National Environmental Health Association: NEHA



Paramedics rushed to a water park in Antioch this afternoon to treat more than 30 children in distress. The Antioch water park is on Lonetree Way, just across the street from Deer Valley High School. ABC’s Ken (Inaudible) is there now, and Ken, it sounds like pool chemicals may be the problem here, right?

Well Frank, there were 34 children that complained of symptoms that you would expect to see from exposure to a chemical such as chlorine, but many questions remain about just how this happened.

There are several pools at the Antioch water park, but only one where children complained of being sick, the shallow pool at the back corner of the park.

Many of the children complained to us of minor respiratory distress, soreness of throat, coughing.

These are images taken just after firefighters arrived along with 18 ambulances. Seventeen of 34 children who said they felt sick were taken to the hospital. The Contra Costa County Hazmat Team inspected the pool chemical storage area to see if that’s where the problem originated.

As far as what we found, we found nothing that would be consistent with the symptoms that were exhibited here at the pool today.

County officials say samples of the pool water did show an elevated level of chlorine above the state standards.

Department of Health has closed the pool because it does not qualify (inaudible) regulatory standards.

Michele DiMaggio with the County’s Environmental Health Department says ten parts per million is the upper limit for (inaudible) swimming pool like this. The water tested at 13 parts per million. That is above the standard but could just three parts per million explain the symptoms experienced by 34 children that caused this Hazmat response?

To this information we have now? No.

DiMaggio says there’s actually a fairly wide gap between the levels of chlorine found in that pool, the elevated levels, and the levels one would expect that would be required to sicken so many children. The County Hazmat team did find compliance issues in the storage area of this facility where pool chemicals are stored, but they say that did not cause this problem so the

So as you can see this incident did get a lot of media coverage, and we were pressed very hard that evening, and throughout the day actually, what the cause of this incident was. And at the time, we really didn’t know. So that resulted in a large investigation on behalf of our agency with Environmental Health to determine what the cause of this incident was and hopefully to prevent it again in the future.

So one of the things that I’d like to go over with everybody is when you get on scene to a call like this, or if you are requested on scene, sometimes it’s difficult to figure out who you should be reporting to, where you fit into the incident command structure. And our structure for this call was we had an Incident Commander, a Safety Officer, and then an Operations Section Chief. And below the Operations Section Chief was the Medical Group Supervisor, which is primarily responsible for treating the victims of this incident. And then they had the Hazardous Materials Group Supervisor which was primarily responsible for assessing the pool and determining if there was an ongoing leak of some sort to cause the symptoms that we saw.

And then we had an Assistant Safety Officer, and we had Environmental Health represented by Michele DiMaggio.

And I’m actually going to turn it over now to Michele, and she will go into their investigation.

Thank you, Matt.

So as mentioned, Contra Costa Environmental Health was notified by our Department’s Incident Response Information System. And this is a department system notification where all departments are notified of a large incident.

A team of five from Environmental Health responded, and we reported to the Incident Commander, which is, you can see on your left-hand slide. This particular pool site is run and inspected by – is run by the City and inspected by Contra Costa Environmental Health. In Contra Costa County, Environmental Health is responsible and regulates all recreational health facilities.

This particular site had five pool sites. The sports pool, splash pool, and tag pool were operated under one equipment system or equipment room. The boulder pool and the lap pool was operated under another equipment room.

They all had separate systems, which turned out well.

The sports pool, as you see on the upper right-hand side, was the incident, and that’s where the children had reported the illnesses.

So in California Code of Regulations, when there is a hazard such as a chemical exposure, the local health regulator, the regulator in our part, Contra Costa Environmental Health, can use what we call Title 22, and specifically this Code was 65545, to close a pool. At the time of the incident we did have three pools that were out of compliance. In 2015 a new California Code passed where now the maximum chlorine level is to be no higher than ten parts per million. And when we measured the pool, the sports pool in this particular case, we measured it in three different areas. And all areas were above ten. One area was 11, another was at 13.5. So the highest level was at 13.5.

The other two pools that you saw earlier were also either a high chlorine or low pH. We recorded the pH about 6.8.

Due to the hazard of the whole situation, all five pools were closed. And the City also had previously when they evacuated the site.

