To ensure a safe drinking water supply, water utilities use large amounts of hazardous chemicals to maintain water quality and protect against the transmission of pathogens. Data about releases of these chemicals used by water utilities is limited. This presentation analyzes chemical release data from 17 states that reported to the Agency for Toxic Substances and Disease Registry's chemical event surveillance system and identified over 482 release incidents from 2000-2009 attributed to water utilities.

1. Chemical Releases
in the Water Industry
Steven Ross, CHMM, CEM, CFPS
Environmental Health and Safety Analyst
Las Vegas Valley Water District

2. Introduction
 Various chemicals are used to maintain water
quality and protect against the transmission of
pathogens.
 However, sometimes these chemicals are released
causing employee injuries, equipment damage,
and impacts to the public.
 This presentation summarizes the releases of
water treatment chemicals and their associated
causes from 2000 through 2009.

3. Goals
 Evaluate chemical release data reported to the
Hazardous Substances Emergency Events
Surveillance (HSEES) System.
 Identify the number and type of chemical releases
associated with water and wastewater facilities.
 Identify the primary contributing factors for each
event.
 Identify any injuries associated with each event.

4. The HSEES System
 From 1990 to 2009, the HSEES system collected data
related to releases of toxic substances from multiple
industry sectors, including transportation.
 Established by the Agency for Toxic Substances and
Disease Registry (ASTDR), a division of the CDC.
 ATSDR funded HSEES systems in 17 states.
 In 2010, the HSEES was replaced by the National Toxic
Substance Events Program (NTSEP).

5. HSEES Participating States
UT
OR
MO
MN
IA
WA
CO
TX
LA
MS AL
FL
NC
WI NY
NJ
MI

6. HSEES Information Sources
 Data collected included general information on the
event, substances released, victims, injuries, and
evacuations from:
 State Environmental Protection Agencies
 City and County Agencies
 Emergency Responders (Police, Fire, EMS)
 Poison Control Centers
 Hospitals
 Local Media
 Federal Databases (DOT, US Coast Guard)

7. HSEES Events
 Uncontrolled or illegal, acute release of any
hazardous substance (except petroleum), in any
amount of a substance listed on the HSEES
Mandatory Reporting List, or
 Any release of a hazardous material in amounts
greater than or equal to 1 gal or 10 lbs.
 Threatened releases of qualifying amounts will be
included if the threat led to an action, e.g.,
evacuation to protect public health.

8. HSEES Data Limitations
 Assumed not all water treatment chemical events
were reported to the HSEES system.
 Some chemicals might have been misidentified or
reported incorrectly to the HSEES system.
(i.e., sodium hypochlorite reported as chlorine).
 Not all 17 states participated during
1990-2009.

9. CHEMICAL RELEASE
EVENTS

10. Methodology
 HSEES system search method:
HSEES Industry Categories (Water Supply).
NAICS Code (221310)
 Identified common water treatment
chemicals released between 2000-2009.
 Cross-referenced event records to confirm
that a water utility or treatment facility was
involved.

11. Water Treatment Chemical Events
 From 2000-2009, approximately 82,796 chemical
events were reported to the HSEES system from
the 17 states.
 Identified 482 water treatment chemical release
events.
 Water treatment chemical events comprised
approximately 0.6% of the total events reported.

12. Frequency of Events per State
11
19
27
35
15
15
32
89
31
9 7
63
32
25 132
33
11
Total events (2000-2009) = 482
>100
75-100
50-75
25-50
0-25

13. Water Treatment Chemicals
 Disinfectants:
 Chlorine
 Chlorine Dioxide
 Calcium Hypochlorite
 Sodium Hypochlorite
 Coagulants:
 Aluminum Sulfate
 Ferric Chloride
 Ferric Sulfate
 Cationic Polymer
 Ammonia:
 Anhydrous Ammonia
 Aqueous Ammonia
 Fluorides:
 Fluorosilicic Acid
 HydrofluosilicicAcid
 Other:
 Potassium Permanganate
 Sodium Hydroxide
 Zinc Orthophosphate
For purposes of analysis, the water treatment chemicals are
grouped into the following chemical categories.

14. Frequency of Chemical Events
Treatment Chemicals No.
Disinfectants 362
Coagulants 47
Other 43
Fluorides 16
Ammonia 14
Total events (2000-2009) = 482
Fluorides
3%
Other
9%
Ammonia
3%
Coagulants
10%
Disinfectants
75%

15. Disinfectants
Total disinfectant events (2000-2009) = 362
Calcium Hypochlorite
0.3%
Chlorine Dioxide
0.3%
Chlorine
65%
Sodium
Hypochlorite
35%
Disinfectants No.
Chlorine 234
Sodium Hypochlorite 126
Calcium Hypochlorite 1
Chlorine Dioxide 1

16. Coagulants
Coagulants No.
Ferric Chloride 17
Ferric Sulfate 16
Aluminum Sulfate 8
Cationic Polymer 6
Total coagulant events (2000-2009) = 47
Aluminum Sulfate
17%Cationic Polymer
13%
Ferric
Sulfate
34%
Ferric
Chloride
36%

