Outdoor above ground oil tank with leak stains at tank bottom (C) Daniel Friedman Oil Odors & Smells: odor sources traced to fuel oil, heating oil, oil storage tanks & oil piping leaks
Odor source diagnosis & repair - oil smells

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Sources of oil smells in or outside of buildings:

How to track down the source of an oil smell traced to fuel oil, heating oil, or even crude oil leaks from heating equipment, oil piping, or oil storage tanks. This article describes common sources of indoor or outdoor oil odors due to fuel oil, heating oil, or similar products.

A close look at the bottom of the outdoor above ground oil storage tank shown at page top shows what looks like oil seepage [click to enlarge]. We suspect this oil tank is leaking.

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Sources of Oil Smells Outdoors or Inside of Buildings

Photograph of a seepage leak at an oil tank filler pipe, wrapped with a ragHere is a catalog of places to look when tracking down smells of diesel fuel, fuel oil, heating oil, or other oil products.

[Click to enlarge any image]

Heating or Fuel Oil Spills During Oil Storage Tank Fill-Up

While usually oil delivery drivers are quite careful, on occasion there may be some spillage around the fill of an oil storage tank occurring during tank fill procedures.

Look for oil stains on the ground around the fill or vent piping for both above ground fill and vent pipes and at the fill and vent pipes for buried oil tanks. If you see an oil spill contact your heating oil company to request cleanup help.

The reporting of fuel oil and heating oil spills of this nature may be required by federal or state laws.

Heating Oil Storage Tank Fill or Vent Pipe Leaks

It is very common for there to be leakage around the oil filler pipe or vent pipe where they are connected to the top of an oil tank. If the tank is buried these leaks may go undetected for some time, but on an above ground oil tank, inside or outside, the seepage is quickly visible and also can be smelled by most owners shortly after an oil delivery.

Details are at OIL FILL / VENT PIPE LEAKS.

Usually an oil storage tank is filled right to its top during an oil delivery. This is because the way that the delivery driver knows that the tank is full is that s/he is (supposed to be) listening at the filler pipe.

If the oil delivery driver is not listening to the tank whistle or tank alarm, or if the tank top fittings are not absolutely tight, it is common to see some leakage around the oil tank top after a fill-up.

(Also see Oil Tank Pressures for an explanation of the stresses on oil tanks and piping during fill-up. Photograph of a small heating oil leak at a tank fire-o-matic safety valve at the tank bottom

If you see oil on the floor, check the bottom of the tank, sides and welded seams, and be sure to check the oil lines to the boiler and in particular, check the oil tank safety valve or other tank bottom fittings as there are often leaks at these valves, as shown in this photograph.

Before addressing tank top filler pipe fittings as a leak source, make sure the oil leakage is from the top of the oil tank and not from a tank seam or tank rust perforation (check the tank bottom).

Make sure that you know where the seepage is coming from. There may be separate spillage outside at the filler pipe from that occurring inside at the tank top or other fill or vent pipe fittings.


Heating Oil Piping or Valve Leaks

Photograph of copper piping used for an oil tank fill and vent pipe Photograph of  an oil tank with seepage around the filler pipe and a too-small vent pipe.

Make sure that the oil fill, vent, and fuel delivery piping is proper in material (steel is safer against rupture than plastic), and in diameter (2" or larger) for both vent and fill pipes.

The soldered copper fill and vent piping at the oil tank in the photo at above left was unusual and may not be permitted. At the top of this page, the silver-colored (galvanized steel) oil tank vent pipe in the tank is probably too small for modern tank fill methods.

An older-installed small diameter vent or fill pipe [photo at above right] top risks over pressurizing the tank during fill-up, and risks a costly oil spill should an old tank or fill or vent line rupture. Ask your oil company to review the condition of the piping and the condition of the tank.

If the seepage is trivial in amount, say simply a light stain just a few inches around the tank top, clean it off and live with it. Or more properly, re-make the pipe joints when other plumbing work is planned. (It's quite a bit of trouble to re-make these joints, especially if the filler and vent piping have been routed through and cemented into a masonry wall.)


Photograph of severe seepage leaks at all top fittings of a heating oil storage tank

If the seepage is enough to wet the tank or run down the whole tank and drip onto the floor this is an unacceptable condition that needs correction.

It's likely that the piping will have to be removed and (possibly new) piping installed.

I am doubtful that any "band-aid" approach like pushing epoxy putty or other sealers around the existing fitting is going to work. The surfaces will be rough, rusty, and oily.

