Four people have been killed and 33 injured in a gas explosion in the northern Iraqi city of Duhok. A student and a senior police officer were among the victims of Monday night's blast in a bakery above a student residence, governor Ali Tatar told local media. The police officer and another emergency worker died while trying to rescue students in the building. Several people are in a critical condition and the death toll is expected to rise, the authorities said. It comes just days after <a href="https://www.thenationalnews.com/mena/iraq/2022/11/18/six-killed-and-16-wounded-in-gas-tank-explosion-in-northern-iraq/" target="_blank">15 people were killed</a> in a gas tank explosion in the city of Sulaymaniyah. Both cities are in Iraq's semi-autonomous Kurdish region. Kurdistan Regional Government Prime Minister Masrour Barzani has suspended the use of gas systems in Erbil province while the cause of the blasts is being investigated, local media reported on Tuesday morning. Students housed in the building have now been moved to hotels, Mr Tatar said. Such accidents are relatively common in Iraq, where safety standards are poor and regulations often broken. Gas heaters often cause deadly fires in refugee and displacement camps dotted across the north of the country, where many people live in overcrowded and highly-flammable tents. In October, <a href="https://www.thenationalnews.com/mena/iraq/2022/10/30/nine-people-killed-in-baghdad-gas-tanker-explosion/" target="_blank">nine people died</a> in a gas tanker explosion in Baghdad. Fires have also claimed hundreds of lives in Iraq's south. More than 90 people died in a <a href="https://www.thenationalnews.com/mena/2021/07/13/iraqis-mourn-nasiriyah-hospital-fire-victims/" target="_blank">fire at a hospital</a> in the southern city of Nasiriyah in July last year, the second deadly hospital blaze in the space of a few months. That fire, said to have been caused by an oxygen tank explosion, stoked public anger at the authorities, which have long been accused of mismanagement and corruption. Safety standards in Iraq's construction industry are also often neglected. More than 30 people were injured in a <a href="https://www.thenationalnews.com/mena/iraq/2022/11/06/baghdad-building-collapse-injures-at-least-32-people/" target="_blank">building collapse</a> in Baghdad last month.