SEOUL, Dec. 18 (Xinhua) -- Three high school students were found dead, with seven others injured on Tuesday afternoon at a pension in northeastern South Korea, local media reported citing police and firefighters.
Among the 10 male students, all of whom attend a high school in Seoul, three were found dead and seven were unconscious at around 1:12 p.m. local time (0412 GMT) at a pension in the city of Gangneung in Gangwon province. Two of them were reportedly in critical condition.
The students were on an excursion after finishing their scholastic aptitude test for college entrance.
The cause of the incident was still under investigation, but the firefighting authorities were quoted as saying that the students vomited and foamed at their mouth when they were found.
The level of carbon monoxide concentration at the scene was 155 parts per million (ppm), much higher than the standard 20 ppm.