If a reader or product manufacturer has a sealant that is actually effective in this application, dealing with the rust, oil, surface shapes, and fill pressure, I'll be glad to report on that product here. It would indeed be less trouble than re-piping the tank. Make sure the new piping is properly sealed and secured.

If heating oil has been dripped on the floor, ask your oil company to clean it up and deodorize the area.

Actual Leaks in a Fuel Oil or Heating Oil Storage Tank

Photograph of a basement heating oil storage tank leak onto the concrete floorLeaks at an oil storage tank may not only produce a smell, but are likely to involve significant cost to clean up spilled oil if a significant leak occurs, especially a below-ground leak. We discuss leaky oil tanks beginning

If an oil storage tank is leaking federal (and most state) laws require that the leak be reported to your local department of environmental conservation or environmental protection.

Actual heating oil spills:

If there is an actual oil spill, indoors or out, most state departments of environmental protection require that they be notified within 24 hours of the spill, an inspection is performed, and an expert specifies the amount of cleanup needed.

Leaks also occur or may have previously occurred at abandoned oil tanks in locations that can give off oil odors.

Heating oil leak through foundation wall (C) Daniel Friedman Heating oil leak through foundation wall (C) Daniel Friedman

Our two photos above illustrate heating oil leaks seeping through the building foundation wall from an outside oil storage tank leak. Because of the depth of the seepage points in the foundation wall (mid-wall at left, wall bottom at above right) and because there was no oil storage tank visible above ground at these locations, we suspected that a buried oil storage tank had previously leaked close to the foundation wall. Further investigation was needed. Also


Oil Odors Traced to Heating Equipment Malfunction

You may be smelling un-burned heating oil or fuel oil if the heating equipment is not working properly. A simple sniff test at the heating equipment may not be enough. Watch the equipment during start-up and shut down cycles, observing puffbacks, odd noises, or of course visual leaks around the equipment that occur during operation or when oil fired heating equipment is idle.

Keep in mind that in buildings heated or cooled by forced air, air ducts may transport odors from one building area to another.

Watch out: a mistake as simple as too little combustion air will produce a smoky flame and heating oil or fuel oil odors at and around oil fired heating equipment.

Oil Smells Traced to Nearby Diesel Fuel Stations, Automotive Repair Shops, or Diesel-Fueled Equipment

Used oil storage tanks at an automobile repair facility (C) Daniel FriedmanA nearby diesel fuel station or diesel fueled equipment may also be a source of fuel oil smells outdoors even if no actual leaks or spills are present.

Our photo (left) shows a used oil collection tank that was not leaking at the time of our site visit. But at other automotive repair shops we occasionally see careless oil spills by workers or even by customers who drop off used oil for reclamation.

On occasion we observe diesel smells and even small leaks where diesel fueled equipment such as a backhoe or bulldozer is left parked.

Oil Smells Traced to Oil Pipelines or Piping

Oil odors may be traced to underground (or above ground) oil piping both from remote or curbside oil storage tank fill pipes used at some properties and even to oil pipelines that traverse properties.

In 2013 the New York Times reported that oil odors at a farm near Tioga, Colorado were traced to a small 1/4" sized leak in an oil pipeline crossing the property. While oil companies monitor pipelines for evidence of leakage and are expected to respond promptly to any leak, some pipeline sections are not required to have oil leak monitoring nor pressure sensors sufficient to detect small leaks. In cases such as the one reported by the Times, a small oil leak may continue for weeks without detection. [7]

The Pipeline and Hazardous Materials Safety Administration (PHMSA) is the U.S. federal pipeline agency, operating under the Department of Transportation (DOT) is responsible for overseeing the national pipeline system, while the U.S. DOT Office of Pipeline Safety (OPS) administers the national regulatory program to assure the safe and environmentally sound transportation of natural gas, liquefied natural gas and hazardous liquids by pipeline. - Wikipedia retrieved 10/25/2013

Really Stupid Sources of Oil Odors

Perhaps the stupidest source of an oil smell tracked down at a residential property was a New York property that included an abandoned water well.

The six-inch casing of the well protruded 18" above ground level close to a driveway.

When we smelled oil along the drive and asked the tenant what was going on he explained that he had been disposing of his used motor oil by "dumping it down into that old pipe"! Here was another good argument for properly sealing and capping an abandoned water well.


Continue reading at OIL LINE PIPING LEAKS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.



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