Gas samples were taken in 87 public buildings, including some schools. (CBC)

Fewer than 10 per cent of samples taken in P.E.I.'s public buildings as part of a new round of testing for radioactive radon gas showed levels above Health Canada guidelines.

Health Canada lowered the acceptable level of radon from 800 becquerels per cubic metre to 200 in 2007. Last winter, P.E.I. carried out tests at 87 sites to determine if public buildings, including some schools, were meeting the new guidelines. Of 504 samples taken, 39 were found to exceed the new guideline. None of the samples exceeded the old guideline.

"The results show relatively low radon levels compared with those found in many other regions of Canada," deputy chief health officer Dr. Lamont Sweet said in a news release Wednesday.

"Since radon occurs from the natural breakdown of uranium in soil and rock, regions of Canada with higher concentrations of uranium than in P.E.I. soil could be subject to higher levels of radon."

Sweet said Island sandstone has relatively low levels of uranium. Regions with mostly granite terrain have relatively high levels.

During the summer, the 20 buildings that produced samples exceeding the new guidelines will be inspected to find areas where radon gas could be entering the building.

Inspectors will be looking at cracks in concrete floors, joints between foundation walls and floors, floor drains, sump pits and other areas that may allow the gas to seep into the building. Measures will then be taken to reduce radon levels by sealing or caulking any cracks, joints or entry points as much as possible.

The buildings will be retested next winter, when radon levels are typically highest. More buildings will also be tested, with all remaining Island schools done.