DHAKA, Dec. 28 (Xinhua) -- Bangladeshi police has lodged a case against the owner and the labor contractors of a ship breaking yard at Sitakunda in South Asian country's southeastern Chittagongport city after an explosion aboard a scrap oil tanker killed four workers on Saturday.

    Quoting police at Sitakunda, some 242 km away of capital Dhaka,local news agency bdnews24.com Monday reported that the case was filed Sunday against Md Israfil, the owner of Rahim Steel and Ship Breaking Yard, and five labor contractors for failing to ensure safety of workers.

    The explosion aboard the out-of-commission oil tanker killed four ship breakers and injured 10 others in Sitakunda Saturday, it said.

    Sitakunda police chief Monirul Islam told bdnews24.com that a gas cylinder exploded at around 10:30 a.m. local time while workers were engaged in dismantling the ship.

    Ship breaking is flagged as a "Category Red," or "extremely hazardous" industry in Bangladesh, it said.

    Ship breaking yards in Bangladesh produces thousands of tons of scrap metal used by re-rolling mills, but serious concerns prevail over work safety as well as environmental standards, bdnews24.com said.

    Workers dismantle ships by hand without proper machinery, protective wear or training, it said, adding the yard owners also compel the beakers to take apart ships without clearing them of toxic materials.

    Earlier in October this year three workers of a ship-breaking yard at Sitakundu also died as an iron-plate fell on them while they were working at the yard Thursday morning.

    At least 1,000 workers reportedly died in the last 20 years in Bangladesh's ship-breaking yards excluding the deaths from diseases caused by toxic fumes and materials workers are exposed to all the time.

    Some 30,000 workers are engaged in 36 ship scrapping yards in Chittagong's Sitakunda, which houses the world's second largest ship-breaking industry after China.