Soil around 247 fuel storage facilities nationwide, including gas stations, was found to contain excessive levels of carcinogenic materials, the Ministry of Environment said Sunday.

The authorities examined the soil near 7,347 petroleum and natural gas production sites and petrol stations and other areas with underground or above-ground storage tanks.

It found 247 places, or 3.4 percent of the facilities, containing TPH and BTEX above government guidelines.

TPH, or total petroleum hydrocarbon and BTEX ― benzene, toluene, ethylbenzene and xylenes ― are known to have harmful effects on the central nervous system and increase the likelihood of cancer.

Excessive amounts of TPH were detected at 117 spots, while BTEX was found in 20 locations, and 110 places held large amounts of both TPH and BTEX.

Gyeonggi Province had the highest share of the polluted areas, with 50 sites. It was followed by Seoul with 38, South Chungcheong Province with 33, South Gyeongsang Province with 15, Busan with 12 and Gangwon Province with 12.

The government ordered the facilities to take steps to correct the situation.

By Bae Ji-sook (baejisook@heraldcorp.com)