The Human Toxicity Potential, a calculated index that reflects the potential harm of a unit of chemical released into the environment , is based on both the inherent toxicity of a compound and its potential dose. These by-products, mainly arsenic, sodium dichromate, and hydrogen fluoride, are caused, for the most part, by electricity production from fossil sources. These chemicals are potentially dangerous to humans through inhalation, ingestion, and even skin contact. Cancer potency, for example, is an issue here. HTP is measured in 1,4-dichlorobenzene equivalents (1, 4-C6H4Cl2 eq).