Parks and Recreation Director Dies in Oxygen Deficient Atmosphere in West Virginia
The National Institute for Occupational Safety and Health (NIOSH), Division of Safety Research (DSR) is currently conducting the Fatal Accident Circumstances and Epidemiology (FACE) Project, which is focusing primarily upon selected electrical-related and confined space-related fatalities. The purpose of the FACE program is to identify and rank factors that influence the risk of fatal injuries for selected employees.
On July 15, 1987, the parks and recreation director of a small town in West Virginia died when he entered a manhole at the municipal swimming pool. The director had entered the 18 foot-deep manhole to instruct one of the life guards on how to switch from one sump pump to another.
The West Virginia Deputy Chief Medical Examiner notified the National Institute for Occupational Safety and Health (NIOSH), Division of Safety Research (DSR) of this fatality and requested technical assistance. This case has been included in the FACE Project. On July 17 and 20, 1987, a research industrial hygienist conducted a site visit and tested the atmosphere of the manhole for oxygen (02), flammability levels (CH4), and hydrogen sulfide (H2S) Interviews were conducted with the town mayor, the county medical examiner, the state deputy chief medical examiner, the police chief, the fire chief, two firemen who retrieved the victim from the manhole, two maintenance workers (parks and recreation department), the director of public works, the director of the wastewater treatment plant, a consulting electrical engineer (retained by the town), and the life guard who witnessed the fatal accident. A surrogate for the victim and two comparison workers were interviewed and photographs were taken of the accident site.
Overview of Employer's Safety Program:
The employer in this incident is a small municipality which has 75 employees in seven departments (public works, police, fire,--sanitation, parks and recreation, finance and administration, and water). The victim was the director of the parks and recreation department. Each department director reports to the mayor. The municipality has no formalized written safety program. Each department has operating instructions, e.g., the wastewater treatment plant has written procedures provided by equipment manufacturers. The only safety training provided is on-the-job training and use of common sense. There are no written confined space entry procedures. The municipality does have gas monitoring devices to test the atmosphere in confined spaces (sewers, lift stations, etc.) before entry.
Synopsis of Events:
On July 15, 1987, at approximately 1 p.m., the director of the parks and recreation department (victim) arrived at the newly constructed municipal swimming pool and was going to instruct one of the life guards on the procedure for switching sump pumps. The two sump pumps, which are used to pump subsurface drainage water from the pool area to a nearby creek, are located adjacent to the pool, at the bottom of a manhole (four feet diameter x eighteen feet deep with a two foot diameter manway). Metal rungs permanently fixed into concrete provides access to the equipment located in the manhole. The procedure for switching from one sump pump to another requires a person to enter the manhole, descend approximately nine feet, reach across to the opposite side of the four foot wide space, unplug one twist lock receptacle (not moisture proof or designed for use in wet environments) from one sump pump, and plug in the other sump pump to the 208 volt, three phase receptacle.
The director and the life guard proceeded to the sump pump manhole, where the director removed the steel cover from the manway. The director then entered the manway and descended via the fixed rungs into the interior of the manhole, which had not been opened in two months. The water in the manhole was approximately seven feet deep, since the circuit breaker feeding power to the sump pump motor had previously tripped. However, pump control power was still available in the manhole. When the director had descended approximately eleven feet into the manhole, he started shaking as if he was convulsing, let go of the rung he was holding on to, and fell backwards into the water. This was witnessed by the life guard who had remained on the outside of the manhole to observe the procedure for switching the pumps. The director had not touched electrical lines to the sump pumps before this occurred. His feet and lower legs were in the water.
The life guard did not enter the manhole to attempt rescue because he was concerned about electrical/electrocution hazards. The life guard ran to the maintenance/pump room area (approximately 100 yards) and reported to one of the maintenance men that the director was in trouble in the sump pump manhole. The circuit breakers were switched off, the fire department/emergency rescue was called, and a maintenance man returned to the manhole with the life guard. The maintenance man observed the director under the water and stated that the victim was unresponsive. The maintenance man entered the manhole (without respiratory protection) and at that time experienced difficulty breathing when he reached the water level (seven feet from the bottom). Because be was concerned about the electrical connections in the manhole, he exited the manhole and called to a co-worker to shut off the main breaker for the entire area. The main breaker was shut off (which removed the control power) and he re-entered the manhole (without respiratory protection); however, be was unable to reach the victim (not sure of the depth) so he exited again. The fire rescue squad arrived about the same time the maintenance man had exited the manhole for the second time. Two firemen entered the manhole (without respiratory protection) after being informed the power was off and removed the victim. The victim was unresponsive when removed and cardiopulmonary resuscitation was started immediately. The victim was transported to a local hospital where unsuccessful life saving efforts were continued for thirty minutes.
