Tahoe two-stroke ban based on flawed data | SierraSun.com

Tahoe two-stroke ban based on flawed data

It is time the people of the Donner Lake region learned the facts regarding the recent ban of two-cycle engines by the Tahoe Regional Planning Agency (TRPA).

Board members of TRPA and a small group of extremists have obscured the truth of this issue and have allowed their pre-conceived notions to color their decision. It is ludicrous to use the ban on Lake Tahoe as a blueprint for decisions regarding two-cycle engine use on Donner Lake

The ban by the TRPA started out as a nuisance and safety issue regarding personal watercraft. The irresponsible use of these boats by a small percentage of people prompted TRPA to attempt to ban them. The TRPA quickly learned that the sounds produced by personal watercraft were well within the guidelines of Nevada and California.

Further, the safety issue was found to be better addressed by enforcement and education. The focus then shifted to environmental issues. When it was discovered that singling out personal watercraft would be viewed as discriminatory by the courts, the focus shifted again to include all two-cycle engines in the proposed ban. Negotiations between TRPA and various user groups resulted in the present makeup of the ban. In essence, TRPA has achieved its goal of banning all personal watercraft and outboard engines above 10 horsepower produced over the past 40 years.

The problem with all this is that the premise upon which it is based is flawed. A review of the scientific research over the past 25 years has shown that two-cycle marine engines do not pollute the waters in which they operate. The exhaust products of two-cycle engines consist of undifferentiated hydrocarbons only loosely related to gasoline and lubricating oils. It is true that the hydrocarbon emissions of two-cycle engines exceed those of four-cycle engines (the type used in most pleasure boats and automobiles). However, it is also true that four-cycle engines produce 9 times the amount of oxides of nitrogen than two-cycle engines.

What follows are the facts of two-cycle marine engines according to studies conducted by the US EPA, European environmental research groups, and the ongoing studies at Lake Tahoe:

1. Two-cycle motor emissions “do not significantly affect aquatic ecosystems”.

2. The exhaust hydrocarbons “remain in the water column for a relatively short time, less than a day, under conditions normally encountered in natural water systems before they are removed by natural physical (evaporation), chemical (absorption), and/or biological (bioxidation) processes.

3. “No statistically significant buildup of saturated hydrocarbons was observed in the test ponds’ sediment after 3 years of engine operation”.

4. “The average engine will contribute 2.5 percent of its’ fuel to the water. After 30 days, less than 20 percent of this remains in the water and each 11 days, this would be reduced by half.

5. Two-cycle marine engines contribute only .3 percent of the hydrocarbon loading to the air in the Lake Tahoe Basin.

6. The decline in clarity of the water in Lake Tahoe comes from the growth of algae due to nitrogen loading of the lake. Since, as stated above, the oxides of nitrogen, and its possible conversion to nitrates, are more likely to come from four-cycle engines, it is ludicrous to demonize two-cycle engines for this. The bulk of the nitrate loading of the lake comes from development and the 1,875,000 vehicle miles traveled in the Lake Tahoe basin every day.

7. Roger Eggenberger, director of utilities for IVGID testified that in 10 years of testing the water of Lake Tahoe, no hydrocarbons from boating activities have been detected.

8. Jim Scribner, who has worked for the Placer County Environmental Health Department at Tahoe City, testified that no organic compounds that might be associated with gasoline could be detected at any of 27 randomly selected sites around Lake Tahoe.

9. The vaporized exhaust product of two-cycle marine engines is markedly dissimilar from the fuel fed to the engine and cannot be categorized as “gasoline”.


Methyl Tertiary Butyl Ether is a valid concern for Donner Lake residents. It is abundantly clear that MTBE will be removed from not only the gasoline in the Lake Tahoe basin, but from all gasoline due to the deleterious affects on public water supplies and the ineffectiveness in improving air quality It is ironic, however, that the people of Lake Tahoe are so upset at the California Air Resources Board (CARB) stubborn refusal to admit the mistake in this issue yet allow TRPA to be as stubborn in the two-cycle engine issue.

Despite all of the evidence, TRPA was unable to divorce itself from its’ prejudice against personal watercraft. It directed TRPA staff to draft an environmental document to support a ban on two-cycle engines. The document thus produced is replete wfth inaccuracies, assumptions, and outright misinformation. It is upon this faulty document that TRPA has based the ban. At first blush, personal watercraft do appear to pose an environmental threat. It is only after a careful evaluation, which anyone can do, that the truth shines through the misconceptions.

The propaganda campaign waged by some members of the Board of Governors of TRPA to justify their prejudices and biases regarding this issue shows an underlying disregard for the facts. This campaign was well financed, well orchestrated, and well conducted by charismatic people. It achieved its’ objective by replacing reality with perception. The TRPA is an unelected group, accountable to no one but themselves and operates without oversight . It behooves all of the people in the Donner Lake area to put facts before perceptions and to study this issue with a scientific eye so as not to allow incorrect political perceptions to prevail.

I strongly urge the residents of the Donner Lake area to consider the above when attempting to condemn personal watercraft or limit the use of these boats. It is crystal clear that with education and enforcement, most problems associated with personal watercraft can be eliminated

Russell Anders is a doctor and a resident of Sacramento.

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