Here is a schematic of the pool, and if you look at the schematic, and follow the arrows. And this is where the pool level – this is where the water comes in. And then the pump brings in the water, and if you follow the whole system here, you can see the filtration system, and this is – where the arrow is now – is where water can be sampled. It goes in, and the two pumps that were available here were the peristaltic pump for the bleach and the peristaltic pump for the acid. And muriatic acid was used in this particular case. And then the water returns to the pool.

These are the photos from the pool. From the pump room, specifically the sports pool. This was the controller at the particular time.

And (inaudible) measured the sports pool. The pH, again, was at 6.8 or so. However, when I looked at the chemical control unit itself, it was about 7.4, so there was an inconsistency just to start off.

This is the chemical injection points, and these are the pipes that run the chemicals through. Here is the acid pump, and here is the bleach pump.

So at the time of the investigation, we had asked for multiple documents. In the California Code, there are documents that are required. In this particular case, this is the Chemical Controller reading documents. Not necessarily required in the Code, but in this particular case we asked them to print this out. That day, on the 18th, these documents were not available. However, on the 19th when we returned we did receive these documents. Also on the 19th, we opened four out of the five pools. Sports pool, again, due to the inconsistencies, we again measured the pH at about 6.8; however, the Chemical Controller read 7.4. And due to the inconsistency, I maintained the sports pool closed for further investigation.

We also ordered all five pools to be submitted to our Plan of (inaudible) Process just to verify that the specifications on the manufacturers have been completed properly.

And as you see here, we received these, and we collaborated with Hazardous Materials to run over all the documents, which Matt will run through with you now.

Okay, thank you, Michele.

So as Michele mentioned, we received a lot of documents and a lot of data that needed to be analyzed to hopefully determine with some confidence what the cause of this incident was. So what I have presented here on the screen right now is the pool chemical graph data that we analyzed in relation to this incident, and specifically the pool that was affected during this incident.

So what you will see here is there are three lines on this graph. The first is a green line, and that represents the pool pump flow rate, so that is the pool water being pumped through the system in gallons per minute.

The red line shows bleach feed time, so that’s when the bleach is being fed into the pool.

And the blue line represents when muriatic acid, or hydrochloric acid, is being pumped into the pool.

So looking at the data here, you can see that the green line is usually high, meaning that the pool pump is on. It does go off at night, and you see that here on June 16, 2015 at around 10:45 at night the pump goes off, and that’s for backwashing operations that take place to clean sand filters. And then later on the pump comes back on. It’s important to note here in this void where the pool pump is not on that generally chemicals are not introduced into the system during this time, and that’s primarily a result of an interlock system that exists to prevent pool chemicals being injected into the pool system while the main circulation pump is not on.

And then you’ll see later on, once the backwashing activity is done, the pool pump comes back on.

The day in question here is the night of June 17, 2015, and we see, as we would expect, the pool circulation pump goes off around 10:40 at night, as it usually did, to backwash the sand filters. And for unknown reasons the pump does not come back on at 4:40 in the morning or thereabouts as it usually does, as we see that happening the day before. Instead we see the pool circulation system stay off for a period of time until approximately the time of the incident.

During this time the main circulation pump is off, we see that bleach has fed into the system for a period of time. And it’s around 55 minutes or so that that bleach pump is on, as you can see by this spike here that I’m pointing at. So what that represents is the main circulation pump during this time is not on, and bleach is constantly being fed into the circulation system. Just bleach.

And what we determined afterwards during this investigation is that the system actually noticed that I fed 55 minutes of bleach into the system, however the oxidation reduction potential has not gone up, meaning that I’ve introduced quite a bit of bleach in to the system and I haven’t had a change in the chlorine levels. So there is a lockout mechanism that goes into place for this very reason. And it takes a manual override at some point to continue introducing chemical into the system when you’ve had it on for this long and you haven’t received the change in oxidation reduction potential that you would anticipate.

For unknown reasons, and during our investigation we were unable to determine who exactly did this, but there was – someone came into the pump room, noticed that the system was in a lockout situation because it had introduced the chemical and didn’t get the change it expected, and there was a manual safety system override of the controller at that time. That override resulted in the system then introducing bleach for a period of approximately 22 to 23 minutes. It goes off. It comes on and introduces about 57, 58, 59 minutes more of bleach. Does the same thing. Comes back on. And then you’ll see, also during this time, muriatic acid is introduced to the system. And you see it for about five minutes here and about 34, 35 minutes here.

And so what’s going on is you have the dry pipe where the pool water is not being circulated, and you have two different chemicals being introduced to that pipe and not being sent to the pool for dilution to do its normal activity.

