The most common type of contamination encountered at residential properties in New England is a subsurface release or surface spill of No. 2 fuel oil (home heating oil) which may constitute a reportable release condition requiring response actions.  Other types of contamination encountered may include elevated levels of polynuclear aromatic hydrocarbons (PAHs) or heavy metals (such as lead) in surficial soils.  The presence of elevated levels of PAHs or metals may not necessarily constitute a reportable release condition, but a home owner may wish to take corrective action in association with a vegetable garden or exposure to children.  Subsurface releases of Oil or Hazardous Material (OHM) may also have occurred from the historical on-site use of a subsurface sanitary disposal system or dry well.

If you suspect that your oil tank is leaking or your property is otherwise contaminated, please feel free to contact Lingenfelter Environmental Consulting, LLC (LINEC) with any questions you may have regarding your individual environmental consulting needs or for more information on how LINEC may be able to assist you.  Sometimes fast action may protect what is likely to be your largest investment (your home) and/or the environment. Thank you for considering LINEC to provide environmental consulting services.

HOME HEATING OIL

A heating oil leak from an underground storage tank (UST), an aboveground storage tank (AST), or a spill during the filling of an oil tank, is one of the most costly problems a homeowner may face.  A leaking oil tank can lower a property’s value.  Banks and other lending institutions often require that heating oil storage tanks be removed or tested for leaks prior to real estate transfer or refinancing as part of the disclosure policy.  Evidence of a reportable heating oil release or other significant contamination problem may prevent a property sale or refinancing.

Historically, homeowner’s insurance policies typically provided no coverage for a heating oil release or other contamination problem encountered unless there was a demonstrated third party impact.  However, the Massachusetts Senate enacted legislation in December 2008 which required insurance companies to offer coverage for heating oil releases and homeowners to upgrade their existing oil supply line.  As a result of this legislation, many insurance companies may provide residential policy holders with partial coverage for the costs associated with assessing whether or not a third party impact has occurred or may occur at some time in the future (without having purchased the optional coverage).

Home heating oil must be stored in a tank.  Many older and high end homes have a single walled steel UST of between 275 and 1,000 gallons capacity located outside, but adjacent to the residence.  Single walled steel USTs continue to be installed, but most new oil tank installations utilize other materials or combinations of materials.  Newly installed piping associated with USTs are often double walled and made of fiberglass or plastic materials.  The most common home heating oil storage tank in current residential use is the single walled steel 275 or 330-gallon AST located either in a basement or outside immediately adjacent to the residence.  Oil tanks are typically filled and vented through steel pipes.  Heating oil within a storage tank is typically supplied to the oil burner through copper tubing.

Single walled steel USTs historically installed at residential properties did not typically include cathodic protection systems, chemically resistant coatings, dielectric isolation, or sacrificial anodes to protect the tanks or subsurface bare steel piping from corroding.  The most common method by which a single walled steel UST or AST fails is from condensate forming inside the top of the tank (above the oil).  The condensed water then drips down into the oil and eventually settles to the bottom of the tank where it forms a layer of water beneath the oil.  The water corrodes the bare steel inside the bottom of the tank or possibly the bottom of bear steel piping associated with the tank.  Corrosion can begin as pitting on the metal surface.  As pitting due to corrosion becomes deeper, holes may develop.  Even a small hole or a porous soft spot (“weeping” through the steel at the bottom of the tank or piping) caused by corrosion, may result in the release of hundreds of gallons of heating oil to the environment in a relatively short time span.  At some point a tank fill-up may increase the hydrostatic pressure at the bottom of the tank sufficiently to transform a pit into a hole, and create a leak.  Most home owners do not realize that a typical home heating oil AST is only coated on the outside.  An AST may look great on the outside right up to the time that a leak develops.

Historically, the copper tubing supplying heating oil from an AST to the oil burner was often run through the concrete floor.  Copper tubing within or directly adjacent to a concrete floor is subject to corrosion by the cement in the concrete and/or sulfates in the soil beneath the floor.  If a pinhole develops in the supply line, usually under the floor surface, the leak may go undetected for years and result in the release of hundreds of gallons of heating oil.  One of the objectives of the recent Heating Oil Safety Bill was to help prevent spills by requiring relatively inexpensive upgrades to the existing heating oil supply lines associated with an AST.

Additionally, spills often occur at the fill pipe when the delivery truck’s hose is disconnected or an “overfill” occurs.  Spills and overfills primarily result from bad filling practices (human error).  Although these spills are usually small, repeated small spills may result in a big environmental problem.

