THE EXPLOSIVE DANGER OF THE ASPHALT
FUMES – A REMINDER AFTER THE ASPHALT TANK EXPLOSION AT LA CROSSE, WISCONSIN
Over a half-million workers are exposed to fumes from asphalt,
a petroleum product used extensively in road paving, roofing, siding, and
concrete work. Health effects from exposure to asphalt fumes include headache,
skin rash, sensitization, fatigue, reduced appetite, throat and eye irritation,
cough, and skin cancer.
We would like to
remind you of some of the safety practices that need to be followed when
storing, handling, heating, and spraying liquid asphalt products. First, it must be recognized that all asphalt
products, when heated enough, are flammable. That means that if you heat any asphalt hot
enough, whether it is a cut back, an asphalt cement, or an emulsion, hazardous
vapors will be produced.
When these
vapors are mixed in proper proportion with oxygen in the air, and come in
contact with a source of ignition, a flash fire can occur. The flash may be quite violent, and if enough
vapors are present a raging fire may develop. These types of fire can and have
burned people very badly, and have killed some.
Many of the asphalt
products we use every day are used at temperatures above their flash points. The flash point is the product temperature
where a source of ignition will cause the vapors produced to catch on fire. RC and MC cut back asphalts are commonly used
at temperatures above their flash points, where flammable vapors are produced.
The flash points of asphalt cements may be above the temperatures at which they
are used, but they are not far away. You may be using an asphalt cement (AC) at
a temperature which is only 20 to 25°F below its
flash point. If that AC is overheated in a small area, flammable vapors may be
produced. If the water is boiled off of
a bit of emulsion, the remains may be asphalt cement or there may be solvents in
the asphalt which can produce flammable vapors. In either case the remains are dangerous if overheated.
You may overheat a small amount of emulsion, boil off the water, overheat the
remaining asphalt, and be producing flammable vapors without even realizing it.
If the vapors mix with oxygen and reach
a source of ignition, a fire will develop.
The flammable
nature of asphalt vapors, and the quick, violent fires which can develop lead
us to recommend the following safety precautions.
When
heating asphalt in a transport tank, distributor, or tack truck, position the
tank broadside to the wind
If any flammable
vapors are present, the vapors must escape from the tank through the vent pipe.
Typically the vent pipe exits at the bottom of the asphalt tank. Positioning
the tank broadside to the wind will allow the wind to disperse the vapors safely
away from the burners and other sources of ignition on the truck. If the tank
is parked facing into the wind or with its back to the wind, the wind may carry
vapors to the burners at the rear, or to other sources of combustion near the
engine. If you heat the asphalt tank in a confined area flammable vapors can
collect in combustible concentrations.
Always be
sure that the heating flues are covered by at least six inches of asphalt
before lighting the burners
If the heating
flues are not sufficiently covered, the asphalt near the flues will be
overheated. Flammable vapors will be
produced. ACs will be heated above their
flash points. Emulsions will be broken and
heated above the flash point of their base asphalt. The flue pipe may be heated hot enough to provide
a source of ignition. When this happens, an explosion can occur, which may
rupture the tank or blow the man hole cover off. Before lighting the burners it is very
important to be sure that the flues are covered over their entire length. Many
asphalt tanks are built with a slope or pitch for better drainage. If the tank
is parked on a grade, one end or one side of the tank may be higher than the
other. You must be sure that the highest point on the flue is covered according
to the equipment manufacturer’s recommendation.
Never, under any
circumstances light the burners without the flues covered to the depth
recommended! If the tank is partially loaded you may need to add more asphalt
before heating.
Never
spray asphalt while the burners are running
If you spray
asphalt with the burners running, you may uncover the flue causing a fire
inside the tank. Running the burners while spraying will provide a source of
ignition for vapors produced while spraying, causing a fire outside the tank.
Be sure the burners are completely out before spraying.
LPG burners will
support a flame for several minutes after the valves are shut off.
Keep all
sources of ignition away from manholes and tank vents
When you open
the manhole flammable vapors may escape. There may be flammable vapors in the tank
which are too concentrated to burn. When you open the manhole fresh air or
oxygen is introduced. The cigarette in
your hand becomes a source of ignition and you may be additional fuel.
Flammable vapors are intended to escape out of the tank vent. Keep hand
torches, cigarettes, engine exhaust, and other sources of ignition away from
these vapors.
Keep vent
pipes clear and open
Keeping the vent
pipe clear and open will allow the vapors to escape and will keep them from
building pressure inside the tank.
