During the Subcommittee Hearings on February 9 and 10, 1977, relative to the proposed Clean Air Act Amendments, a number of questions were posed concerning the use of MMT, a manganese octane-improver additive, in motor gasoline. Comments were made on this subject by representatives of General Motors, Ford Motor Company, Texaco and others. At the hearings, much of the testimony was directed at informing the Subcommittee of a number of potential problems that might stem from the continued use of MMT . Senator Domenici indicated that this matter was of grave concern and requested additional information. In response to this request, Exxon has additional information and comments which we wish to bring to the attention of the subcommittee. They are summarized below and amplified in the attachments. First, we wish to comment on some of the statements made at last week's hearings. Contrary to impressions left by statements made in testimony, the We believe that the data presented describing potential plugging Second, we wish to enter additional information into the record which demonstrates the compatibility of MMT with catalyst systems and which documents the importance of MMT in meeting consumer gasoline requirements. A DIVISION OF EXXON CORPORATION Senator Edmund S. Muskie -2 February 15, 1977 Before Exxon began using MMT in gasoline, we evaluated all The EPA hosted a meeting on January 20, 1977 attended by auto The use of MMT as an octane improver in unleaded gasoline is a vital part of gasoline manufacturers' aggregate ability to supply anticipated consumer gasoline needs at appropriate octane quality levels. If the use of MMT is restricted, the near-term results are likely to be a combination of the following: (1) Gasoline supplies will be reduced, possibly to levels causing (2) Gasoline quality levels will be reduced resulting in poorer (3) Lead levels in leaded gasoline will rise, counter to the EPA plans to phase down lead in gasoline. Additional plant capacity to replace the octane that would be lost if MMT is eliminated would normally take at least three years to build and bring onstream. Elimination of MMT would result in an added nationwide capital cost estimated at $2 billion. This alternative would also increase national consumption of energy and crude imports, because obtaining needed octane through refinery processing, rather than MMT, is much more energy-intensive. Ultimately both of these increased costs would be borne by gasoline consumers. Before a judgment can be made on whether MMT use should be limited, 84-239 - 77-40 Senator Edmund S. Muskie -3 February 15, 1977 In summary, we do not think it is appropriate to reduce or eliminate the use of MMT at this time. We believe that EPA should continue to function as the organization to screen data generated on the effect of MMT on emission systems. If the presence of MMT in the fuel precludes meeting emission levels set by Congress, and system modifications cannot be developed by the auto makers to handle MMT, then EPA has the authority, under Section 211 of the Clean Air Act, to take appropriate action. However, this should only be done if a thorough evaluation of all available data and all consequences of that action demonstrate that it is justified. Sincerely, CRS/hf1 CC Senator Pete V. Domenici CDsitter ATTACHMENT I ASSESSMENT OF MMT PERFORMANCE IN CATALYST SYSTEMS The data obtained by the car manufacturers showing adverse effects of MMT are very limited and in our estimation do not warrant a conclusion that the use of MMT should be restricted. At a meeting sponsored by EPA on January 20, General Motors reported catalyst plugging with 1977 California Novas which have a design modification incorporating close-coupled, monolith oxidation catalyst systems. Partial plugging of a conventional pelleted catalyst mounted in the toe-board position on another type vehicle was also reported. Both incidents were attributed to the use of manganese, but because the data were obtained under severe test conditions which have not been correlated with consumer use, we question whether non-typical temperatures and temperature cycles may not be the prime reason for these problems. One G.M. test showed higher engine-out hydrocarbon when using MMT. However, the amount of test work reported is limited and the question is unanswered whether higher platinum loadings of the catalyst or somewhat different operating temperatures might not counter the apparent effect of MMT. G.M. also reported incidents of plug fouling, but there was no evidence of misfiring. All of these tests were run under very severe conditions which have not been correlated with consumer use. None of the other automobile manufacturers furnished hard data on the effects of MMT. At this same meeting the preponderance of data presented by petroleum companies and additive manufacturers showed no detrimental effects from the use of MMT. Exxon Research and Engineering Company reported on their work on MMT which included -2 a Ford V-8 run in an engine test cell, four 1975 California vehicles run on a mileage accumulation dynamometer, and two 1975 compacts in short trip service. No adverse effects were found in any of these tests, and MMT did not increase engine-out hydrocarbon. At the end of the January 20 meeting, the EPA representative stated that after reviewing all available data, the EPA concluded that 0.125 gram manganese per gallon in the form of MMT should be used in all certification fuels for 1979 model year cars. This indicates that the preponderance of data does not show that MMT is incompatible with existing emission control systems and that it is the agency's intent to certify 1979 vehicles under conditions which are expected to exist in the field at that time. Before a judgment can be made on whether MMT use should be limited, further work must be completed by both the petroleum and automotive industries. To this end there are a number of activities already under way. An API subcommittee is at work, with EPA and auto companies assisting, attempting to reconcile differences and inconsistencies between data developed by car manufacturers and others. One of the concerns being addressed is whether the test cycles used in evaluating the effects of MMT are related to actual consumer use. EPA is monitoring all field complaints that could possibly stem from the use of MMT. To the best of our knowledge none has been found to date. Research programs are underway at various facilities. For example, Exxon Research is running additional tests on engines and vehicles, including two California |