[TheForge] Need help with a mystery odor in my house

[Bruce .]

Sorry, this is not blacksmithing related at all, but I'm about at my wit's
end and I know that this group includes lots of folks with varied
experience and good deductive skills.

Some background:  I live in a ranch-style home with full basement and
storage attic.  My garage (shop) is detached.  I have (detached) sheds out
back where I keep most fuels and much paint, including spray paint, so the
bulk of this is not in the house at all.

My back hall leads off the kitchen via a pocket door, which I usually keep
closed, and my back hall is down two steps.  The back door is then to the
right and the stairs to the basement are to the left, opposite the back
door.  The pocket door, then separates the back hall and basement from the
ground floor of the house.

At the bottom of the stairs is a small "foyer".  There's an (open) door to
the east half, where the gas appliances are located in a separate "laundry
room", and an (open) door to the west, that has a separate bathroom.  There
is a sewer ejector that serves the bathroom and the laundry, but its
contents are clean at present because I've been doing laundry but not using
the basement john.

As to possible odors:  There are some oil paints, spray paints, glues,
Brakleen, and other auto fluids in the back hall and basement.  My house
and water are heated with gas.  I have paint stored in the laundry room,
and glues and such stored in the east basement.  I have one bin of misc.
automotive fluids in the west basement.

As recently as yesterday I was all through the house and smelled no
particular odors anywhere.  This morning I opened the pocket door to the
back hall and  immediately noticed an odor that I'd describe as "oily."

I immediately checked all my gas appliances in the basement -- boiler,
water heater and clothes dryer -- spraying all valve cocks, pipe joints and
the flex hose to the dryer with detergent-water to look for leaks, and
found none.

As a reference, I also accumulated a bit of gas from my kitchen stove in an
inverted bowl and sniffed that.  The odor of the gas was not at all the
same "oily" odor I smelled in the back hall.

Next I sought out a closed plastic bin in the west basement that contains
various fluids for automotive use.  One of these had leaked a bit some time
ago, but the odor wasn't bad if I kept the bin sealed.  I opened the bin
and noted the odor was *not *the "oily" odor I'd been smelling in the
house.  Nonetheless, I hauled the entire bin out back and have left it
there since.

At this point, I was out of ideas.  In an excess of caution, I opened one
window near my basement gas appliances, opened all doors between there and
the ground floor, opened a window on the ground floor and put a wind-box
fan, set on "high", in the window, blowing outward.  Fortunately, the
weather was nice today, so I left it like this for a while, with air being
pulled through the house.  (The idea was both to vent the odor and to
prevent accumulation of an explosive mixture if the odor was from a
flammable compound.)

I went out from noon to 3PM, and when I returned the odor was present in
the house, but I don't recall it being strong.  At some later point I
turned the wind-box fan to "low", but I don't now recall whether this was
before going out or after returning.  I left again at about 7 PM, and
during this time I was dimly aware of the odor, but it did not strike me as
strong.  (Granted, the nose fatigues.)

When I returned around 10 PM I immediately smelled the odor when I entered
the front door.  Once again I checked all gas lines for leaks, and found
none.

This time I went through the various thing stored in the back hall,
carefully sniffing each, and none have the "oily" smell I'm experiencing.
(This included Brakleen, a permethrin spray, 30-weight oil, and maybe one
or two other things.  I know quite well what WD-40 and spray paint smell
like, so didn't try those.)  I also have sniffed some used crankcase oil
from a garden tractor (which I'm waiting to dispose of properly), some
kerosene, and some diesel fuel.  The kerosene is the closest to the "oily"
smell, but not exactly the same.  I associate the "oily" smell with auto
shops.  Maybe it smells like dilute used crankcase oil, but not quite like
that from that garden tractor.

At this point I'm fairly sure there is no gas leak, but I'm leaving the fan
in the window to pull air through the house anyway.  The odor was first in
the back hall, but may also have been in the basement.  At no time did it
seem to be concentrated around the basement gas appliances.  More likely it
was coming from the west basement, but that's not certain.  The odor is not
likely to be sewer gas, both for the type of odor and for it's origin, but
I've run some water in each basement drain to ensure the traps are filled.

The real puzzle is that I have absolutely no idea what this smell is or
where it's coming from.  I have no reason to believe that it's being pulled
in from outside.  I have no reason to believe I've been the victim of
mischief.    FWIW, my sense of smell seems normal.  Acetone, isopropyl
alcohol witch hazel, lavender, and  food (at dinner) all smell or taste
normal.

Any insights would be very welcome.

Bruce
NJ