Document QkJOVZbVkyp4k7eGY2BdeypG8

io *tOC*T*0* L. G. Scharpf, Jr. - NIA February 18, 1976 PENTACHLOROPHENOL M. C, Throdahl - DID cc W. B. Bennet J. S. Metcalf D. P. Roman P. A. Tierney - N1A - B2NC - nia - nia Per our conversation coday, atcached is Information relative to out position on pentachlorophenol and our current research plana. As I indicated to you, ve are still very much In the pent business and are trying to stay In It because of the dependency of Santophen 1 on the utilization of chlorophenol fractions by the penta process. What ve have said Is that If EFA required us to distill penta to reduce the dioxin contents 've votild likely discontinue production of penta. Our preliminary estimate of the capital required for distillation Is $8M and the additional cost 20-25c per pound. We don't think the wood treating business could support these in creased costs. On the basis of existing information, ve think Chat there is no demonstrated need*to control the dioxin content of penta which will be used in professional wood treating establishments. We do feel there Is a further need to characterize the impurities In penta, and determine If they represent any risk to the environment or plant worker. Work is under way In this area. Finally, as insurance to our Santophen 1 business, we are examining alternative process routes to reduction of chlorophenol "fractions" to the lowest practical level. An oxychlorination process based on cupric chloride can theoretically provide an 80-852 reduction in "fractions" production. We are currently examining the parameters of this process and will write a R & D Process Outline which could be used for an economic evaluation. At this stage our probability of success is 502. Please call if I can be of further assistance. LGS/dc Attachments L&i L. G. Scharpf, ad dn, r i i- a ed ties e 3. not and ind n en aese ers se") . a* <*** C IO WW5 v I JS Monsanto D*ri *47 4*4 TO * : W. B. Bennet/D. P. Romaa - NIA February 18, 1976 PENTACHLOROPHENOL ENVIRONMENTAL STATUS * L. G. Scharpf, Jr. - NLA cc P. G. Hamner - B3SC E. E. Hendrikse - B2NA J. S. Metcalf - B2NC J. P. Mieure - T2F P. A. Tierney - NIA s.. H. Vogel - 1740 P. L. Wright - A2SC 1. Background Pentachlorophenol enjoys widespread use as a wood preservative. Commercial grades have been found to contain up to 2500 ppm chlorinated dlbenzo-p-dioxins. The predominant dioxin is octachlorodlbenzo-p-dioxln, one of the least toxic members. Evaluating pentachlorophenol toxicity in animals revealed that some untoward effects (chloracne, chick edema disease, and histopathologic alterations) were caused by chlorinated dlbenzo-p-dloxln content. Purified pentachlorophenol did not produce these effects. The basic molecular 'structure of dibenzodioxin is given in Figure 1, along with a concise summary of the toxicology of the family of chlori nated dlbenzodloxlns. The most toxic member of the family, 2,3,7,8tetrachlorodibenzodioxin (TCDD), was discovered as an impurity,in the herbicide 2,4,5-T and its presence in the environment has focussed attention on the entire spectrum of dioxins. The probable mode of formation of OCDD (octachloro-dioxin) under penta manufacturing conditions is shown in Figure 2. Less highly chlorinated dioxins could be formed from lower chlorinated phenols. Other impurities known or assumed to be present In commercial penta are shown in Figure 3. 2. Environmental Considerations TCDD (and probably other dioxins) was found to be immobile in soils, not readily taken up by plants, subject to phocodecomposition, persistent and only slowly degraded in soils. Despite these properties efforts to find TCDD in soils heavily created with herbicides found far less TCDD than expected. Host analyses to establish its presence in wildlife have been negative. A widely publicized finding of less than one ppb in Vietnamese fish is-suspect. Pentachlorophenol was first implicated in 1957 when millions of broilers died with symptoms of excessive pericardial fluid ("chick edema disease") <* . * 7J "lOw SUBJECT TO PROTECTIVE ORDER- -&TTTTZ" o o a ri7V6 -- pci* C1903S L. G. S c h a rp f, J r . February 18, 1976 Page 2 Certain feed fats were implicated and traced to by-product tallow (fleshing greases) recovered from hides treated with tri- and pentachlorophenol preservatives. Concern has been expressed that OCDD (major dioxin in penta) might be readily reduced to the more toxic hexachlorodlbenzodioxin in the environ ment but this has not been demonstrated. Meager reports on migration of dioxins into soil from penta-created wood poats give negative findings. Human Safety HCDD (hexachloro-dioxin), which is present in commercial penta, has been shown in animal tests to cause chloracne. Reports of incidence of chloracne in humans engaged in manufacture and use of penta in wood treatment are conflicting. The EFA la conducting a survey of woodtreating operations. Monsanto is in the process of examining Its own medical records and industrial hygiene practices -in Che manufacturing department. 