CSB Releases Draft Investigation Report into
2009 Explosion and Fire at Caribbean Petroleum Terminal Facility in
Puerto Rico; Report Finds Inadequate Management of Gasoline Storage Tank
Overfill Hazard
Washington, D.C., June 11, 2015
The US Chemical Safety Board (CSB) has released its draft investigation report into
the 2009 massive explosion at the Caribbean Petroleum, or CAPECO,
terminal facility near San Juan, Puerto Rico; the draft report includes
proposed recommendations for addressing regulatory gaps in safety
oversight of petroleum storage facilities by the Occupational Safety and
Health Administration (OSHA) and Environmental Protection Agency (EPA).
The draft report was discussed at a CSB public meeting this afternoon
at the CSB’s offices at 2175 K Street, NW, Washington, DC. The meeting
was webcast and public comments were accepted. At the meeting the CSB previewed an excerpt from the upcoming video on the CAPECO incident entitled, "Filling Blind."
The 2009 incident occurred when gasoline overflowed and sprayed out
from a large aboveground storage tank, forming a 107-acre vapor cloud
that ignited. While there were no fatalities, the explosion damaged
approximately 300 nearby homes and businesses and petroleum leaked into
the surrounding soil, waterways and wetlands. Flames from the explosion
could be seen from as far as eight miles away.
CSB Board Member Mark Griffon said, “The CSB’s investigation states
that there are a number of shortcomings in regulations that cover
petroleum storage facilities. Facilities such as CAPECO, which store
large quantities of gasoline and other flammables, are not required to
conduct a risk assessment of potential dangers to the nearby community
from their operations.”
The CSB’s draft report is available on the CSB website, csb.gov.
On Wednesday, October 21, 2009, Caribbean Petroleum Corporation began a
routine transfer of more than ten million gallons of unleaded gasoline
from a tanker vessel docked two and a half miles from the facility. The
only storage tank that was large enough to hold a full shipment of
gasoline was already in use. As a result, CAPECO planned to distribute
the gasoline among four smaller storage tanks. This operation would take
more than 24 hours to complete.
During transfer operations, one CAPECO
operator was stationed at the dock, while another monitored valves
controlling gasoline delivery at the terminal.
By noon the next day, October 22, two of the tanks were filled with
gasoline. The operators then diverted the gasoline into two other tanks –
tanks 409 and 411.
At 10 pm the night of the 22nd, as tank 411 reached
maximum capacity, operators fully opened the valve to tank 409.
According to witness interviews, the supervisor on duty estimated that
tank 409 would be full at 1 am. But shortly before midnight, tank 409
started to overflow. Gasoline sprayed from the vents forming a vapor
cloud and a pool of liquid in the tank’s containment dike.
The CSB’s investigation found that the measuring devices used to
determine the liquid levels in the tanks at CAPECO were poorly
maintained and frequently were not working. The facility primarily
measured tank levels using simple mechanical devices consisting of a
float and automatic measuring tape.
An electronic transmitter card was
supposed to send the liquid level measurements to the control room. But
the transmitter card on tank 409 was out of service, so operators were
required to manually record the hourly tank level readings.
Investigator Vidisha Parasram said, “We found that the ‘float and tape’
measuring system was the only control system CAPECO used to avoid
overfilling a tank. When that system failed, the facility did not have
additional layers of protection in place to prevent an incident. The
investigation concluded that if multiple layers of protection such as an
independent high level alarm or an automatic overfill prevention system
had been present this massive release most likely would have been
prevented.”
The CSB report further explains that an independent high level alarm
could have detected and alerted operators to the danger of an overfill,
even if the primary system for measuring the tank level fails, as it did
at CAPECO. An automatic overfill prevention system goes even further,
and can shut off or divert the flow into a tank when the tank level is
critically high. These additional layers of protection, however, were
not used at CAPECO.
The CSB found that existing process safety regulations exempt
atmospheric storage tanks of gasoline and similar flammable liquids.
Additionally the report concludes current regulations only require a
single layer of protection against a catastrophic tank overfill –
thereby putting workers and nearby communities at potential risk.
The draft report would recommend that EPA adopt new regulations for
facilities like CAPECO to require that flammable storage tanks are
equipped with automatic overfill protection systems, and to require
regular testing and inspection as well as risk assessments.
The Board
is also recommending similar recommendations to OSHA, the American
Petroleum Institute, and two key fire code organizations. The proposed
regulatory changes would affect the EPA’s Risk Management Program; Spill
Prevention, Control, and Countermeasure (SPCC) rules; and/or OSHA’s
Flammable and Combustible Liquids standard.
The CSB is an independent federal agency charged with investigating
industrial chemical accidents. The agency's board members are appointed
by the president and confirmed by the Senate. CSB investigations look
into all aspects of chemical accidents, including physical causes such
as equipment failure as well as inadequacies in regulations, industry
standards, and safety management systems.
The Board does not issue citations or fines but does make safety
recommendations to plants, industry organizations, labor groups, and
regulatory agencies such as OSHA and EPA. Visit our website, www.csb.gov.