At approximately 1429 hours, or thereabouts, someone notices at the pool room that the main circulation pump is not on. And that pump all of a sudden comes on, presumably by an employee taking action to turn it on. And we see the huge spike as we would anticipate, then the pool circulation pump comes back on. And within seconds we get our first 911 phone call related to this incident or the beginning of this incident.

So, that is the graphical representation of the data that we received from the pool water operator. Graphically represented in a different way, which may be easier for some folks, is in this method where when the pool water pump is on. It goes off at approximately 10:40 at night, and it doesn’t come on until approximately 2:29 the next day. During that time we had bleach introduced for periods of time, represented by the yellow arrow, and we have acid introduced into the line represented by the red arrow. And there is a safety system override that’s manually done which allows more chemical to be introduced into the system. And then shortly after the pool water pump comes on, we have our first call to 911 reporting symptoms similar to a chlorine exposure.

So going back to the representation of the pool water system and the chemical system that Michele presented earlier, essentially what we have is we have the primary circulation – or the only circulation – pump for the pool water off for approximately 16 hours. And during this time bleach and muriatic acid are pumped into the system, and those were on intermittently throughout those 16 hours. And for unknown reasons, the flow meter, which is supposed to be an interlock mechanism with the chemical controller, doesn’t do its job and does not lock out the system from introducing chemicals into the pipe.

So the resulting chemical reaction, without getting too far back to our chemistry days, is we had an acid, muriatic acid in this case, or hydrochloric acid, being mixed with bleach, sodium hydrochloride, and that liberates, after a few chemical reactions, chlorine gas. And chlorine gas, the physical properties of that gas, are that it’s not really readily absorbable in water, so water – it does not go into solution in water. And it’s heavier than normal air. So what we presume happened is when somebody – going back to our representation earlier here – when somebody turns on the pool water circulation pump here, there is a bolus of chemicals that is sent to the pool, and through the pool system, chlorine gas bubbles up through the water. It is not very readily absorbed by water. And as a result, we have chlorine gas that surfaces, and that chlorine gas primarily sits on the surface of the water until wind blows it away, where kids’ heads are probably bobbing and having a great time. So that resulted in many exposures to what we presume to be chlorine gas.

I’ll now turn it back over to Michele DiMaggio to go into the corrective actions that our agency took.

So during this time, we’re not only doing a site evaluation and site investigation, but we’re also asking for multiple documents, again that were provided intermittently. Not only the chemical controller sheets, log in sheets, but also the daily activity sheets and any other records. Employee illness sheets, anything related to the pool itself.

We also used the CDC employee investigation form just to ask questions about employees and how they were feeling, and what they observed and what they overheard. So we spent some time talking to employees and the maintenance worker at that time.

As part of the process and enforcement action, we asked the management to come into our office, and we conducted what is called an Administrative Hearing basically to discuss the situation and how to resolve some issues that had moved forward.

Also during this time this particular site had submitted their plans through our plan review process for review and compared the manufacturer specification sheets to the actual equipment on site, and it turned out that there were some pieces of equipment that needed to be replaced.

Also we connected our county’s Emergency Planner with this particular site operator to create the emergency plan which you see here on top.

So our County Emergency Planner assisted with creating an emergency action plan, and this action plan was, if another incident occurred, what they had in place to respond to this. I do have to say that the employees on site, the lifeguards did a wonderful job in evacuation and communication to each other, and we also found that they communicated very well with our emergency responders.

Also a part of the plan was creating documents for future to verify who is doing what. In this particular case the lifeguards were not only responsible for observations but they were also responsible for the sample in the morning. There were also employees that took samples and looked at the equipment, chemical controller and others in the maintenance equipment room, so we had a pool chemical log for the lifeguard and we had a pool chemical log for the employees, which is here.

We also asked them to monitor more closely their chemical controller. Who is looking at the chemical controller? Are the probes being cleaned according to manufacturer specifications? One of the items that we saw that we were thinking about, were the probes dry at this particular time? Who was monitoring that?

And also we asked them to monitor for who was going in and out of that equipment room. So this was also a hazardous materials site inspection, so we wanted to make sure that they had who was going in and who was going out.

We also asked them to maintain the incident itself. What happened that day, and who was involved.

So lessons learned. Hazmat goes underreported. There is a lack of awareness from the pool operators. The pool operators are not sure what to do when these particular situations.