Cause of Death:
After completing an autopsy, the medical examiner determined that death was due to drowning in water. This occurred when the victim, who had arteriosclerotic coronary artery heart disease, collapsed after entering an oxygen deficient environment.
First report of fatality was listed as an electrocution. Upon investigating the incident, this was truly possible. This manhole was installed as part of the new pool construction in November, 1986. The contractor installed two sump pumps, two float switches (one for each sump pump), and twist-lock cord and plug connectors at the nine foot level for pump motor and pump control power. Neither the receptacles nor the plugs were approved for wet environments. The receptacles were taken apart by the electrical consultant hired by the city, and both had damage to the wiring connections and were heavily rusted. This deterioration is apparently what led to tripping the circuit breaker which fed the pump motor and the subsequent rise of water in the manhole.
The engineering consultant hired by the city conducted a voltage test (power restored) to measure the potential between the water in the manhole and the stainless steel pool. A copper wire was lowered into the water and the reading was less than .05 of a volt.
After the voltage test was completed, the sump pump was turned on and the water was pumped down to the one foot level. When the water level exceeds one foot, the pump turns on automatically.
The atmosphere in the manhole was tested on July 17, 1987, for 02, CH4, and H2S. The results of those tests were:
02 - 16.1% CH4 - Negative H2S - Negative
The manhole was closed on July 17, 1987, and reopened on July 20, 1987, and tested again. The results of those tests were:
10:00 a.m. 02 - 14% CH4 - Negative H2S - Negative
10:10 a.m. 02 - 17% CH4 - Negative H2S - Negative
Because the manhole has a lateral branch to an adjacent manhole, which opens to a creek, a static air condition will change rapidly to a dynamic condition when the top is opened.
On the day of the accident, the manhole had not been opened for two months and contained seven feet of water. From the atmosphere test readings on July 17, 1987, and July 20, 1987, it is likely that the 02 level was less than 10% when the victim entered.
Recommendation #1: The employer should take corrective action to remove the electrical hazard(s) from the sump pump manhole and bring the electrical system into compliance with the latest edition of the National Electrical Code (NEC).
Discussion: The electrical connections in the manhole are not approved or designed for use in wet environments. The connection box at the top of the manhole is not moisture proof. The twist lock receptacles (at the nine foot level) have been under water. The silt, corrosion, and electrolysis evident in these receptacles (less than nine months) are classic examples of what can occur when the wrong type of receptacles are used in an environment subject to moisture and/or flooding. The switching changeover operations from one pump to the other could be done by means of switches located in a covered protected area above the ground (not in the manhole) and need not be at the manhole site or in the public access area of the pool. Also, ground fault circuit interrupters should be installed.
Recommendation #2: The employer should develop comprehensive policies and procedures for confined space entry, where confined space entry is required.
Discussion: All employees who are required to work in confined spaces should be aware of potential hazards, possible emergencies, and specific procedures that are to be followed. Prior to entry into a confined space, the following should be addressed:
1. Is entry necessary? Can the task be completed from the outside?
2. Has a permit been issued for entry?
3. Has the air quality in the confined space been tested?
4. Have employees and supervisors been trained in selection and use of personal protective equipment and clothing?
5. Have employees been trained for confined space entry?
6. Is ventilation equipment available and/or used?
Recommendation #3: Public service employees (i.e. police officers, emergency rescue workers, and firemen) that respond to emergency situations involving confined spaces should be trained in confined space hazards and rescue procedures.
Discussion: Public service employees are required to respond to a wide variety of emergency situations. These personnel must be trained in and be aware of the following in order to be. properly prepared for emergencies involving confined spaces:
Recognition of Confined Spaces
Hazardous Atmospheres Oxygen deficient or enriched Flammable Toxic Irritant or Corrosive
General Safety Hazards Mechanical/Electrical Communicative Thermal Noise Structural barriers Limited space Size of opening(s)
Rescue Procedures Respiratory protection Protective clothing Harness Life lines Standby person