Do not
operate or weld on a tank which is leaking
A leaking tank
must be repaired before continuing use. The repair should be performed by an
experienced tank repair shop. An “empty” tank may contain flammable vapors or
residual asphalt. You would never consider welding on a gasoline tank. You
should never consider welding an asphalt tank either. A tank repair shop will
have sensors which can determine if there are flammable vapors present and if
the tank is safe to weld.
The hazards
identified are very real and very dangerous. Do not take these hazards lightly,
as you will see from a small sampling of the asphalt tank explosions or fires
that have happened over the years.
Accident:
201345337 - Two Employees Are Injured In Asphalt Tank Explosion
At approximately 7:45 a.m. on May 12, 2010, Employee #1, the
senior maintenance member of a two-man crew, and Employee #2 were working from
an elevated work platform. The platform was mounted on the back of a trailer,
which was mounted to an asphalt tank. The employees had begun bypassing the
normal asphalt storage tank to prepare for its five-year to seven-year
cleaning. They placed a bypass valve in position to route the asphalt from the
permanent tank to the temporary, trailer-mounted tank. Most of the asphalt
piping was heated with a steam jacket encircling the pipes.
However, the piping
that ran from the bypass valve to the temporary tank was encircled with tubing
that was heated by steam. The employees complained that the steam tubing, also
referred to as steam tracing, was not wrapped tight enough, thereby preventing
the pipe from getting hot enough to turn the hardened asphalt back to its
liquid (melted) state. The employees then attempted to repair the clogged pipe.
As was reported to be the normal practice, Employees #1 and #2 went to the end
of the asphalt piping outlet and began heating the last bend of the piping with
a propane torch. The piping outlet was located directly over the top of the
manhole opening of the heated asphalt tank. The tank was reported to be 300
degrees to 400 degrees Fahrenheit, at that time.
During the site visit,
approximately five hours later, the tank temperature gauge read approximately
260 degrees Fahrenheit. After an undetermined amount of time that Employees #1
and #2 were using the propane torch to heat the piping, an explosion occurred
in the asphalt tank. A witness described the explosion as a flame which shot 30
feet above the manhole cover and quickly descended back into the tank. This
witness also stated that he could no longer observe the employees standing on
the platform. Employee #1 remained on the platform and suffered asphalt burns
and fractures to his face, where an item impacted it during the explosion.
Employee #2 fell from the work platform, approximately 9 feet 5 inches to the
concrete surface.
Employee #2 suffered asphalt burns to his body and face, in
addition to a hip fracture. A radio call for emergency response was broadcast
throughout the company. The company Emergency Response Team doused the flames
and provided initial first aid to Employees #1 and Employee #2. Both employees
were transported to the University of Kansas Burn Unit and were hospitalized.
At the time this report was written, they were currently being treated. Both
employees were in critical but stable condition and were expected to recover.
The safety leader stated that Employees #1 and #2 were wearing coveralls, steel
toed shoes and safety gloves. However, they did not find evidence that the
employees were wearing face shields and/or chemical goggles, as called for in
the PPE hazard assessment
Worker
dies in explosion of tank at asphalt plant
January
30, 2006
WEST SIDE
— An explosion at a Chicago asphalt company Sunday killed one worker.
The
explosion occurred just after 1 p.m. Sunday at Gardner Asphalt Corp., 4718 W.
Roosevelt Rd., where one of four outdoor tanks caught fire, said Kevin
MacGregor of the Fire Department.
The nearly
30-foot-tall tank most likely contained asphalt, which ignited for an unknown
reason, MacGregor said, adding that firefighters prevented the other tanks from
catching fire.
"We
will be doing an investigation for cause and the origin of the fire," he
said.
The
worker, who was pronounced dead at the scene at 2:35 p.m., was not publicly
identified because his family had not been notified, said a spokesman for the
Cook County medical examiner.
No one at
Gardner was available for comment Sunday.
Asphalt tank in Jessup explodes
January 31, 2006
A liquid-asphalt storage tank exploded into flames at an Owens
Corning shingle plant in Jessup yesterday evening, drawing dozens of
firefighters from Howard, Anne Arundel and Prince George's counties to prevent
the blaze from spreading to adjacent tanks. There were no injuries.
The cause of the blaze on the grounds of the
Baltimore-Washington Industrial Park, off U.S. 1, could not be immediately
determined, said Bill Mould, a spokesman for Howard County's Department of Fire
and Rescue Services. The fire was reported at 5:33 p.m. and was declared
contained about two hours later. But firefighters planned to stay to monitor
the situation throughout the night.