17. Other Chemicals
Other Chemicals No.
Sodium Hydroxide 32
Potassium Permanganate 10
Zinc Orthophosphate 1
Zinc Orthophosphate
2%
Potassium Permanganate
23%
Total events (2000-2009) = 43
Sodium
Hydroxide
74%

18. Remaining Chemicals
Ammonia No.
Anhydrous Ammonia 8
Aqueous Ammonia 6
Total ammonia events (2000-2009) = 14
Aqueous
Ammonia
43% Anhydrous
Ammonia
57%
Fluorides No.
Fluorosilicic Acid 12
Hydofluorosilicic Acid 4
Total fluoride events (2000-2009) = 16
Fluorosilicic
Acid
75%
Hydrofluorosilicic Acid
25%

19. EQUIPMENT FAILURE AND
ASSOCIATED ACTIVITIES

20. Equipment/Activities
Equipment/Activities
No. of
Events
Above Ground Tank 203
Piping 169
Ancillary Equipment 63
Other 17
Material Handling 13
Onsite Transportation 8
Waste Disposal Area 7
Underground Tank 2
Above
Ground Tank
42%
Piping
35%
Ancillary
Equipment
13%
Other 4%
Material Handling
3%
Transportation
2%
Waste Disposal
1%
Underground
Tank
0.4%
Total events (2000-2009) = 482
The category of “other” includes a combination of categories.

21. Above Ground Tanks
Treatment Chemicals No.
Disinfectants 168
Other 13
Coagulants 10
Fluoride 7
Ammonia 4
Total tank events (2000-2009) = 203
Disinfectants
84%
Other 7%
Coagulants
4%
Fluoride
3%
Ammonia
2%

22. Piping
Treatment Chemicals No.
Disinfectants 126
Coagulants 20
Other 14
Ammonia 5
Fluoride 4
Total piping events (2000-2009) = 169
Other 8%
Coagulants
12%
Fluoride
3%
Ammonia
2%
Disinfectants
75%

23. Ancillary Equipment
Treatment Chemicals No.
Disinfectants 40
Other 10
Coagulants 8
Ammonia 4
Fluoride 1
Total equipment events (2000-2009) = 63
Other
16%
Coagulants
13%
Fluoride
2%
Ammonia
6%
Disinfectants
64%

24. Material Handling
On-site Transportation
Treatment Chemicals No.
Ammonia 4
Disinfectants 3
Coagulants 3
Other 2
Fluoride 1
Treatment Chemicals No.
Disinfectants 5
Coagulants 2
Fluoride 1
Ammonia
31%
Disinfectants
23%
Coagulants
23%
Other 15%
Fluoride
8%
Disinfectants
63%
Coagulants
25%
Fluoride
13%
Total transportation events (2000-2009) = 8
Total handling events (2000-2009) = 13

25. PRIMARY CONTRIBUTING
FACTORS

26. Primary Contributing Factors
Contributing Factors No.
Equipment Failure 356
Human Error 104
Intentional/Illegal 8
Unreported/Unknown 8
Severe Weather 6
Human Error
21%
Intentional/Illegal
2%
Unreported/
Unknown
2%
Severe Weather
1%
Equipment
Failure
74%
Total events (2000-2009) = 482

27. Equipment Failure
 In the HSEES system, the majority of causes for
equipment failure were reported as “Unknown”
(87%).
 The remaining 13% of reported equipment failures
were caused by:
 Process upsets
 Misapplications
 Overfilling
 Explosions
 Fires, etc.

28. Human Error
Human Error
No. of
Events
Unreported/Unknown 41
Equipment Failure 21
Improper Filling 19
During Maintenance 9
Improper Disposal 6
Improper Mixing 3
Startup/Shutdown 2
Forklift Puncture 1
Process Upset 1
Other 1
Human error events (2000-2009) = 104
Unreported/
Unknown
39%
Equipment
Failure
20%
During
Maintenance
18%
Improper
Disposal
6%
Improper Mixing
3%
Startup/
Shutdown
2%
Forklift Puncture
1%
Other
1%
Process Upset
1%
Unreported/
Unknown
39%
Equipment
Failure
20%
Improper
Filling
18%

29. INJURIES

30. Injuries
 During 2000-2009, 147 persons were injured in water
treatment chemical events, with no reported deaths.
 The population groups most often injured were employees
(86%), general public (12%) and emergency responders
(2%).
 The most frequently reported injuries/symptoms were
respiratory irritation (52%) and eye irritation (32%).
 Of events with persons injured, 73% involved only one
person and the remainder involved two or more people.

31. Injuries by Chemical
Treatment Chemicals
No. of
Events
No. of
Injuries
Chlorine 68 112
Sodium Hypochlorite 5 10
Sodium Hydroxide 6 12
Chlorine Dioxide 1 6
Anhydrous Ammonia 1 2
Aqueous Ammonia 2 2
Ferric Sulfate 1 2
Aluminum Sulfate 1 1
Total number events w/ injuries (2000-2009) = 85
Aqueous
Ammonia
1%
Anhydrous
Ammonia
1%
Aluminum
Sulfate
0.7%
Sodium
Hypochlorite
7%
Sodium
Hydroxide
8%
Ferric
Sulfate
1%
Chlorine
Dioxide
4%
Chlorine
76%
Some of those injured may have had more than one injury (for example,
respiratory irritation and eye irritation.)