4. Analysis of Monsanto Penta Analytical techniques for the minor constituents of penta have changed continually since 1970. The present best technique consists of isolating non-phenolic components by alumina column chromatography and analysis by electron-capture GC with confirmation by mass spectroscopy. Limited data on our production penta Indicates no TCDD and no pentadloxins detectable in our product. Hexa-, hepta- and octa-dioxins are about 15, 200 and 500 ppm. Interferences in mass spectrometry procedure have to date not permitted an estimation of* the level of chlorinated dibenzofurans. No information on "pre-dioxins" (or their possible toxic properties) is available except they are'known to be present. 5. Dioxin Removal Dioxins can be removed from penta (to appreciably, less than 30 ppm total) by recrystallization or by distillation. Cost of a distillation instal lation would be high (esc. $8M) and added production cost would be 20-25c per pound. Biological Tests Penta has anLDsp of 270 mg/kg in rats. At levels below the lethal dose penta gives positive response in chick edema testing and positive acne response in the rabbit ear test. A number of experimentally produced penta samples (lab and plant) have shown lower response, but only distilled penta showed no response. There is, however, a distinct discrepancy in the chick edema tests in that the response found for commercial penta was greater than could be accounted for by the dioxins present. IAL ~f,:UECT TO PROTECTIVE ORDER -g o t r r r r ^ L. C. S c h a rp f, J r . February 18, 1976 Page 3 Politic! Climate Environmental groups are pressing loudly for banning 2,4,S-T and other dioxin-containing herbicides (e.g. a full-page article replete with cartoon in the Washington Post, 1-25-76, partly funded by the Fund for Investigative Journalism). Hence, the EPA is under political pressure despite the negative findings outlined above. Penta is tarred by the same brush since it contains dioxins, though the highly toxic TCDD is generally recognized to be absent. EPA is concerned about penta-dloxln, but we have not found it in peat* by our best techniques. EPA has requested Its Science Advisory Board to review the health hazards charged to penta, the economic Impact of cancelling pent* on a use basis, and health implications of use of alternative wood preservatives. Dow Chemical has commercialized a distilled pcntachlorophenol with 30 ppm (max.) total dioxins and has urged EPA to restrict production to this type of material. Other producers feel that the type of dioxins in penta pOse no problem if use la restricted to wood treating for outdoor use. Research Plans Research will concentrate on the areas of Industrial hygiene and the analysis and biological testing of minor constituents as follows: a. The nature and extent of health problems, if any. In the chlorophenol, penta and Santophen 1 units will be found and preventive measures recommended If needed; b. Penta will be separated into phenolic and non-phenollc components for individual bio-testing in an attempt to clarify anomalies in our present analytlcal/toxlcological correlations; c. The technique of liquid chromatographic separations will be used to better identify minor components (particularly "pre-dioxins" and chlorinated dlbenzofurans) and, to the extent possible, provide samples for toxicological testing; d. Dioxins analyses will be obtained for all products from the chlorophenols complex where data now is admittedly sketchy; e. Some effort will be expended on Investigation of migration of dioxins from treated wood into the surrounding soil; f. Monsanto will participate in government committees on dioxins research and possible round-robin analytical testing. CONFIDENTIAL s i e r r o w m c n OODB. ^-i 0 33 j 7 ^ Q-9&} ?43 <PCV~ C19040 L. G. S c h a rp f, J r . February 18t 1976 Page 4 The economic of Santophen 1 manufacture depend to a marked extent on manufacture of penta from by-products of the Santophen process. Research is under way on a process to lessen this by-product formation appreciably. W. B. Bennet D. P. Roman /dc .L i'.* !!* i U3JECT TO FE/TZC71VE ORDER. 03 3 l C19041