"There was an explosion and the roof continued to
burn," said Jason Saragian, a spokesman for Owens Corning. "How and
why is still the focus of the investigation."
Aerial tower trucks were used to pour water onto the nearby
tanks of liquid asphalt, which is used to make roof shingles. Plumes of black
smoke filled the air, and the exterior of the 3,300-gallon asphalt tank
appeared to be on fire.
Fire officials said they did not put water directly on the
blaze for fear of bursting the tank. Instead, they sprayed water on the
exterior to keep it cool. A chemical powder, typically used for aircraft fires,
was brought from Baltimore-Washington International Thurgood Marshall Airport
to help extinguish the fire.
The fire erupted in an industrial area in the 8200 block of
Patuxent Range Road. No homes are in the immediate vicinity. Officials from the
Maryland Department of the Environment were on the scene, assessing the risk
from runoff and smoke.
Too Much Pressure in Storage Tank Blamed For Bango Oil
Explosion
Updated: Wed 9:23 PM, Jan 08, 2014
FALLON, NV
- It was nearly one month ago that an explosion and fire rocked the Bango Oil
plant west of Fallon, sending a thick plume of black smoke into the chilly
morning air.
One worker
was severely burned.
It took
firefighters from Churchill County and the Fallon Naval Air Station two hours to
extinguish the flames.
A
preliminary report from the investigation by the fire department and the state
fire marshal's office released Wednesday says it all began with too much
pressure in an asphalt storage tank.
Churchill
County Fire Chief Fred Rogne says that led to some of the hot asphalt oil being
vented from the top of the tank.
The oil
splashed down on 24 year old Daniel Snodgrass who was working below. The oil,
which had been heated to 500 degrees as part of the recycling process, burned
him.
Snodgrass
was apparently heating pipes in the bitter cold, using a hand held burner with
an open flame.
That flame
ignited the oil, causing the fire and the explosion that followed as the tops
of storage tanks blew off as they're designed to do.
The
statement leaves some questions unanswered including the still unexplained high
pressure in the storage tank. In a press release issued the day after the
incident, the company says the plant was operating normally at the time.
The
Occupational Safety and Health Administration is conducting its own
investigation. Results could be available in two weeks.
Snodgrass
suffered second, third and fourth degree burns over more than half of his body.
He was
flown to the burn center at UC Davis Medical Center in Sacramento in critical
condition.
A hospital
a spokesperson tells us he's now listed in good condition meaning his vital
signs are stable and indications are excellent.
His
parents, Kevin and Lois Snodgrass, say he has good days and bad, but is
enduring a daily routine of painful treatment and rehabilitation.
Daniel
Snodgrass is the oldest sibling in a family of nine which now faces months of
unexpected expenses.
An account
has been set up to aid them. Donations can be made at any Wells Fargo Bank
branch.
Fatal Explosion Brings Framingham Employer OSHA Citations
HARTFORD
-- A July 3 explosion of an asphalt tank at a Framingham, Mass. company that
killed a worker could have been prevented if the company had taken the proper
safety precautions, according to the U.S. Labor Department's Occupational
Safety and Health Administration (OSHA).
As a result of the agency's investigation
of the fatal explosion, OSHA has issued citations alleging willful and serious
safety violations to Triram Corporation of 721 Waverly St., including proposed
penalties totaling $52,500.
The investigation revealed that a
contractor was directed to do welding work on top of a 10,000-gallon tank
without being told about the tank's volatile contents.
"This was a tragedy that could have
been avoided," said Richard Fazzio, OSHA's area director for northeastern
Massachusetts. "The company should have followed required safety
procedures and informed workers about the dangers of the hazardous materials in
the workplace."
The alleged "willful" violation,
which carries a proposed penalty of $35,000, charges Triram Corporation with
failing to implement a hazard communication program. The company did not inform
the welding contractor about hazards related to flammable vapors produced by
heated asphalt and chemicals in the tank being welded.
The company is also charged with five
alleged "serious" violations of OSHA safety standards for: failing to
ensure containers of hazardous chemicals were labeled with proper contents and
hazard warnings; failing to assure that containers of toxic or flammable
substances were either filled with water or cleaned thoroughly and vented and
tested prior to welding, cutting or heating; failing to equip above-ground
storage tanks with a pressure release device; and exposing employees to fire or
explosion from a tank that stored flammable liquid adjacent to a main building.
Proposed fines for these alleged violations total $17,500.
