Phosphine is a highly toxic gas that forms when aluminum phosphide, a restricted-use
pesticide* typically used in agricultural settings, reacts with water. Acute exposure
can lead to a wide range of respiratory, cardiovascular, and gastrointestinal symptoms,
and can be fatal (
1
). On January 2, 2017, the Texas Department of State Health Services (DSHS) was notified
by the Texas Panhandle Poison Center of an acute phosphine exposure incident in Amarillo,
Texas. DSHS investigated potential occupational phosphine exposures among the 51 on-scene
emergency responders; 40 (78.4%) did not use respiratory protection during response
operations. Fifteen (37.5%) of these 40 responders received medical care for symptoms
or as a precaution after the incident, and seven (17.5%) reported new or worsening
symptoms consistent with phosphine exposure within 24 hours of the incident. Emergency
response organizations should ensure that appropriate personal protective equipment
(PPE) is used during all incidents when an unknown hazardous substance is suspected.
Additional evaluation is needed to identify targeted interventions that increase emergency
responder PPE use during this type of incident.
Investigation and Response
At approximately 5:00 a.m. on January 2, 2017, emergency responders were dispatched
to a single-family residence following a 9-1-1 call reporting shortness of breath,
loss of consciousness, and other symptoms among occupants. These health effects were
initially thought to be the result of carbon monoxide exposure; however, air monitoring
detected no carbon monoxide. Emergency responders discovered that a restricted-use
pesticide containing aluminum phosphide had been applied outside the residence several
days before the 9-1-1 call. It was determined that phosphine had been released when
the pesticide reacted with water, first from ambient humidity, and then when attempts
were made to wash the pesticide away on January 1, 2017.
Because a hazardous substance was suspected, the City of Amarillo dispatched a hazardous
materials (HAZMAT) team composed of fire department personnel and established a secure
perimeter around the home. Persons found inside were assisted out of the residence,
given emergency medical care, and transported to a nearby hospital. Domestic animals
found on-scene were decontaminated by dry brushing and taken to a local animal welfare
facility. The local health authority issued a health alert to inform medical care
providers.
Later on January 2, the City of Amarillo requested a toxicologic consultation from
DSHS related to the incident. Based on incident response activities described during
the consultation, it was determined that emergency responders might have been exposed
to phosphine at the scene. Therefore, DSHS investigated potential occupational phosphine
exposures and associated health effects among all City of Amarillo personnel who participated
in the emergency response.
DSHS reviewed Texas Poison Control Network call records related to the event, and
then designed a standardized health questionnaire based on the Agency for Toxic Substances
and Disease Registry’s (ATSDR’s) Assessment of Chemical Exposures toolkit to interview
potentially exposed emergency responders (
2
). Data collected included demographics, work history, role in the response, PPE use,
potential exposure to phosphine and related acute health effects, emergency response
training, and medical care received. Local health department personnel administered
the questionnaire for DSHS via in-person and telephone interviews from January 23
through February 3, 2017. Data were analyzed by DSHS; data that could potentially
identify an individual were suppressed if counts were fewer than five.
Fifty-one emergency responders participated on-scene in the response. Air monitoring
data were limited, so all were considered potentially exposed to phosphine and contacted
for a follow-up interview. All 51 (100%) responders participated, including fire,
police, animal welfare, and emergency medical services personnel. The median emergency
responder age was 31 years (range = 20–54 years) and the median length of time in
their current job was 5 years (range = 2 months–30 years).
Eleven responders (21.6%), including seven firefighters and HAZMAT team members, reported
use of respiratory protection while on-scene; none of these persons reported symptoms
within 24 hours or sought medical care following the incident (Table 1). Fifteen (37.5%)
of the 40 emergency responders who did not use respiratory protection received medical
care for symptoms or as a precaution after the incident. Seven (17.5%) of these 40
reported new or worsening symptoms within 24 hours of the response. Symptoms included
irritability, ocular pain or burning, headache, nausea, drowsiness, dizziness, burning
of nose or throat, abdominal cramps, diarrhea, generalized weakness, trembling legs
or hands, and trouble walking.
