TAIYUAN, March 13 -- The death toll from a truck collision and resulting explosion in north China's Shanxi Province on March 1 has risen to 31, with nine others still missing, authorities said on Thursday.

The accident happened at 2:50 p.m., when two tankers loaded with methanol, a poisonous and flammable liquid often used as a fuel, rear-ended inside the Yanhou Tunnel of a highway linking Shanxi's Jincheng City and Jiyuan City in Henan Province.

The death toll was updated at a meeting in Jincheng City held by an investigation group sent by China's State Council.

Leaking methanol from the first truck caught on fire after the collision. The blaze spread through the tunnel, igniting 42 vehicles and their cargo, including coal.

Shanxi provincial government authorities paid great attention to the accident and sent an emergency rescue team to the site soon after the incident, according to a press release from the State Administration of Work Safety.

A joint investigation team approved by the State Council and headed by the State Administration of Work Safety has conducted an investigation into the accident.

Representatives from the Supreme People's Procuratorate were also invited to serve on the team.

An investigation found that the explosion damaged 42 vehicles in the tunnel, many of which were so badly burned that it has been difficult to confirm the number of deaths and conduct DNA identification of victims.

The meeting also stressed the importance of identifying victims and treating injuries.