preparation sectional graphic

Oil Drip Survey

Black Rock City 2002 Oil Drip Survey Results and Management Recommendations

Prepared by Roger Farschon, April 2003 Bureau of Land Management Black Rock Desert - High Rock Canyon Emigrant Trails National Conservation Area


The Burning Man event has been conducted every year but one since 1990 on BLM administered public lands on the playa of the Black Rock Desert. As the event has grown in attendance from an initial few hundred to almost 30,000 in 2002, controversy over use of the public lands for the event has grown. A controversial issue remains the amount of environmental impact thousands of people may cause to the Black Rock City site. For most of the year, the location remains a naturally barren expanse of playa surface; part of the much larger playa of the Black Rock Desert. During the event the 15,000-acre event site becomes the fourth largest city in Nevada: with streets, a sanitation system and thousands of parked vehicles.

During the permit processing for the 2000 event, BLM received an appeal from Desert Rescue and John Bogard. One of the points (item 61) raised in that appeal stated:

“As the Gier Report demonstrates, and as the EA admits, large quantities of pollutants ranging from motor oil to detergent to human waste are deposited in the Playa Surface during the Burning Man event. The pollutants remain on or near the surface until the next raining season when they are inducted into the hydrological cycle of the lake and enter the seasonal lake that forms each winter” (Black Rock Rescue et al, 2000)

Attached to the appeal was a report from Joel E. Gier (2000) that included a discussion of the impact of oil dripping from vehicles onto the surface of the playa. Specifically, the report identified risks to ground water from an estimated 100 gallons of oil dripping onto the playa surface from one tenth of an ounce of oil per day dripping from each of an estimated 16,000 vehicles. Gier also postulated other vehicle related hydrocarbons including transmission fluid, brake fluid and hydraulic fluids as well as anti-freeze were dripping onto the playa surface in quantities sufficient to affect water quality. However, at the time neither Gier nor the BLM had specific data to quantify how much oil might actually be deposited or to document the fate of the oil. This study attempts to provide some insight into these questions.


Random point locations were generated in the ArcView 3.2T Geographic Information System software within the polygon that conformed to the maximum extent of the street grid for Black Rock City 2002. These points (n=102) were plotted over the grid map of the City. The points represented the most likely areas where motor vehicles would be parked for more than a day.

The fifth day of the event was chosen for sampling to assure that a large number of vehicles would be present, that many vehicles would have been parked in these locations for multiple days and to increase the chances that the owners of theses vehicle would be available. The following day, the day the “man” was burned, there would have been more vehicles in the city and increased parking time, but the large number of activities associated with the burn would have reduced the number of vehicle owners expected to be “home” . An afternoon was chosen for sampling as the most likely period when vehicle owners could be easily contacted. The bright sun reflecting off the light surface of the playa also made dark oil spots stand out against the naturally light beige playa surface.

Each observer was assigned a block of points within the City as shown on a plot map. The observer found the location that corresponded to each point location using the map references on the plot. Because of the configuration of the street grid, the observers felt that the accuracy of locating the sampling point on the ground was good. When the point was located the observer then selected the vehicle that was closest to the selected sample point.

For each sampled vehicle the following information was collected:

Number of Days the vehicle had been parked at this location: This information was obtained by asking the owner or other knowledgeable party. Information was recorded to the nearest full day.

Type of Vehicle: Each vehicle was assigned to one of four categories:

Commercial Vehicle:   Bus, Tractor trailer, other large truck
Motor Home:   Self-propelled, self-contained motor homes
Car/Van:   Passenger Car or Van
Truck/SUV:   Pickups, SUVs

Condition of Vehicle: Each vehicle was assigned to one of three categories:

New:   Vehicle appears to be less than 5 years old
Intermediate:   Vehicle appears to be more than 5 years old and in good condition
Beater:   Vehicle could be of any age, but signs of damage, abuse or non-typical modifications (e.g. art cars)

Drips: Does the vehicle drip oil, from what location and what is the diameter of the drip spot on the ground? (Where a pan or other protective device captured a drip and no drip was reaching the playa surface, no drip was recorded except as a comment.)

Other information: Any additional comments from the observers.


Field inspection of 102 vehicles revealed a total of 19 oil spots associated with 16 vehicles. Thirteen of the 19 spots were one inch diameter or less. Drip information is summarized in Table 1.