TABLE 1
Characteristics of emergency responders potentially exposed during a phosphine release
event (n = 51) — Amarillo, Texas, 2017
Characteristic
No.* (%)
Role during response operations†
Provide medical care
15 (29.4)
Animal control
9 (17.6)
Rescue victims/First response
9 (17.6)
HAZMAT team
8 (15.7)
Security/Guard perimeter
5 (9.8)
Supervise
5 (9.8)
Operations and logistics
<5 (—)
Other
<5 (—)
Unknown
<5 (—)
Initial information received before on-scene arrival†
Medical emergency
38 (74.5)
Possible carbon monoxide release
11 (21.6)
Unknown chemical hazard
10 (19.6)
HAZMAT
7 (13.7)
Phosphine release
<5 (—)
Other
<5 (—)
Unknown/Missing
<5 (—)
Hours worked at incident site
§
<1
15 (30.0)
1–1.9
17 (34.0)
2–2.9
7 (14.0)
≥3
11 (22.0)
Respiratory protection used
Yes
11 (21.6)
No
40 (78.4)
Symptoms of illness within 24 hours of the incident¶
Yes
7 (13.7)
No or not sure
44 (86.3)
Medical care sought
Yes
15 (29.4)
No
36 (70.6)
Abbreviation: HAZMAT = hazardous materials.
* Counts <5 suppressed to protect confidentiality.
† Categories are not mutually exclusive.
§ n = 50.
¶ Fifteen (37.5%) of the 40 emergency responders who did not use respiratory protection
received medical care for symptoms or as a precaution after the incident. Seven (17.5%)
of these 40 reported new or worsening symptoms within 24 hours of the response. None
of the 11 who used respiratory protection reported symptoms or having received medical
care.
Among the 40 responders who did not use respiratory protection, 14 (35%) provided
the following nonmutually exclusive reasons: did not know it was needed or were not
told to use it (five); rescuing victims was more important (four); did not know the
contaminant was present (four); was not required for the work performed (two); and
did not have equipment (one).
Thirty-seven (72.5%) of the 51 responders stated that their agency had plans or standard
operating procedures for responding to situations where hazardous materials are present.
Forty (78.4%) reported receiving at least one emergency response training
†
before the incident (Table 2), including 29 (72.5%) of the 40 responders who did not
use respiratory protection.
TABLE 2
Emergency response trainings received by responders who were potentially exposed during
a phosphine release event (n = 51) — Amarillo, Texas, 2017
Training
No.* (%)
Any emergency response training†
40 (78.4)
First responder awareness
27 (52.9)
Hazardous materials technicians, 24 hr.
26 (51.0)
First responder operations, 8 hr.
15 (29.4)
Other§
14 (27.5)
HAZWOPER, 24 hr.
5 (9.8)
HAZWOPER, 40 hr.
<5 (—)
No emergency response training¶
11 (21.6)
Abbreviation: HAZWOPER = hazardous waste operations and emergency response.
* Counts <5 suppressed to protect confidentiality.
† Categories are not mutually exclusive.
§ Includes animal control, animal cruelty training (levels 1, 2, 3); National Incident
Management Incident Command System 100, 200, 300, 400, 700 and 800; and police academy
training.
¶ Responders might not have been required to take trainings listed as a condition
of employment.
Discussion
CDC and other agencies have developed protocols and tools to facilitate implementation
of best practices for responding to incidents involving unknown chemical hazards,
and their use has been recommended following similar incidents in the past (
3
,
4
). Federal regulations require the use of appropriate respiratory protection in emergency
responses involving suspected hazardous substances.