Lack of experience, especially with our Environmental Health, and are we trained to respond to emergency situations, especially if we’re not connected with their hazardous materials.

Communications. If Environmental Health is not part of the hazardous materials, how do we know when a pool has a chemical incident?

And especially on 911 calls, to make sure that Hazardous Materials and Environmental Health are notified when it’s a regulated site. This pool was a regulated site, regulated by Environmental Health.

So what’s next specifically for our division, Environmental Health?

We are creating a Health Officer Advisory. These particular situations. We’re also creating a letter to manufacturers requesting more information about the chemical controllers and asking them what type of system is in place when incidences occur.

We’re lobbying for change, especially for certification of the chemical controllers. And we’re asking for secondary site specific engineering controls. What can be put in place to basically stop any chemicals being released when the pump is off.

As part of our outreach, our lead Recreational Health person has created many documents, including, you know, those basically handouts of public pool safety. Every year we give about two to three months of training to our local pool operators, and basically what our regulations are, what Environmental Health looks for, and we’re there to answer any questions. And we do make ourselves available to provide onsite training.

This includes response to emergency situations, so our Division and our Lead created emergency situations to public pools. So that not only includes chemical exposures, but, for example, if there’s flooding, or if a pool site is empty, and mosquitoes, such as that.

We maintain our website, try to provide as much information as possible.

And we have multiple, multiple handouts that are provided by our inspectors, including when there is ill employees.

So now what we’ll change to, Jason Wilken will discuss the statewide picture.

Okay, thank you. My name is Jason Wilken. I am a CDC field assignee to the state of California for emergency preparedness and response. And Matt and Michele just gave a very detailed presentation on their investigation of the June 18th chlorine release at a water park in Antioch.

And their presentation has numerous valuable lessons regarding the role of first responders and Hazmat and Environmental Health investigators following a mass casualty chemical incident, and I hope that you’ll be able to take some of that training back to your agency.

And I’d like to conclude our presentation today by placing the Antioch investigation in a statewide context.

So 17 days before the release at the Antioch pool, a similar incident took place. It was a clear, warm June 1st, and a group of third graders on a field trip were swimming in a recreational swimming pool in the city of Redding, California. And according to bystanders, while the children were playing in the pool, a large bubble was suddenly emitted releasing a cloud of yellowish gas.

Now children are, of course, curious by nature, and they swam towards the yellow gas. One child, a nine-year-old girl, experienced nausea, vomiting, difficulty breathing, and chest pain, and she was taken to a nearby emergency department, and it was there that here behavior became confused, she had a rapid heartbeat and even more difficulty breathing. And she had to be intubated to protect her airway and was taken by air ambulance to a hospital with pediatric ICU. And overnight her breathing improved. She was extubated the next day, given oral steroids and albuterol. Her breathing further improved, and she was discharged the following day.

Now another child from that same incident, a nine-year-old boy, was also taken to the emergency department with rapid heartbeat and breathing and low blood oxygen saturation. His care was managed with steroids and albuterol. Fortunately he did not have to be intubated. His breathing improved overnight. He was discharged the next day.

So these two children were the most severely affected by that incident, but they were certainly not the only ones impacted because in all 28 children were sickened by the chlorine release at the Redding swimming pool. One child was released on the scene. The other 27 were transported to local emergency departments for evaluation. Six were transported by ambulance and 21 were transported by the school bus that took the children on their field trip to the swimming pool with EMS personnel on board the bus.

Now there are some similarities between these two incidents. In both cases the chemical pump continued to deliver muriatic acid and (inaudible) hydrochloride when the main recirculation pump was off. When the main recirculation pump was turned back on, a bolus of pool chemicals was released resulting in a secondary release of chlorine gas. And in both cases the main recirculation pump was turned back on when there were bathers in the pool, all of them children.

Here’s another example. In October 2015, in the city of Danville, also in Contra Costa County, a power outage caused a shutdown of the pool recirculation pump. And now at this point the chemical controller should have restricted the pool chemical feeder, but there was a malfunction in the chemical controller’s flow sensor, and that caused a dangerous buildup in the recirculation line. When a maintenance worker restored power to the recirculation pump, similar to what was observed in the Antioch and Redding incidents, a bolus of chlorine gas was released into the pool. Now this incident took place at a high school pool where members of a water polo team were practicing.

