If any step in the synthesis of heme is blocked, an intermediate chemical accumulates in the cell, resulting in oxygen depletion.

Those intermediate chemicals, known as porphyrins or porphyrin precursors, are the substances of which heme is composed.

It sells products such as gasoline, diesel, jet fuel, ethanol, polymers, intermediate chemicals, base oils and asphalt.

Newspaper reports say the police found byproducts of nerve gas and intermediate chemicals made in the manufacture of nerve gas.

The company makes and sells intermediate and specialty chemicals.

Hydrogen cyanide is used in the chemical industry for the production of intermediate chemicals like acrylonitrile, methyl methacrylate, and adiponitrile.

"In simple terms, they're the intermediate chemicals that are produced before making the final product ," the undersheriff explained.

However, final products from one plant may be intermediate chemicals used as feedstock in another plant for further processing.

Thus many intermediate chemicals used in dye manufacture have been identified as toxic and their use restricted.

The chloride has several important applications as an intermediate chemical for production of neodymium metal and neodymium-based lasers and optical fibers.