Example – Ethylene Dibromide
This month our example is Ethylene
Dibromide, which has a chemical formula of
Dibromide is only slightly soluble in water (0.43% [4.3
grams/liter] at 86 °F) and soluble in most organic
solvents. Ethylene Dibromide is listed under the UN #
(United Nations Number) by the US Department of
Transportation: UN 1605 and has a CAS # of 106-93-4.
Ethylene Dibromide is a nonflammable colorless,
heavy liquid with a sweet chloroform-like odor at room
temperature above 50°F (10°C). Its odor is not
detectable at a low enough concentration to be
considered a warning of excessive exposure. A liquid at
room temperature, ethylene dibromide readily penetrates
skin, cloth, and other protective materials such as
rubber and leather. It is nonflammable. Persons whose
clothing or skin is contaminated with liquid Ethylene
Dibromide (above 50 °F) can secondarily contaminate
others by direct contact or through off gassing vapor.
The liquid is heavier than water. When heated to
decomposition, it may release gases and vapors such as
hydrogen bromide, bromine, and carbon monoxide. Ethylene
Dibromide should be stored in a dry place at ambient
Ethylene Dibromide is produced by liquid-phase
bromination of ethylene at 35‑85°C. This is followed by
neutralization to free acid and purification by
distillation. Ethylene Dibromide was used extensively as
a scavenger for lead in gasoline and as a pesticide and
an ingredient of soil, vegetable, fruit, and grain
fumigant formulations. However, these uses have almost
disappeared in the United States. It is used to some
extent as a chemical intermediate, gauge fluid, and as a
nonflammable solvent for resins, gums, and waxes.
include 1,2-Dibromoethane, Ethylene bromide, Glycol
Standards and Guidelines
8-hour TWA = 20 ppm; acceptable ceiling concentration =
REL-TWA = 0.045 ppm; 15-min ceiling limit = 0.13 ppm
IDLH (immediately dangerous to life or health) = 100 ppm
As shown above, the OSHA and NIOSH TWA values are
substantially different, and this is most likely because
NIOSH has Ethylene Dibromide listed as a carcinogen. The
PEAC-WMD tool will typically display the most
conservative TWA value if the OSHA and NIOSH values are
Incompatible with strong oxidizers, magnesium,
alkali metals, and liquid ammonia.
Exposure Ethylene Dibromide alkylates macromolecules
causing cellular disruption and reduced glutathione
levels. Cellular disruption in tissues and organs, such
as liver and kidneys, results in progressive
dysfunction. Manifestation of some of the effects of
acute high exposure may be delayed a few days. Children
do not always respond to chemicals in the same way that
adults do. Different protocols for managing their care
may be needed.
- Early symptoms of acute exposure include
irritation of the nose and throat. Exposures of moderate
to severe intensity produce respiratory manifestations
ranging from cough, chest pain, and dyspnea to
bronchitis, pneumonitis, pulmonary edema, and
hemorrhage. Pulmonary edema occurred 3 days after oral
poisoning in one fatal human case.
may be more vulnerable because of higher breathing rate
per kg of weight and failure to evacuate an area
promptly when exposed. Hydrocarbon pneumonitis may be a
problem in children.
Ethylene Dibromide is a mild central nervous system
depressant. Drowsiness has been reported following
ingestion and inhalation. Inhalation of vapors in a
confined oxygen-deficient space has caused rapid loss of
consciousness, coma, and death.
- Liquid Ethylene Dibromide is a skin irritant.
Brief skin contact or contact with contaminated clothing
causes erythema and discomfort. Splashing of the liquid
on the skin causes a sensation of cooling because the
liquid evaporates quickly. Prolonged skin contact may
cause blistering and skin ulcers (may be delayed 24–48
hours). Ethylene Dibromide can be absorbed through the
skin to produce systemic effects. Exposure to certain
chemicals can lead to Reactive Airway Dysfunction
Syndrome (RADS), a chemically- or irritant-induced type
of asthma. Because of their larger relatively surface
area:body weight ratio, children are more vulnerable to
toxins absorbed through the skin.
- Conjunctivitis has been reported after exposure to
Ethylene Dibromide. Eye contact with the compound may
cause temporary loss of vision because of destruction of
tissues in the eye.