Drips and vehicle condition were inversely related as shown in Figure 1. New vehicles represented almost 60 percent of the vehicles surveyed but were associated with less than 20 percent of the drips. At the other end, “beaters” were associated with almost 45 percent of the drips but represented less than 13 percent of the vehicles surveyed. These differences were significant at P<0.001 using a Log-Likelihood Ratio test with 3 degrees of freedom (Zar, 1984).

Drips and vehicle type were found in proportions similar to the sampled vehicle types as shown in Figure 2. Differences were not statistically significant. One observation of notes was that commercial vehicles were four times more likely to have drips than expected. However, two of the four commercial vehicles with drips were labeled as Art Cars in the comments.

An analysis was conducted to determine the relationship between drip presence and size and the number of days a vehicle was parked in the same place. There was no statistically significant correlation between the days a vehicle was parked and drip presence or drip size. This would indicate that if a vehicle drips, the detection of the drip could occur soon after the vehicle was parked.

Other observations of note:

  • Three of four vehicles identified as Art Cars were observed to be dripping.
  • Two of the observers saw vehicles with drip pans to catch oil drip.
  • Most of the participants interviewed expressed support for the effort to inventory and take measures to decrease oil drips from vehicles.


The presence of drips associated with 16 percent of the surveyed vehicles means that about 1 in 6 vehicles were dripping oil. The average size of the oil spots was about 1.5 inches in diameter indicates that most dripping vehicles deposited small amounts of oil on the playa surface. Peak visitation for the 2002 Burning Man event was almost 30,000 individuals and using a ratio of 4 visitors per vehicle (BLM, 2001 & 2002), that equates to about 1,200 dripping vehicles. No vehicles were observed dripping brake fluid, hydraulic fluid or anti-freeze. The sample was too small to provide an indication about these drip types other than to show that they are rare.

The median number of days a surveyed vehicle had been parked at the same location was three. The median number days each vehicle would be parked during the entire event is estimated to be five. This assumes that most vehicles remain through Saturday, the day the man is burned, and leave sometime on Sunday. Using an average of one drip per hour, about three tenths of an ounce per day would drip from 1,200 vehicles. This would result in about 14.5 gallons of vehicle related hydrocarbons Percent deposited on the playa surface during the event. This is substantially less than the 100 gallons estimated by Gier in his report.

Nicholas M. Johnson (2000) in a response to the 2000 Appeal estimated the fate of Gier's estimated100 gallons of oil and concluded hydrocarbon concentrations could be as high as 50 parts per billion (ppb). Johnson's estimate conservatively assumed a volatilization of no more than 50 percent of the hydrocarbons and no offsite mixing in the seasonal lake that intermittently forms over the event site with other parts of the playa lake. Adjusting the analysis of Johnson to reflect the estimate of 14.5 gallons per year, non-volatile hydrocarbons within a seasonal lake at the Black Rock City site concentrations would be 7.3 ppb. Johnson's conservative estimate was based upon simplifying assumptions about the depth of the water in the seasonal lake and no forces that would spread hydrocarbons away from the location of the City. These assumptions would almost never be valid with actual concentrations higher or lower. Johnson felt that actual concentrations “would probably be much lower” than his calculations.

Oil dripping onto the playa would be adsorbed onto the clay and silt particles and remain on or near the surface of the playa. The water table associated with the playa moves up and down on a seasonal basis related to the amount of run-off from the surrounding uplands and precipitation amounts received directly on the playa. When the water table reaches the surface, up to half the oil, which has a specific gravity less than water, would be carried to the surface, be dispersed as a thin film and either directly volatilize into the atmosphere or be photo-degraded into smaller molecules and then volatilized (Johnson, 2000; Taffet, 2000).

The site has been used for the Burning Man event for three consecutive years. Cumulatively the concentration of hydrocarbons in surface waters could be higher than the calculated estimate of 7.3 ppb. However, the probability that the cumulative level is additive are considered low due to the factors discussed above. Hydrocarbons would be removed from the site by dispersing winds that spreads the “lake” over a much larger area of the playa that the original site of Black Rock City. Wind movement of surface particles with attached films of hydrocarbons would disperse hydrocarbons across wide areas (Taffet, 2000). Hydrocarbons exposed to the intense sunlight would also breakdown leading to increased levels of volatilization. Hydrocarbons would be subject to biological, physical and chemical breakdown and would be eliminated from the system over time.

