The huge explosion that cost the life of at least 39 people in and around Venezuela's largest oil refinery, Amuay, is not an isolate accident. Since Chávez sacked in 2003 over 2000 PDVSA employees maintenance and security levels dropped dramatically. It doesn't matter PDVSA now has over 135% more workers than before.
March 2011 saw already an explosion in Amuay....there weren't dead back then but there were fatal casualties in that refinery in that year.
Alejandro Tarre has a good overview of the issues with regards to accidents and lack of maintenance in PDVSA since Chávez is in power.
As he says, Primero Justicia (Henrique Capriles' party) has kept track of 77 deaths related to PDVSA accidents since 2003. PDVSA's very 2011 annual report conceded it carried out only 2 out of 9 required maintenance procedures for that year.
Venezuela's refineries are a complete mess. Venezuela has to import more and more petrol than ever in spite of all the crude it has.