For Release: Friday, February 22, 2008

DEC Releases MTBE Study of Long Island Gas Stations

Results Show Continuing Impacts of Banned Chemical on Groundwater

Four years after the gasoline additive methyl tertiary butyl ether (MTBE) was banned from New York, the impacts of the chemical continue to pose environmental and public health threats to Long Island's aquifer, according to a new study released today by the state Department of Environmental Conservation (DEC).

The study of 52 retail gasoline stations in Nassau and Suffolk counties concentrated on two known MTBE issues: spills and groundwater contamination. Testing uncovered 32 petroleum spills that had not been previously reported. The spills impacted soils and/or groundwater, with one spill (Ronkonkoma) threatening a public drinking water supply. DEC's actions at the site prevented the drinking water from being effected.

DEC Commissioner Pete Grannis said: "This study confirms that MTBE and other petroleum constituents remain a persistent threat to New York residents' safe drinking water. DEC is committed to continuing to work with state and federal agencies, gas station owners and suppliers, and local governments to closely monitor and quickly address the risks posed by this chemical on our communities."

New York was among the first states in the country to ban MTBE as a gasoline additive and as of 2004, it is no longer legally allowed as a component of gasoline sold in the state. Although banned, the study confirmed that MTBE contamination from known and unknown spills continues to pose risks to the Long Island aquifer system, the sole source of drinking water for over 2.7 million residents of Nassau and Suffolk counties.

DOH Commissioner, Richard F. Daines, MD said: "While the DEC continues to address this threat at its source, the State Health Department, as well as the Nassau and Suffolk County Health Departments, continue to monitor public drinking water supplies to determine that they meet all State and federal drinking water standards and guidelines. Groundwater supplies on Long Island and through out the State are routinely monitored for MTBE and a variety of other organic and inorganic chemicals. We have complete confidence in the quality of our public water supplies."

New York began requiring that public water supplies monitor for MTBE in 1999. The Long Island counties began requiring MTBE monitoring in the mid-1990s. DEC and DOH included MTBE in its investigations and monitoring of leaking gasoline tanks since the late 1980s.

MTBE is a manufactured chemical compound that had been used in New York and other states since 1979 as an oxygenate additive to gasoline to help reduce air pollution. Despite the perceived air quality benefits, DEC grew concerned about impacts to groundwater from spills of gasoline containing MTBE and, in 1998, determined there was a need to further assess the impacts and extent of MTBE contamination.

Prior to the study announced today, DEC had conducted a survey of gasoline spills reported between July 1978 and September 1998 and identified 5,262 spills throughout the state with the potential for MTBE contamination. Of those spills, 1,706 - or 32 percent -- were confirmed to have MTBE impacts on groundwater quality, with the greatest percentage of spill sites with MTBE contamination (24 percent) found on Long Island. This reflects the number of gas stations in a highly populated area, the local geology, and the use of oxygenates and reformulated gasoline to meet federal Clean Air Act requirements to improve Long Island air quality.

Based on these earlier results, DEC launched this new study of MTBE contamination in groundwater on Long Island using a grant from the U.S. Environmental Protection Agency to examine 52 gasoline retail stations that did not have known histories of MTBE blended gasoline spills and were located within an aquifer recharge area. The study was conducted between December 2002 and December 2006. As a result of the inspection and groundwater sampling efforts overseen or conducted by DEC at the 52 sites, 32 petroleum spills were discovered that previously had not been reported. These new spills have undergone or are currently undergoing investigation/remediation.

MTBE concentrations in shallow groundwater at the gasoline stations ranged from "nondetect" to 240,000 micrograms/liter (µg/L). Twenty of the sites had no MTBE detections. Eleven sites had detections of MTBE in shallow groundwater that were below the drinking water standard and groundwater guidance level of 10 µg/L. There were 21 sites with MTBE detections that exceeded the drinking and groundwater standard/guidance and that DEC is requiring action to address; eight of those sites exceeded 5,000 µg/L of MTBE and DEC oversaw immediate remedial action.

Number of Sites with MTBE Detections
Number and Location of Sites	Sites where MTBE was detected below 10 µg/L	Sites where MTBE was detected above 10 µg/L	Sites where MTBE was detected above 5,000 µg/L
Nassau County (17)	47 %	53 %	24 %
Suffolk County (35)	66 %	34 %	11 %
Suffolk & Nassau (52)	60 %	40 %	15 %

The study confirmed that each of the 32 newly discovered spills represent potential sources of MTBE contamination that could impact drinking water supplies or other environmentally sensitive areas. Because of the chemical's ability to migrate with groundwater flow beyond an individual site's boundaries, the potential for MTBE contamination is more widespread than at specific locations such as gas stations. With approximately 1,100 gasoline stations on Long Island alone, the findings of this study are potentially a small representation of the overall impact MTBE is having on the region, as well as other communities throughout New York.

DEC's study recommends:

further groundwater sampling at active gasoline retail stations near public supply wells continue, as it has been proven effective in detecting MTBE and other petroleum constituents around gas stations. DEC has already received another EPA grant and is pursuing the investigation of potential MTBE impacts at an additional 30 gas stations; and
continued support for the Department of Health's ongoing program for routine monitoring of all public supply wells for MTBE and other petroleum constituents to evaluate the State's drinking water supplies. DEC will continue to work closely with the state and county Departments of Health to investigate and address spills as they are reported.

Copies of the report may be obtained at www.dec.ny.gov/chemical/42161.html or by sending an e-mail request to derweb@gw.dec.state.ny.us.