Nearly a decade after clean-up efforts began on a gasoline leak from an old underground fuel tank at the city’s maintenance shop, the Island is still paying about $75,000 a year in clean-up efforts.

“We’ve made progress,” said Glenn Boettcher, maintenance director, “but it’s been slow going.”

The clean-up has included groundwater filtering, chemical injections and air injections. Boettcher said it’s not unusual for a clean-up such as this one, to take 20 years or more and that this was a “a small issue in the context of things.” The city will have spent $410,000 by the end of 2014. Another $570,000 will have been covered by Washington Cities Insurance Authority, the city’s insurer, by the end of 2014.

The three underground fuel tanks were removed from the site at 9555 S.E. 36th St., just behind City Hall, more than 20 years ago when the city paid to dispose of them and a sizeable amount of contaminated soil. Contamination was first detected in 1991, northwest of the maintenance shop, where the Honeywell Industries building sat. A device was installed to remove vapors from the soil, but was never activated when paperwork was lost at City Hall. Over time, gasoline traveled through the groundwater onto the property to the west of City Hall. When a potential buyer took interest in the Honeywell International site, soil and underground water testing was conducted in July of 2004.

Golder Associates had been coordinating the clean-up for the last ten years, but the city recently  contacted another firm, Farallon Consulting, to determine if efforts could be accelerated at all. Boettcher said he expected the city to make “modest adjustments to Golder’s approach.”

“Unfortunately, it’s not unusual for a clean-up like this to take 20 years or more to complete,” he added.

The city may be eligible for some reimbursement if it meets the state’s clean-up requirements.

Farallon Consulting’s recommendations are still in draft form but Boettcher said the most significant suggestion was to conduct additional underground exploration to see if there is still contamination around where the tanks were removed. Remaining contamination might indicate that the pollutants are still spreading onto the adjacent property.