The net affect of oil leaking onto the playa surface on biological systems is largely unknown. Peter Brussard and Donald Sada (2000) identified a number of risk factors to phyllopod crustaceans that are likely to reside in the playa silts. However they did not present specific information about the presence, habitat requirements or environmental limitations of phyllopods that are expected to reside there. Johnson's (2000) analysis concludes that due to the dispersal and breakdown of hydrocarbons associated with seasonal changes in water tables, winds and lake dispersal there would be insignificant risks to ecological systems. This study does not answer whether or not oil dripping from vehicles presents a risk to the biological systems associated with the playa. It does indicate that the potential impacts identified by Gier (2000) would be unlikely to have the magnitude than Gier suggested.

Management Implications

The goal of BLM and the public is that the event leaves no long-term impact on the playa and surrounding environment. The survey points to potential actions that are likely to decrease the amount of oil that drips onto the playa.

The survey revealed that Art Cars and vehicles that appear to be in poor condition, e.g. “beaters” , are much more likely to drip oil than other types of vehicles or vehicles in other condition classes. Art Cars are required to receive permits from the Burning Man Department of “Mutant” Vehicles. Part of the permitting process could be notification that all Art Cars will be inspected for oil drips and that drip pans or other absorbent materials are required for all dripping vehicles. Specifically the licensing and inspection process should be added to the rules contained in: and include a section on inspection of vehicles for oil drips and remedies required for dripping vehicles.

Dripping “Beaters” or other dripping vehicles can be targeted in advance by adding oil drip information and sensitivity to the following Burning Man websites:

This would target potential dripping vehicles before they arrive on the playa and lead to increased knowledge of the issue and some preventive maintenance of vehicles before the journey to the playa. The event greeters should be trained to identify potential dripping vehicles, equipped to provide disposable pans or oil absorbent and provide instructions on their use.

The stipulations in the BLM permit should be modified to incorporate oil drip information. A requirement to research and develop a disposable drip pan or other absorbent materials that could be distributed to known dripping vehicles should be considered as a new stipulation.

Specifically, I recommend addition of the following stipulation to the resource protection section of the stipulations in future permits:

Black Rock City LLC will make educational materials available to participants prior to the event that explain the need to inspect vehicles and repair or modify those with drips of oil or other fluids. Black Rock City LLC will also train staff involved with greeting participants to identify vehicles likely to have an increased risk of oil or fluid drips, to inspect vehicles and take appropriate actions with to vehicles exhibiting drips.

Follow Up Actions

This study addressed only one part of the issue related to oil on the playa. Additional work is needed to confirm that oil drips are dispersed by the fluctuating water table and other means described in this report and are ultimately volatilized, thus posing no risk to on or off site water tables. A start in determining this could be accomplished through the creation and monitoring of oil spots of known volume.

Studies that focus on the biological systems associated with the playa are needed including inventories of what species are present and how recreational events potentially affect their life cycles and habitats.

Following establishment of the recommended stipulation, surveys should be repeated to determine if the recommended actions are effective in reducing oil drips on the playa.


Black Rock Rescue et al. 2000. “Notice of Appeal of Record of Decision, Finding of No Significant Impact and Stipulations Pertaining to Special Recreation Permit Application and Permit No. BLM-NV-020-00-3.”

Brussard, Peter and Donald Sada. 2003. Letter to Keith Sugar dated September 3, 2000 on sensitive biological issues in the Black Rock Desert.

Bureau of Land Management, 2001. File memo from Brigitte Baslee on random car counts conducted as part of the BLM event monitoring.

Bureau of Land Management, 2002. File memo from Brigitte Baslee on random car counts conducted as part of the BLM event monitoring.

Gier, Joel E. 2000. Comments in response to BLM “Burning Man 2000 Final Environmental Assessment NV-020-0023” . Attachment to Black Rock Rescue et al's Appeal.

Johnson, Nicolas M. 2000. “Technical Response to Significant Hazardous-Substance and Water-Supply Alleged in Black Rock Rescue et al's August and September 2000 Briefs Appealing Permit No. BLM-NV-020-00-3. Unpublished Report.

Laws, Edward A., 1993. Aquatic Pollution: An Introductory Text. 2 nd Edition. John Wiley & Sons, New York.

National Research Council, 1985. Oil in the Sea-Inputs, Fates and Effects. National Research Council, National Academic Press, Washington D.C.

Taffet, Michael J., 2000. “Technical Response to Notice of Appeal and Further Statement of Reasons in Support of Appeal of Black Rock Rescue and John Bogard. Re: NEPA for Burning Man Event near Gerlach, Nevada-Permit No. BLM-NV-020-03-3. Unpublished Report.

Zar, Jerrold H. 1984. Biostatistical Analysis, 2 nd Edition. Prentice-Hall, Englewood Cliffs, NJ.

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