SEQUIM — Residents in Sequim soon will see “smoke” rising from unusual places, including the streets and the ground, street gutters, and possibly even from house vent piping.

Beginning sometime during the first two weeks of August and continuing through September, the Sequim Public Works Department will use a smoke-like substance to test city sanitary systems to find defects, breaks, leaks or faulty connections.

“This is the first time we’ve done it,” said Pete Tjemsland, utilities manager for the city.

The “smoke,” also known as petroleum hydrocarbon oil, is used in smoke blowers from Cherne Industries Inc. of Minneapolis, Minn., for sewer testing, according to information the city’s Public Works Department provided on its website, http://tinyurl.com/bmtdp49.

The city said it has no odor, is non-toxic, non-staining, does not create a fire hazard and will dissipate within a few minutes.

It can, however, cause coughing. The irritation is temporary and should disappear after exposure has ceased, the city website said.

Those with respiratory problems or mobility limitations can contact Tjemsland or the Public Works department for more information.

Each neighborhood and individual properties will be notified in advance when smoke testing will take place, Tjemsland said.

Bright pink door hangers will alert residents when testing will begin in their vicinity.

Green and blue A-frame board signs also will be placed in neighborhoods before testing begins, Tjemsland said.

Crews will open manholes and use a large engine to pump the material into the sanitary pipes, which are 50 years old in some places, he said.

The smoke will reveal defects in pipes — and may also show illegal connections, he said.

During the tests, residents may see smoke coming from vent stacks on buildings or from holes in the ground such as manhole covers, storm drains and building foundations.

“If residents see smoke, there is no need for alarm,” Tjemsland said.

Public Works recommends that residents flush toilets and run water down sinks, tubs and laundry drains before the first day of testing to make sure drain traps are blocked with water to prevent smoke from entering building.

If residents see smoke in their buildings, they should open doors and windows to ventilate the premises and consult a licensed plumber to identify how the smoke is entering the building, the city said, as the potential exists for sewer gases to enter in the same manner.

Residents who see smoke in their home who did not receive a flier or door hanger and have no signs in their neighborhood, should call 9-1-1.

Residents are welcome to ask questions of Public Works employees conducting the test in their neighborhoods.

The Clallam County Fire District, 9-1-1 Dispatch and Sequim Police will be notified of the testing, and locations will be updated throughout the test period.

To contact Tjemsland, phone 360-683-4908 or e-mail at sewersmoketest@sequimwa.gov.

Reporter Arwyn Rice can be reached at 360-452-2345, ext. 5070, or at arwyn.rice@peninsuladailynews.com.