An explosion ripped through a fireworks factory in northeast China early Monday, killing at least two people and leaving several missing.

Up to 50 workers were working at the factory in the city of Yichun in Heilongjiang province when it was rocked by a massive blast at about 9:40 a.m. (0140 GMT), according to a statement posted on the local government's website.

It said there were two confirmed deaths and that 22 workers were rescued. The fate of the remaining workers was not immediately known.

The blast was felt up to two miles (about 5 kilometers) away from the factory, and it smashed windows in the local government offices and other buildings, the statement said. Eyewitness' photos posted to the Internet showed plumes of smoke curled above the plant, and the government statement said secondary explosions were preventing rescue workers from entering the building.

Safety is lax at Chinese fireworks plants, and accidental blasts are common. Dozens of people also die each year from unsafe handling of fireworks used to celebrate weddings and traditional holidays.

In another industrial accident on Monday, an elevator plunged on a construction site, killing 11 workers riding in it.

Investigators were looking into the cause of the accident in the city of Meihekou in the northeastern province of Jilin. The elevator plunged by as many as 12 stories, according to a statement from the local government.

Although deadly accidents persist, China has placed an increasing emphasis on improving industrial safety.

Fatalities in the country's notoriously dangerous coal mines decreased to 2,631 last year, compared with a peak of 6,995 deaths in 2002, according to official figures.

That works out to 7.2 deaths a day in 2009, down from 19.1 a day in 2002.