Pool Safety

Download PDFBy ThinkReliability Staff

Many of the examples of Cause Maps are investigations of an incident that has already taken place.  However, cause maps are also very useful as a proactive, preventative tool.  A thorough root cause analysis built as a Cause Map can capture all of the potential causes of concern in a simple, intuitive format that fits on one page.  Let’s say you have decided to get a pool for your household.  A Cause Map can help you identify the potential hazards of pool ownership, provide solutions for them when possible, and ensure that your pool experience is as safe as possible.

Preventing pool injuries is extremely important.  About 43,000 people each year are injured in and around swimming pools and 600 people drown.  Of the 600, approximately 260 are children under the age of 5.  Half of pool drownings occur in the yards of single-family homes.  Obviously, drowning is a concern when discussing pool safety, but the other top causes of injuries around pools are head injuries, slipping, and electrocution.  Some solutions to these problems are listed below, and are based on causes derived from the Cause Map. (To see the Cause Map, click on “Download PDF” above.)


1) Control access to the pool by using a self-latching, self-locking fence that is at least 4′ tall, that can’t be climbed.  Ensure the doors open outward from the pool and have a latch out of children’s reach.   Use a safety cover when the pool is not in use.
2) Employ drain safety devices such as pumps that shut off automatically when the pipes are obstructed.
3) Keep children within arm’s reach when near a pool.  Don’t put in a pool for your family until your children are at least 5.
4) Keep lifesaving equipment near the pool, including a hook and an approved life-saving flotation device.
5) Don’t drink & swim, and don’t let those who have consumed alcohol near the pool.
6) Take your whole family to swimming lessons.
7) Never swim alone.  Don’t let anybody else swim alone.
8) Use a pool alarm that senses water motion to determine if someone has entered the pool.  Make sure it is always turned on when the pool is not in use.
9) If a child is missing, look first in the pool (most children who drown are found after 10 minutes).
10) Keep a telephone, and emergency numbers, near the pool at all times.
11) Check the water depth before diving, or don’t allow diving in your pool.
12) Learn CPR.  Take your whole family (when they’re old enough) to CPR lessons, too.
13) Don’t allow running near the pool.
14) Use an absorbent material to surround the pool.
15) Use rough material around the pool (such as cement instead of tile).
16) Stay out of the pool during rain or lightning storms.
17) Keep electrical appliances away from the pool (they can cause electrocution even if they are not turned on).

Emergency Landing of American Airlines Flight 268

Downlaod PDFBy ThinkReliability Staff

On September 22, 2008 American Airlines Flight 268 en-route from Seattle to JFK Airport made an emergency landing at Chicago’s O’Hare Airport.  Nobody was injured, although the landing gear sustained some damage.  In order to determine what went wrong, we will perform a root cause analysis.  A thorough root cause analysis built as a Cause Map can capture all of the causes in a simple, intuitive format that fits on one page.First we’ll look at the impact to the goals.  An emergency landing is an impact to the customer service and production/schedule goal.  Additionally, the damage to the landing gear is an impact to the material/labor cost goal. We begin with the impacts to the goals, then ask “Why” questions to fill out the Cause Map.  For example, the damage to the landing gear occurred because the pilot steered the plane off the side of the runway.  The pilot steered the plane off the runway because of an obstruction at the end, and because of control issues, which occurred because of a failure of multiple cockpit systems.  The failure of these systems also caused the emergency landing.

The failure of the cockpit systems was caused by the battery power being depleted and not being recharged.  This occurred because the battery was powering four systems, and was disconnected from the main battery charger.  This happened because the standby power selector switch was moved to the “BAT” (or battery) position.  The standby selection switch was moved to battery because that is what procedure called for when the “Standby Power Bus OFF” light is illuminated.  The light was illuminated due to a relay failure, of unknown cause.

At this point, a problem becomes clear.  A pilot following procedure should not result in an emergency landing for a plane.  Thus, we have a procedural problem.  We will use a Process Map to draw out a procedure for more clarity to see where the specific issue lies.

Based on general information presented by the National Transportation Safety Board (NTSB), the illumination of the “Standby Power Bus OFF” light indicates a loss of power to the standby AC or DC bus.  If this occurs, the standby power selection knob should be turned to “BAT” (battery).  The battery should provide standby bus power. If the “Standby Power Bus OFF” light goes out, the standby power selection knob should be turned to “AUTO” which restores the battery charger.

Written in a paragraph, it can be difficult to see where the issue is.  But if we put it in a Process Map, we see a decision box for “Standby Power Bus OFF light remains illuminated.  If the answer is yes, we follow the procedure outlined above.  But if the answer is no, there is no procedure to follow.  This is the position the pilot of Flight 268 was in.  The “Standby Power Bus OFF” light went out, so the pilot left the standby power selection knob on “BAT”.  This drained the battery, resulting in the failure of various cockpit systems, as discussed above.

Even more detail can be added to this Cause Map as the root cause analysis continues. As with any investigation the level of detail in the analysis is based on the impact of the incident on the organization’s overall goals.

Salmonella Contamination in Peanut Products

Download PDFBy ThinkReliability Staff

In January, 2009, health officials discovered Salmonella typhimurium in a jar of peanut butter.  The Food and Drug Administration (FDA) was able to trace the contamination back to the Peanut Corporation of America (PCA)’s  Blakely, Georgia plant.   A root cause analysis built as a Cause Map can show the causes of this tragic, preventable incident in a simple, intuitive format that fits on one page.

To begin our root cause analysis, we start with the impact to the goals.  The peanut products contaminated with salmonella resulted in 700 reported illnesses.  This is an impact to the safety goal.   Also, PCA received a $14.6 million fine for shipping products contaminated with Salmonella.  This is an impact to the regulatory goal.  There are other goals that were impacted as well, but we will begin with these two.

People were sicked and PCA was fined because peanut products contaminated with Salmonella were shipped to consumers.  These products were able to be shipped because they were retested for Salmonella until the results were negative (this is illegal, by the way) and several lots of product were contaminated.

The product lots were contaminated because the processing line was exposed to Salmonella and was not cleaned after the contamination.  The two likely ways that the line was contaminated is either by exposure to rain (which can carry Salmonella) or by cross-contamination of finished product (which should have any microorganisms destroyed in the roasting process) and raw product (which hasn’t).  Additionally, the roasting process in the Blakely plant was inadequate to kill Salmonella.

The plant suffered from inadequate cleaning, which resulted from a line that was not able to be adequately sanitized, and from inadequate supervision.  The FDA had last inspected the plant in 2001, which is typical due to understaffing.   However, they might have visited sooner if the Salmonella test results (the ones that were re-done to get negative values) were shared with the FDA.  These results were not shared with the FDA, which is common industry practice.    State inspectors found only minor issues.

None of PCA’s customers appeared to have visited the site, possibly because they relied on an audit firm’s “superior” ranking.  This audit firm was paid by PCA.  There was also inadequate supervision due to inadequate leadership at the plant, which had no plant manager for a portion of 2008, and was missing a quality manager for four months.

Even more detail can be added to this Cause Map as the analysis continues. As with any investigation the level of detail in the analysis is based on the impact of the incident on the organization’s overall goals.