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Porphyria Educational Services



PORPHYRIA EDUCATIONAL SERVICES Bulletin Vol. 1 No. 28 July 11, 1999
FOCUS: Hexachlorobenzene & Glycol Ethers:
More Unsafe Chemical Toxins for Porphyrics

Hexachlorobenzene Hexachlorobenzene is a white crystalline solid. This compound does not occur naturally. Hexachlorobenzene was widely used as a pesticide until 1965. It was also used to make fireworks, ammunition, and synthetic rubber.

It is formed as a by-product during the manufacture of chemicals use for making solvents, other chlorine-containing compounds, and pesticides. Small amounts of hexachlorobenzene can also be produced during combustion processes such as burning of city wastes. It may also be produced as a by-product in waste streams of chlor-alkali and wood preserving plants.

There are no current commercial uses of the substance.

Hexachlorobenzene tends to remain as a solid in the environment for a long Most of it will be in the form of particles clinging to the bottom and sides of lakes or streams, since it does not dissolve in water very well. The evaporation of this substance into the air is not significant under ordinary conditions GLYCOL ETHERS What are Glycol Ethers?

Glycol ethers are another of the chemical toxins that are harmful to porphyria patients and are a potential trigger of an acute porphyric attack.

Glycol ethers are organic solvents. Many different glycol ethers are used for cleaning. They are often found under the trade names "Cellosolve" and "Carbitol." Glycol ethers are volatile organic compounds (VOCs) and may be regulated in your area. They are also combustible or flammable and must be handled accordingly.

Glycol ethers are used in the semiconductor industry to strip photo-resist. They also remove flux, solder paste, inks, greases, and oils. They are often blended with other solvents for specific cleaning applications.

The terms E-series and P-series are often used to refer to ethylene glycol ethers and propylene glycol ethers, respectively. E-series members generally are more toxic. A semiconductor industry study has linked two E-series glycol ethers to an increase in miscarriages among assembly line workers. The two specific compounds studied were diethylene glycol dimethyl ether and ethylene glycol monoethyl ether acetate. The time weighted average (TWA) for ethylene glycol methyl ether acetate is 5 ppm, but miscarriage increases have been linked to lower exposure levels.

Glycol ethers tend to emulsify well for cleaning and separate easily during recovery. One method for disposal is to burn the solvent in an approved chemical incinerator.