404 BULLETIN OF THE BUREAU OF FISHERIES 



benzene hydrocarbons have a paralyzing action on the motor nerves and a more 

 noteworthy action on the brain and cord, causing lethargy and somnolence. Bro- 

 mobenzene and chlorobenzene act in the same way as benzene itself." (May, 1921, 

 p. 19.) As the physiological action or effect of a chemical depends largely upon its 

 ionization, and this again depends chiefly on its solubility, it is conceivable that para- 

 dichlorobenzol is much more toxic than chlorobenzene. It is also known that an 

 increase in the halogen radical enhances the toxicity of chlorobenzene. As we shall 

 see later, Mr. Harrison found that the effluent of the Dow chemical plants actuaUy 

 killed perch immersed in it. There can be no doubt, then, that the dichlorobenzol 

 solutions may act upon the fish either directly by Idlling them outright or by acting 

 as a depressant, or indirectly by destroying the plankton food of herring or by decreas- 

 ing its reproductive activity. I obtained the significant details of the history of this 

 pollution from the various principals involved. For this history I am indebted 

 mostly to Herbert H. Dow, of the Dow Chemical Co. ; W. P. Kavanaugh, of the Mich- 

 igan Fisherman's Association; Louis P. Harrison, Bay City chemist; and to Dr. Her- 

 bert W. Emerson, of the University of Michigan. 



The principal products manufactured by the old Midland Chemical Co., the 

 predecessor of the Dow Chemical Co., were bromine and salt derived from the brine 

 of salt mills. This company did not extract the calcium and magnesium chlorides 

 from the brine but dumped them, with the bittern water, into the Saginaw River. 

 This bittern water derived from the Saginaw salt blocks and dumped into the river 

 contained on an average 50 per cent more salt (NaCl) than calcium chloride and mag- 

 nesium chloride combined. The Midland Chemical Co. "took only about a tenth of 1 per 

 cent^of^the material out of the brine — the balance of it went into the river. " (Dow.) 

 As time went on one product after another was extracted from the brine, imtil at the 

 present time salt is produced only as a by-product for the purpose of recovering other 

 constituents in the brine. 



Upon the outbreak of the war in Europe (fall of 1914) the Dow Chemical Co. 

 began tofsave ^'irtually all their by-products. During the war it manufactured a 

 number of chemicals not made theretofore. Thus, it began the manufacture of 

 chlorbenzol in the spring of 1915. The useless by-products were run into the river. 

 In the fall of 1916 an explosion in the chlorbenzol plant suddenly released into the 

 river a large amount of paradichlorobenzol, a useless by-product at that time. It 

 was also in the fall of tliis year that the water and fish of the Saginaw Bay and the 

 Saginaw River acquired their obnoxious taste and that Doctor Emerson and Mr. 

 Harrison commenced their investigations. 



After the source of the poUution had been discovered the mvestigators found 

 that large amounts of clilorbenzol or its derivatives were being dumped daily into 

 the river by the chemical plant. The explosion was obviously, then, not the only 

 cause of the trouble. It appears that the by-products of chlorbenzol had always 

 been dumped into the river since the beginniog of its manufacture in 1915, and that 

 the sudden release of an enormous quantity of the by-product at one time tainted 

 the fish and water to such an extent as to focus public attention upon this poUution 

 and bring it to a crisis. The investigation culminated in the issuance of an injunc- 

 tion agaiast the chemical company, secured through the State's attorney general in 

 April, 1917. Shortly thereafter the chemical company constructed an artificial pond 



