydrazide is a plant growth regulator used to suppress growth and to induce dormancy in some crops. It is mostly used to reduce sprouting in stored crops, such as potatoes, onions, shallots and garlic.
Chlorate is an effective herbicide due to the oxidative destruction of the plant tissue with release of oxygen. Chlorate was banned in herbicides in 2010 and since it's use is not permitted the maximum residue level (MRL) of 0.01 mg/kg applies. Perchlorate is a similar contaminate sometimes occurring naturally, most abundantly in deposits of Sodium Nitrate in northern Chile.