- Ethylene Dibromide poisoning often affects the
liver. Significant liver damage has resulted from
inhalation and ingestion of Ethylene Dibromide. Necrosis
of the liver was a chief finding in a fatal case of
acute oral poisoning. In two fatal cases of
inhalation/dermal exposure, serum aspartate
aminotransferase and lactic dehydrogenase were elevated
- The kidney is often affected in Ethylene Dibromide
poisoning. Severe renal lesions were reported in fatal
cases of acute oral poisoning and also inhalation
poisoning. Lesions included necrosis of the tubular
epithelium, cytoplasmic vacuolization of the proximal
convoluted tubules, and tubular protein casts.
- Abdominal pain, nausea, vomiting, and diarrhea
have been reported after Ethylene Dibromide ingestion.
Metabolic - Metabolic acidosis
can occur after high exposure to Ethylene Dibromide.
Sequelae - Patients who develop severe acute
neurologic injury but survive may have both central and
peripheral neurologic effects that persist indefinitely.
Exposure No reliable reports exist of adverse health
effects in humans exposed chronically to Ethylene
exposure may be more serious for children because of
their potential for a longer latency period.
- The Department of Health and Human Services (DHHS)
has determined that Ethylene Dibromide can reasonably be
anticipated to be a human carcinogen, based on Ethylene
Dibromide-induced tumors in multiple sites and by
various routes of exposure in animals. Results from
epidemiological studies have been inconclusive.
Reproductive and Developmental
Effects - There is inconclusive but suggestive
evidence that Ethylene Dibromide may reduce fertility in
men. Antispermatogenic effects have been demonstrated in
various animal species. Ethylene Dibromide is included
in Reproductive and Developmental Toxicants, a
1991 report published by the U.S. General Accounting
Office (GAO) that lists 30 chemicals of concern because
of widely acknowledged reproductive and developmental
consideration regarding the exposure of pregnant women
is warranted, since Ethylene Dibromide has been shown to
be a genotoxin; thus, medical counseling is recommended
for pregnant women.
In using the PEAC application we
access information for the chemical by first locating
Ethylene Dibromide in the database. The following
figures show the screens displayed for chemical
properties, Figure 1 for the PEAC-WMD for Windows
application and Figure 2-5 for the PEAC‑WMD for
the Pocket PC application.
Figure 1 - Using the Lookup By:
Name for Ethylene Dibromide using the PEAC-WMD for
Review of the information displayed
in the chemical properties screen whether in Figure 1
(above) or Figures 2-4 (below), show chemical properties
values discussed earlier at the top of this discussion.
As you can see, the published toxicity values, e.g.,
IDLH and the TEELs (Temporary Emergency Exposure Limits)
published by Department of Energy are provided. We will
use the IDLH as the Level of Concern when we develop the
PAD a little later.
Figure 2 – Selecting Ethylene
Dibromide using the PEAC-WMD for Pocket PC
Figure 3 – The top portion of the
Chemical Properties Data Display Screen
Figure 4– The bottom portion of
the Chemical Properties Data Display Screen
The PEAC-WMD application provides
more than just the Chemical Properties for the
identified material, the Chemical Properties are
just the default information screen displayed, by
clicking (if running the Windows version, see Figure 5)
or tapping (if running the Pocket PC version, see Figure
6) on the drop-down box where Chemical Properties
is displayed on the screen, the user is provided with a
list of other databases that provide information for the
selected chemical (Ethylene Dibromide in our current
example). So the search is done once, and the user is
indexed into the different databases easily and quickly.
Figure 5 – Accessing other
databases from the PEAC-WMD for Windows
Figure 6 – Accessing other
databases from the PEAC-WMD for Pocket PC
A quick review or sampling of the
type of information available in each of these screens
is now provided. First is access to Respirators
Recommendations, these are primarily taken from the
NIOSH Pocket Guide and provide the user with different
types of respirators for increasing concentrations. A
sample of the information is provided in Figure 7.
Likewise the Chemical Protective Clothing (CPC)
database can be accessed by clicking on either the
All Chemical Protective Clothing or the
Available Chemical Protective Clothing selection
as shown in Figure 8. The All Chemical Protective
Clothing displays all the CPC entries in the
PEAC‑WMD database for the selected chemical vs. the
Available Chemical Protective Clothing displays
just those CPC entries that match the manufacturers the
user has previously identified as the products the
response organization typically keeps in inventory.