OSHA defines a willful violation as one
committed with intentional disregard or plain indifference to the requirements
of the Occupational Safety and Health Act and regulations. It defines a serious
violation as one in which there is substantial probability that death or
serious physical harm could result, and the employer knew, or should have
known, of the hazard.
Triram Corporation has 15 business days
from receipt of these citations to either elect to comply with them, to request
and participate in an informal conference with the OSHA area director, or to
contest them before the independent Occupational Safety and Health Review
Commission. OSHA's Methuen area office conducted this inspection. Its telephone
number is 617-565-8110.
The Occupational Safety and Health
Administration is dedicated to saving lives, preventing injuries and illnesses,
and protecting America's workers. Safety and health add value to business, the
workplace and life. For more information, visit www.osha.gov.
Accident: 550509 - Employee Dies In Explosion After Using
Torch On Asphalt Tank
Employee #1 was directed to use an open-flame propane torch to
unclog a pipe line/elbow on top of an asphalt tanker trailer. The pipe
line/elbow was blocked with solidified asphalt. The blockage was suspected to
be located at the pipe elbow on the gasoline-powered submerged pump. The
employee checked the side motor mount area with a live, open-flame propane
torch while the internal asphalt tanker heaters were operating (heating the
asphalt and creating off-gassing within the tank's interior). It is suspected
that the torch ignited combustible vapors/gases that were seeping out around
the motor mount. The explosion blew the submerged pump off its mount and into
the employee's upper body and head. The employee was blown off the platform and
landed on the ground. He was burned over his upper body by the flash fire. He
was pronounced dead upon arrival at a local hospital.
Employee Killed, Others Injured In Asphalt Tanker Explosion
Accident: 14333595 -- Report ID: 0420600 -- Event Date:
05/11/1992 - Florida Tank Services, Inc.
Employee #1 was at an establishment that repairs bulk fuel
transport trucks, repairing a small leak on the rear bulkhead of an aluminum
tanker that had last contained an asphalt emulsion. Employee #4 was assigned as
his helper. Other welders recommended opening and venting the tanker and then
entering the tank to repair the leak from the inside. The company had no
specific procedures for "safing" asphalt tankers, and Employee #1
apparently chose to try to repair the leak from the outside. Once the tanker
was backed into the workbay, Employee #1 attempted the repair with an arc
welder. The repair failed because of product contamination around the leak.
Employee #1 then lowered the tanker at the front to force the remaining product
to the front and away from the leak, and used an oxygen/acetylene torch in an
attempt to melt the asphalt emulsion away from the leak, but did not open the
top hatches and vent the tank. An explosion occurred and Employee #1 suffered
fatal head injuries. Employee #4, who was next to the tanker, was knocked to
the floor and suffered from ringing in the ear, dizziness, and headaches from
inhalation of asphalt fumes and smoke. Employee #2 sustained bruises to his
ribcage when thrown into a work bench by the explosion. Employee #3 sprained
his left knee when the explosion knocked him from the top of a nearby tanker.
The building was heavily damaged and the tanker was destroyed. Causal factors include:
a lack of established procedures for safing an asphalt tanker before
cutting/welding; inadequate supervision of welding operations; absence of
employee hazard training and unsafe work practices.
Employee Is Killed When Tank Explodes While Cutting On It
Blacklidge Emulsions Inc
Employee #1 was cutting on a tank that contained SSI Asphalt
emulsion using acetylene and oxygen. The tank exploded killing him.
Firefighters battle blaze at Monroe asphalt plan in Michigan
September 2014
Firefighters from Frenchtown and Monroe Townships and the City
of Monroe doused a liquid asphalt holding tank that caught fire at the Michigan
Paving & Materials’ plant at the Port of Monroe Tuesday evening that sent
large plumes of black smoke into the air.
The three departments knocked the fire down quickly with both
foam and water after arriving about 5:45 p.m. at the plant off E. Front St.
just west of the DTE Monroe Power Plant.
The plant is the largest liquid asphalt blending facility in
the world, according to Paul LaMarre, director of the port who spotted the
blaze and called 9-1-1. The cause of the blaze was not available.
Metropolitan Engineering, Consulting &
Forensics (MECF)
Providing Competent, Expert
and Objective Investigative Engineering and Consulting Services
P.O. Box 520
Tenafly, NJ 07670-0520
Tel.: (973) 897-8162
Fax: (973) 810-0440
We are happy to announce the launch of our twitter
account. Please make sure to follow us at @MetropForensics or @metroforensics
Metropolitan appreciates
your business.
Feel free to recommend our
services to your friends and colleagues.