The containers may be coated with harmful chemicals such as chromate , phosphorous , and lead - based paints and its wooden floors may be treated with toxic insecticides , and some cost and effort are involved in modifying containers to make them habitable .
The containers may be coated with harmful chemicals such as chromate , phosphorous , and lead - based paints and its wooden floors may be treated with toxic insecticides . 
 Considerable cost and effort may be involved in modifying containers to make them habitable .