§
DSHS recommends implementation of these recommendations and has worked with the National
Institute for Occupational Safety and Health Emergency Preparedness and Response Office
to develop and disseminate educational materials targeted to emergency responders
and emergency response organizations to highlight the importance of using appropriate
respiratory protection.
The 51 emergency responders involved in this incident were faced with limited information
about the hazards present, combined with the need to act quickly to rescue victims.
Many did not use recommended respiratory protection. These issues exemplify challenges
faced by emergency responders who often confront unknown hazards and, given the need
to save lives or secure the scene, might feel they do not have time to identify, obtain,
and don recommended PPE (
3
,
6
). They also might perceive that PPE would physically restrict their ability to perform
required tasks (
6
).
Studies of other incidents involving the known or suspected release of hazardous substances
have similarly found low prevalences of respiratory PPE use among emergency responders,
especially police and emergency medical services. For example, one investigation found
that among 92 emergency personnel who responded to an unintentional vinyl chloride
release, only 20 (21.7%) reported using indicated respiratory protection during the
response (
3
). Multiple studies have found that the prevalence of appropriate respiratory protection
was low among emergency responders to the World Trade Center collapse (
7
). A recent analysis of ATSDR surveillance data found that, among 1,275 emergency
personnel with known PPE status who were injured or became ill during acute hazardous
substance release incident responses during 2002–2012, only 382 (30.0%) wore some
type of respiratory protection (
8
). Respiratory protection prevalence was 45.8% among injured firefighters, compared
with 1.4% among police and 2.3% among emergency medical services personnel. Firefighters’
injuries were more likely to involve trauma or burns than were those sustained by
other types of responders. Because PPE use among emergency personnel who were not
injured or ill was not collected, it was not possible to assess the effectiveness
of PPE in preventing injuries and illness.
The findings in this report are subject to at least two limitations. First, information
bias is possible because exposure and symptom status were identified by self-report.
However, no data were available to estimate individual phosphine exposure. Personal
air monitoring was not conducted, and air samples were not collected inside the residence
before remediation. Second, not all symptomatic persons sought medical treatment,
so medical records were insufficient to assess health outcomes. Therefore, self-report
was the most comprehensive source of information on exposure and health outcomes.
This incident demonstrates that, although important, standard emergency responder
trainings alone might not ensure correct PPE use during this type of incident response.
Studies among health care, farm, construction, and manufacturing workers have found
that individual behavioral interventions (e.g., training and education) alone do not
significantly improve respiratory protection use (
9
). Some studies have found that interventions targeting social and organizational
factors, such as safety climate, do positively impact PPE use (
6
). However, few studies of PPE-related behavioral interventions have been conducted
among emergency responders, so methods for improving compliance with existing PPE
guidance and regulations among responders are not well understood. Additional evaluation
is needed to identify targeted individual and organizational interventions that effectively
increase appropriate PPE use among emergency responders during incidents involving
unknown hazards.
Summary
What is already known on this topic?
To prevent exposure to harmful chemical substances among emergency responders, use
of respiratory and other personal protective equipment (PPE) is recommended during
incident responses when release of an unknown hazardous substance is suspected. Past
studies have found low prevalences of respiratory protection use during hazardous
substance release incidents.
What is added by this report?
Forty (78.4%) of 51 emergency personnel responding to an acute phosphine exposure
incident in Texas in January 2017 did not use respiratory protection, including 15
(37.5%) who received medical care after the incident and seven (17.5%) who reported
new or worsening symptoms consistent with phosphine exposure within 24 hours of the
incident. The majority had received standard emergency response training and knew
of agency standard operating procedures for responding to incidents involving hazardous
substances.
What are the implications for public health practice?
Although emergency responder risk of exposure during incidents involving unknown hazardous
substances is well documented, methods for improving compliance with existing recommendations
and regulations for respiratory protection use are not well understood. Additional
evaluation is needed to identify targeted interventions that effectively increase
appropriate PPE use among emergency responders during incidents involving such unknown
hazards.