Narrator: On January 11, 2006,
an explosion and fire erupted at the Bethune Point Wastewater Treatment Plant
operated by the City of Daytona Beach, Florida. Two workers were killed and
a third was gravely injured. The explosion occurred as the
workers used a cutting torch above a storage tank containing highly
flammable methyl alcohol or methanol. The U.S. Chemical Safety Board
investigated the accident and issued a report with
findings and safety recommendations. The Bethune Point facility
employs eleven full-time workers and treats 13 million
gallons of wastewater a day. Methanol is used as an additive in
the wastewater treatment process. Merritt: The CSB found this tragedy occurred because
the city did not have a program to control hot work, that is, activities such as welding and cutting
that can ignite flammable materials. Furthermore, the city did not adequately train the workers
on the flammable and explosive hazards of methanol. Hall: Our investigation revealed that
flaws in the engineering design and maintenance greatly
increased the severity of this accident. The animation that follows is
based on the evidence we collected. On the day of the accident,
three workers were removing a hurricane damaged steel roof at the
Bethune Point Wastewater Treatment Plant. The roof covered two
chemical storage tanks; one empty, the other containing about 3,000
gallons of methanol, a highly flammable liquid. Two of the workers were
up in a man-lift basket where they were using an oxyacetylene torch
to cut the roof into sections. The third worker was operating a crane
to lower the roof sections to the ground. Beneath them, methanol vapor, which is
invisible but colored grey here for illustration, was venting from the top of the tank as
the morning sun warmed the liquid inside. As designed, the tank vented the
methanol vapor through a flame arrester, a simple device intended to prevent the contents
of the tank from being ignited by a fire outside. As the workers cut the roof, sparks
from the torch showered down onto the tank. The sparks ignited the methanol vapor, creating a
fireball under the two workers in the open man-lift basket. The fire flashed into the flame arrester,
but it was badly corroded and it failed to function. Flames spread instantly into the tank,
igniting the methanol inside. The force of the explosion from the
methanol air mixture inside the tank was so great, it rounded out the tank bottom
and lifted the tank walls. The blast ejected the level switch
and flame arrester from the tank. Plastic piping connected to the tank
fractured as the tank lifted and deformed. Methanol, under pressure from the explosion, spewed
from the broken pipes and ignited, spreading the fire. Methanol from broken pipes sprayed the crane cab,
caught fire and burned the worker inside. He died from his injuries
the following day. Burning methanol vapors flowed out of
the open vent on the top of the tank. In the man-lift basket,
both workers were now burning. One jumped or fell
from the basket and died. The other worker escaped by climbing onto the roof,
jumping to a lower roof and then to the ground. He was gravely injured, but survived
after many months in the hospital. Hall: The CSB found that some of the causes
of this accident could be traced back to 1993 when the methanol tank was installed. These include problems with the flame arrester
and the use of plastic piping on the tank. Narrator: CSB investigators that the
flame arrester plates were made of aluminum, which is readily corroded by methanol. These plates are designed to allow
vapors to vent safely from the tank. In case of fire outside the tank,
the plates cool and extinguish flames and prevent them from igniting
the flammable methanol inside. In this case, the plates were so corroded,
they were incapable of quenching the flames. This corrosion could have been
detected through regular inspections, yet the CSB found that the city was not
aware of the need to inspect the flame arrester and had not done so since its
installation 13 years earlier. Selk: Plant managers should verify that
critical safety devices, such as flame arresters, are regularly inspected and maintained. Facility designers should ensure that proper materials
are specified for pipes carrying hazardous liquids. Selk: The engineering company that designed the Bethune
Point methanol storage system, Camp, Dresser and McKee, specified that the piping and valves
be made of PVC plastic, not steel. Steel is stronger and tougher than PVC. Had steel piping been used, it likely
would have remained intact during the explosion and the resulting fire
would have been less severe. Selk: Worker training was another important
issue identified in the CSB’s investigation. Bethune Point workers could not recall ever
receiving any training on the hazards of methanol. In fact, the employees only
received a total of about one hour of safety training in each of the
two years preceding the accident. Barab: Florida law does not
require state or local governments to provide public employees with safety training
or to comply with OSHA safety standards if public employees may face workplace hazards
similar to those found in the private sector where compliance with
OSHA standards is mandatory. Florida had a health and safety program for
public workers, but it was eliminated in 2000. In addition to Florida, public workers in 25
other states also are not covered by OSHA regulations, though some are covered
by voluntary programs. Merritt: OSHA regulations require among other things
chemical hazard training and hot work programs, which could have prevented
the explosion at Bethune Point. To prevent future accidents, the Board
made recommendations to the State of Florida, the City of Daytona Beach
and to others. Merritt: The CSB recommended
that Florida enact legislation to require workplace health and safety programs
for all public employees in the state, including chemical safety standards
at least as effective as OSHA. We recommended that until
state laws are in place, the City of Daytona Beach adopt health
and safety ordinances to cover its workers. We also made recommendations to the
National Fire Protection Association and to OSHA that would further restrict the use of
plastic in piping systems for flammable liquids. Merritt: The tragedy at the wastewater plant
could have been prevented, had the City followed the same safety standards
required of private employers. Workers in private industry benefit from a variety of
OSHA standards designed to prevent deaths and injuries. Public sector employees deserve no less. Thank you for watching
this CSB Safety Video. Merritt: For more information about the
Bethune Point accident or other CSB investigations, please visit our
website at CSB.gov.