LINEC provides comprehensive residential services to deal with leaking oil tanks including but not limited to the following:

• Initial site assessment;
• AST or UST removal;
• Contaminated soil excavation, transportation and recycling/disposal;
• Site characterization (soil, groundwater and indoor air);
• Corrective action; and
• Site closure.

PAHs AND METALS IN SURFICIAL SOILS

PAHs are ubiquitous and consistently present in the environment because they are typically formed during the incomplete burning of organic materials including wood, coal, oil, gasoline, and trash.  PAHs are also found in crude oil, coal tar, creosote, and asphalt.  Historically, PAHs have been associated with human activities such as cooking, heating homes, and fuel for operating motor vehicles.  Low levels of PAHs are also present in the environment from natural sources, such as forest fires.  The presence of PAHs in the environment at higher concentrations is usually an artifact of human habitation and is due to the widespread practice of emptying fireplaces, stoves, and boilers in rural and urban areas over the past several hundred years.  As a result, it is very common to detect “background” levels of PAHs in residential soils.

PAHs are a class of structurally similar chemical compounds characterized by the presence of fused aromatic rings.  PAHs are often discussed as a group because they are commonly found as mixtures of two (2) or more compounds in the environment.  There are over 100 chemicals in this family of compounds (although a smaller number are typically reported at a specific disposal site).  While PAHs are often discussed as a group, a risk characterization evaluates each chemical individually. The United States Environmental Protection Agency (USEPA) has classified seven (7) of the PAHs as probable human carcinogens.  PAHs not definitively classified as a carcinogen to date may still contribute to the overall carcinogenic risk posed by PAH contaminated soil and should not necessarily be assumed to be “non-carcinogens.”  Additionally, many of the PAHs not classified as a carcinogen, continue to represent a significant risk of harm to human health, safety, public welfare or the environment due to other toxicological effects they may cause.  The pathway of human exposure to elevated levels of PAHs in contaminated soil is generally through direct dermal contact or ingestion, but may also occur through the ingestion of vegetables grown within contaminated soil or leaching into the underlying groundwater.

Metals are both naturally occurring and found in man-made materials (such as paint, fuel, fertilizers and pesticides) widely distributed in the environment.  Naturally occurring metals present in wood and coal, are also often found concentrated in ash residue.  Specifically, elevated concentrations of the metal lead are often observed in surficial soil adjacent to residential structures constructed prior to the mid 1970s.  These elevated lead concentrations are primarily the result of the historical use of lead paint.  Lead poisoning is a disease caused when lead enters the body.  Lead can be adsorbed through the skin, swallowed or inhaled (breathed in).  Lead in the body can cause damage to the brain, kidneys and nervous system of young children.  Women who are pregnant can pass lead to the baby.  Even very low levels of lead can cause learning and behavioral problems.

Massachusetts General Law (M.G.L.) Chapter 21E and the Massachusetts Contingency Plan (MCP) do not require remediation of chemicals present at levels consistent with background, even if such concentrations would otherwise pose a significant risk of harm to health, safety, public welfare or the environment.  The MCP also exempts several other environmental conditions (such as lead from lead paint or engine emission and pesticides applied according to their label) that could pose a Significant Risk.

The MCP defines background as those levels of OHM that would exist in the absence of the disposal site of concern which are either:

1. Ubiquitous and consistently present in the environment at and in the vicinity of the disposal site of concern, and attributable to geologic or ecological conditions, or atmospheric deposition of an industrial process or engine emissions;
2. Attributable to coal ash or wood ash associated with fill material;
3. Releases to groundwater from a public water supply system; or
4. Petroleum residues that are incidental to the normal operation of motor vehicles.

While such conditions are not subject to the provisions of the MCP, the Massachusetts Department of Environmental Protection (DEP) encourages that potential exposures be mitigated whenever possible.  Such mitigation measures may include:

1. Providing clean soil (down to a depth of 3 feet) in residential settings; and
2. Providing clean corridors for subsurface utility lines.

SANITARY DISPOSAL SYSTEMS AND DRY WELLS

Many residential properties have on-site subsurface sanitary disposal systems or a dry well(s) associated with roof drainage.  Many older homes may also have an abandoned and/or out of service subsurface sanitary disposal system (which includes a leaching field or emanation chamber) or a dry well(s) historically used in association with the discharge from a washing machine, utility sink or garage floor drain.  The discharge of oil or hazardous material though a current or historical on-site subsurface disposal system or dry well may have contaminated soil or groundwater.  Sometimes this contamination can be significant and could pose a risk to indoor air at the property or migrate to an adjacent property or groundwater.  If you suspect that there may have been a subsurface release of OHM at your property or a property which you are considering purchasing, please feel free to contact LINEC with any questions you may have.