32. Primary Contributing Factors for
Events with Injuries
Contributing Factors
No. of
Events
No. of
Injuries
Equipment Failure 47 84
Human Error 33 55
Intentional/Illegal 2 3
Unknown 2 3
Weather 1 3
Intentional/Illegal
2%
Unknown
2%
Weather
1%
Human
Error
39%
Equipment
Failure
55%
Total number events w/ injuries (2000-2009) = 85

33. CASE REPORTS

34. Case Report #1
August 8, 2000
City of Coos Bay, Oregon
Coos Bay/North Bend Water Treatment Facility
The event occurred during the transfer of hydrofluosilicic acid into a day-
tank. Due to problems with the automated pumping system, the transfer
pumps were operated manually. The pumps were inadvertently left on
causing an overflow of the day-tank.
Ultimately 400 gallons of hydrofluosilicic acid flowed into the storm drain
system which caused approximately 2.5 million gallons of fluoride
contaminated storm water to enter nearby Coos Bay, Oregon.
No injuries were reported as a result of the release.

35. Case Report #2
May 2, 2003
St. Louis, Missouri
Missouri American Water Company
The event occurred when a water operator was attempting to hook up a
one ton container of chlorine. Approximately 1,800 pounds of chlorine
was released into the atmosphere. The cause of the release was
determined to be operator error that occurred during the connection
process.
Two employees were treated for minor injuries on-site, but were not
hospitalized. There were no off-site injuries or property damage, however
there was significant damage to the chlorine room resulting in $60,000.00
of repair costs.

36. Case Report #3
June 5, 2007
City of Binghamton, New York
Binghamton Water Treatment Plant
The event occurred when a delivery driver supplying hydrofluosilicic acid
to the treatment plant mistakenly off-loaded hydrofluosilicic acid into a
sodium hypochlorite tank. The resulting reaction caused a large release of
chlorine gas.
The gas was largely contained within sodium hypochlorite storage
building. The roads and one bridge in the vicinity of the treatment plant
were shut down, but residents in the area were not evacuated. The local
Fire Department’s hazmat unit responded and used a water spray to
suppress the chlorine gas.
No injuries were reported as a result of the release.

37. SUMMARY & CONCLUSIONS

38. Summary
 Overall, the findings regarding the types water treatment
chemicals released and the cause of these releases are
consistent with the water industry.
 Out of 482 events, disinfection chemicals, such as chlorine
(49%) and sodium hypochlorite (26%), were the most
commonly released water treatment chemicals.
 These events resulted in the majority of releases to occur
from above ground tanks (42%) and piping (35%).

39. Summary (Cont.)
 A review of the findings also indicates that many events could
have been avoided.
 The most common cause of events occurred due to equipment
failure (54%) and human error (41%), which also resulted in
the majority of injuries (94%).
 Although many causes of equipment failure were reported as
unknown in the HSEES system, the majority of reported causes
resulted in process upsets and system breakdowns.
 The majority of human error caused events (58%) resulted in
the malfunction of equipment and/or the improper filling,
mixing, or disposal of a chemical.

40. Conclusion
 Inspect tanks, containment areas, and areas where
leaks are more likely to occur.
 Ensure equipment is properly maintained and in
good condition.
 Educate employees on safe chemical handling and
storage practices.

41. Conclusion
 Educate chemical suppliers and transporters on
proper delivery procedures.
 Participate in emergency response drills and train
employees on emergency response actions.
 Evaluate how a spill or leak can potentially escape
from your facility.

42. Looking Forward
 Using HSEES data can help to identify targeted
training for employees and emergency
responders.
 Using HSEES data to identify evacuation criteria
and associated injuries to the public or emergency
responders.
 Further research using the new National Toxic
Substance Events Program (NTSEP).

43. Sources
 ATSDR HSEES Web site: http://www.atsdr.cdc.gov/HS/HSEES/.
 Hughes N, Stanbury M., “Hazardous Substances Emergency Events Surveillance
in Michigan”, Michigan Department of Community Health, 2009.
 Henry A. Anderson, MD, “Hazardous Substances Emergency Events
Surveillance (HSEES), Data to Assist NIEHS Training Initiatives”, Wisconsin
Department of Public Health, 2009.
 Stephen C. Gleason, D.O., “Iowa HSEES, Hazardous Substance Emergency
Events Surveillance, Cumulative Report 1993-1997, Iowa Department of
Public Health, 2001.
 National American Industry Classification System, 2007. Bureau of the Census,
United States, Washington, DC, 2007.

44. QUESTIONS?
Steven Ross, CHMM, CEM, CFPS
Environmental Health and Safety Analyst
Las Vegas Valley Water District
steven.ross@lvvwd.com