Figure 7 – Respirator
Recommendations for Ethylene Dibromide
Figure 8 – Chemical Protective
Clothing for Ethylene Dibromide
The IC (Incident Commander) will
typically utilize more than a single resource for
developing a response plan but sometimes the information
in other resources will use a different name for the
same substance. Clicking on the Synonyms
selection will provide a quick list of other names
the substance may be referenced by in other resources as
shown in Figure 9. To further assist the responder in
initiating the best response plan, PEAC‑WMD also
provides the generic guidelines found in the ‘orange
pages’ of the DOT Emergency Response Guidebook (ERG).
These are categorized into different types of procedures
depending on the incident and the problem to be
mitigated. An example for Spill or Leak Response
is shown in Figure 10.
|Figure 9 – Synonyms
||Figure 10 – ERG Spill or
Leak Response |
A benefit of using the PEAC tool is
assistance in the development of an evacuation zone for
those chemicals that produce a toxic vapor cloud.
Because of its boiling point Ethylene Dibromide will be
released from a container as a liquid. As with all of
our examples, AristaTek creates a scenario for a spill
or release of the specific chemical, and then we work
through the development of a PAD (Protective Action
Distance) to demonstrate how the PEAC system works.
For our hypothetical scenario using
Ethylene Dibromide as the involved chemical we’ll set
the location to be a manufacturing facility on the North
Side of Miami, FL. There is a fire in a warehouse
adjacent to an outside storage area containing drums of
Ethylene Dibromide. The time is 2:00 AM on July
11th, the temperature is 90°F with clear
skies and very light winds of maybe 2 mph. The drums
have not been breached but the fire is difficult to
extinguish because of the flammable chemicals involved
and there is a concern that the Ethylene Dibromide may
get too hot and BLEVE. There are residential and
commercial areas nearby and light traffic on a nearby
highway downwind. The IC has a monitor positioned to
cool the drums with water, and the question is asked if
there is a reasonable standoff distance that can be
provided with regard to toxic vapor if one or more of
the drums should BLEVE? There are 20+ drums in the
storage area and perhaps 10 are really closest to the
fire and posing a danger.
With a BLEVE there are multiple
concerns, fragmentation of the container that can be
thrown outwards and cause injuries, the possible toxic
vapor clouds that could be formed and possible ignition
of the liquid and vapors when released from the
container. The last concern is not a problem with
Ethylene Dibromide since it is non-combustible. The PEAC
tool does not currently try to predict how far
fragmentation would be a problem. But the PEAC tool can
provide some guidance with regards to toxic vapor clouds
that a BLEVE would release. Our only problem is to
decide how many drums would be involved and would they
all be released at one time.
For this scenario, we’ll assume ten
drums are involved. As seen at the top of the data
display screens, there is a yellow icon displayed; this
is the PEAC icon for notifying the user that a
Protective Action Distance can be calculated. Clicking
or tapping on the PAD icon will display a screen as
shown in Figure 11. Following through the screens, we
provide information on the Meteorology, Container Size,
and Type of Release (Source). As shown in Figure 11, we
have modified the Container Size by increasing the
length of the container by a factor of 10 to give us an
approximate volume for 10 drums if they were all to
BLEVE. If you decide to follow along on this example,
remember to change the location to Miami and the time to
2:00 AM, July 11th.
It’s Miami in July and the
temperature about 90°, light wind is set for 2
mph, clear sky so we’ll set cloud cover to 0%, and
the terrain is Urban/Forest since it’s an urban
We have selected from our list
of container sizes the Drum/Barrel
selection. This provides us with a default
size that should get us pretty close to the actual
size, but for only one drum.
To quickly get the approximate
volume for ten drums, we’ll just increase the
length of the container by a factor of 10 or to a
value of 28.3 feet.
As the scenario calls for,
we’ve selected BLEVE or Pressure Explosion
as the Source type of release.
Figure 11 – Calculating a PAD using the
By pressing the right arrow at the
top of the screen, the PEAC system will display a screen
as shown in Figure 12. This calculates a PAD
(Protective Action Distance) based on the default
Level of Concern the IDLH of 100 ppm. This
evacuation or standoff distance is based on the toxicity
of Ethylene Dibromide, it is not based on what
fragmentation of the containers might occur and be
thrown outward from the storage area.
Figure 12 – Default PAD for Ethylene
Dibromide-Using the IDLH of 100 ppm
Now we can provide the IC with some
guidance as to how far downwind people might be at risk
if the drums were to BELVE.
Portions of this discussion were
adapted from the Agency for Toxic Substances and Disease
Registry (ATSDR) Web site for Medical Management
Guidelines at: http://www.atsdr.cdc.gov/.