Now EMS was not activated as a result of this incident so we don’t know how many people were sickened, but we do know that at least six received medical attention at an emergency department or with their primary medical provider. And among these patients was a 14-year-old girl that was taken to an emergency department where she displayed rapid breathing with low blood oxygen saturation. And she was given albuterol and steroids and admitted to the pediatric floor. Her breathing improved with treatment, and she was discharged from the hospital on the third day.

Now also in October, this time in the city of Santee in San Diego County, this was a very different incident but also quite revealing in terms of pool chemical safety. Students and teachers at an elementary school began complaining of nausea, shortness of breath, and eye irritation around 8:30 in the morning, and persons at the school described a caustic odor.

Seventy-seven students and four staff were transported by emergency department for an evaluation. This elementary school is about 1,000 feet from a nearby YMCA. And the chemical pump at the YMCA had failed overnight releasing about 300 gallons of sodium hydrochloride. And the spilled sodium hydrochloride solution overflowed from a secondary containment basin into the storm drain.

A worker noticed the spill in the morning and tried to treat the spill with sodium thiosulfate, which created a vapor which impacted these 81 persons at the nearby elementary school. Fortunately all the students and staff were released with minor injuries.

Fortunately no one died as a result of these four incidents. However, the chlorine exposures and impacts were substantial. In all, 154 persons, mostly children, were impacted by these chlorine releases at recreational swimming pools in California in 2015. And four were so seriously injured as to require hospitalization.

So consider the presentation on the Antioch incident and also these other mass exposure, and potential mass casualty, incidents at recreational swimming pools last year. Now obviously Hazmat has a major role to play in response to this sort of incident. Michele thoroughly detailed the role of county Environmental Health in response to a mass chemical exposure. And as Matt had detailed, there is no uniform standard in the organizational relationship between Hazmat and Environmental Health. In each county in California it’s different.

So today we saw an excellent example of how these two can work together, and I’d ask you to consider what is your relationship with your Hazmat agency? Are you organized together in the same department? Do you meet regularly? Do you have joint exercises? Or do you even have contacts with your Hazmat agency?

Events described in this presentation might also fall under the domain of county Public Health. Public Health’s organizational framework also varies by county. Sometimes county Environmental Health and Public Health are within the same agency. Sometimes they’re completely separate. If you had a similar incident, does county Public Health get involved?

Public Health obviously has a stake in preventing injury and illness. Does your agency have a working relationship with county Public Health?

And these three agencies provide complementary methods and legal mandates and authorities for preventing and mitigating chemical exposures with regulatory response and surveillance functions.

In the case of California Department of Public Health’s Emergency Preparedness Team, we interface with each of these functions at the state level.

To move back to the Antioch water park incident, we illustrated how these different disciplines fit together. Contra Costa County Hazmat reported compliance issues related to the facility’s hazardous materials business plan and noticed that the facility used an underground, unpermitted storage tank.

To address the recirculation system failures, Environmental Health required the facility to operate per manufacturer specifications and to address the possibility of human error. The facility will have to implement new procedures, policies and trainings.

And our Emergency Preparedness Team has compiled a comprehensive set of health effects data resulting from this and other incidents. And our ultimate goal is to produce and distribute relevant materials to all disciplines that might be involved in such an event.

And I’d like to close by reminding the audience of the Council for the Model Aquatic Health Code, and I believe we have representatives from CMAHC in the audience. Now there’s no federal regulatory agency responsible for aquatic facilities, and standards and regulations vary by state and local jurisdictions.

The CMAHC is a collaborative group involving input from industry and Environmental and Public Health, including the CDC, to manage risk of injury and illness in aquatic settings. And the MAHC includes comprehensive best practices and accompanying scientific rationale to inform design and updating of local and state regulations.

Now the MAHC solicits comments for updates every two years. Next year is one of the update years, and we will be presenting potential updates to the MAHC based on our findings here. If you’re not already a member, I recommend that you join, and we look forward to hearing your input later next year.

And with that I will close our presentation. I’d like to thank Svetlana, Matt, and Michele for presenting with me today, and thank you very much for attending.

Thank you Jason, Michele, Matt, and Svetlana, and thank you everyone for attending today’s webinar: Opportunities for Preventing Mass Chlorine Exposures at Recreational Swimming Pools. On behalf of the National Environmental Health Association and our presenters, thank you for joining us today, and have a great rest of your day.

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