Incineration

It is well recognized that Dow’s Midland plant incinerators and tar burners were the major source of the toxic dioxins and furans still being found today at very high levels in Midland Area soils.

There may be a tendency to minimize Dow’s responsibility with the assumption that the company was unaware that the emissions from the incinerators were toxic to downwind employees and city residents.   With the limited analytical capability that was available in the 1930’s to 1950’s, it is certain that Dow did not know that dioxins and furans were present in the dark smoke and black soot that frequently settled on Midland.

However, research into the history of the Midland plant reveals a pattern of continued operation of the tar burners and chemical waste incinerators even though the units were emitting large volumes of dark smoke and black soot.  There is ample written evidence that indicates that Dow recognized that the black smoke and soot were visible signs of incomplete combustion but continued to operate the units rather than curtail production levels.  The most probable cause of incomplete combustion – chemical waste loads that exceeded the design capacity of the incinerators and tar burners.

The reluctance of the company to match incineration capacity with growing chemical waste volumes resulted in the burning of chemical wastes in the on-site powerhouses the 1960's and, possibly, into the 1970's.

It is difficult to understand, with the knowledge that Dow must have developed (even in the 1930’s and 1940’s) about the toxicity of its chemical wastes, that the company wasn’t aware of the potential toxicity of the emissions resulting from the incomplete incineration of hazardous chemical wastes.  Very simple animal vapor exposure tests, well within Dow’s technical capability, would have confirmed the toxic nature of the emissions.  Samples taken of the tar-like residues that collected inside the chimneys of the tar burners and incinerators could have been tested to determine acute toxicity.  There is no published information that this rudimentary testing was ever carried out. 

Each reader should decide which is worse — continued incineration and tar burning operations recognizing that emissions were hazardous or a failure to determine whether the emissions were harmless or toxic.

An overview has been written that traces the historic development of incineration technology at the Midland plant from the first coal-fired tar burner to the state-of-the-art air pollution control equipment that is able to meet Federal and state dioxin emission limits.

The overview contains information on the following topics.

     • Dow incinerators and tar burners
   • TCDD levels in chemical waste tars
     • Incineration of waste tars in on-site powerhouses
    

The link to the overview is Incineration Overview