Hot water heartbreak: gas heater explosions.

LP gas is one and one-half times heavier than the weight of air, and it tends to spread along the floor and accumulate where a source of ignition can cause it to explode.

Liquid propane (LP) gas water heaters have achieved widespread acceptance as energy-efficient producers of hot water for many U.S. homes. However, they are extremely dangerous. Explosions due to defective controls or improper maintenance are a major source of death, injury, and property damage. The U.S. Consumer Product Safety Commission (CPSC) estimates that gas-fired water heaters caused 5,100 fires, 30 deaths, and 360 injuries in 1993 alone.(1)

In many LP gas explosions, the victims are killed or suffer permanent disfigurement. For example, Robert Kroboth was vacationing at his mother's summer cottage in New York state when he went to the basement and attempted to light the pilot on the water heater. As he struck the match, he touched off en explosion and suffered severe burns over large portions of his body.(2)

Investigators determined that the heater's gas control had been contaminated, causing the safety valve to fail. For several hours before the explosion, LP gas had spilled onto the basement floor. Yet Kroboth could not see the spillage nor smell it.

Further inquiry revealed that both the gas control manufacturer and the gas company had known for more than a decade that the gas control was prone to contamination and leaks. In fact, by the time Kroboth was injured the manufacturer had already lost several lawsuits stemming from similar injuries. Rather than provide a consumer warning, the manufacturer had simply closed up shop.

The chemical composition of LP gas makes it inherently more dangerous than natural gas. Natural gas is lighter than air. If it leaks, it tends to vent up the flue of a water heater and spread harmlessly to the outside. LP gas, however, is one and one-half times heavier than the weight of air. Instead of venting, LP gas tends to spread along the floor and accumulate where a source of ignition can cause it to explode.

The chemical tendency to ignite is exacerbated by the location of most LP gas furnaces and water heaters: residential basements, where ventilation is poor.

Plaintiffs' lawyers handling LP gas cases must determine the cause and origin of the fire or explosion. Experts who can identify a fire's cause and origin are available nationwide. They can establish the center of the explosion by viewing the debris. These experts generally begin their investigation by inspecting the gas control to determine the position of the water heater's gas cock knob and thermostat.

There is a single gas cock knob on top of the control. A thermostat inside the control is typically adjusted by a knob on the face of the gas control itself. If the investigator can verify the exact position of these knobs, he or she can usually determine the cause of the leak. It is extremely important to make sure that no one manipulates the gas cock knob or thermostat.

When examining the controls, have the investigator look for knob damage or deformation, water damage, heat distortion that may have caused a partial melting of the plastic components, and other signs of abnormal wear. Note the markings on all controls and whether any damage or deformation appears. Bring along a camera or a video camera with a macro lens, and photograph the controls and gas connections to document the conditions that existed at the time of the explosion.

Have the investigator prevent any contamination from entering or leaving the controls by taping or plugging all control inlets and outlets. Before testing the controls --or any other system components, for that matter--make sure that the investigator has a good general understanding of their potential defects.

Before disassembling the controls, discuss with your investigator whether using radiography can help identify the cause of gas valve failure. Radiography is a simple procedure that involves taking an X-ray of the controls. To take the X-ray, the expert will typically remove the control from the water heater and take it to an engineering firm that uses X-ray equipment that can penetrate metal. The X-ray will show whether the safety valve is open or closed. If the valve is open, the X-ray may also indicate whether structural defects or particle build-up prevented it from closing properly.

If the controls are disassembled without X-raying them first, the disassembly process may alter the internal workings of the controls so that the cause of the system failure cannot be identified.

Note that the presence of faulty control knobs does not in and of itself establish the cause of the explosion. Wear or damage may signal that the control knob may be stuck in the on position. The damage, however, must be located near the knob-stop device on the control. If the damage is not in that area, it is less likely that the damage is causally related to the leak, and further investigation is warranted.

The expert will try to identify the center, or epicenter, of the explosion in order to determine where the greatest concentration of gas was located. The epicenter will often indicate which gas appliance caused the leak. The char pattern, or burn pattern, will be more narrow at the epicenter and will broaden out from that point. Once the expert has determined the epicenter, photograph or videotape its location.

Pressure tests

Have pressure tests for leakage in the gas distribution system taken before touching any water heater components. These tests may be done by local LP gas dealers, many of whom have been well trained by insurance carriers and industry trade associations.

If LP gas dealers perform these tests, be aware that their first concern is to protect themselves from any liability, which may skew the results. A better idea is to use a former gas company employee or an expert who lectures to the LP gas industry. Although these people can be difficult to find because of the potential conflicts of interest, they are accessible and known to attorneys practicing in this field.

Gas dealers will often conduct monometer tests to pinpoint leakage in the gas system. Monometers measure the pressure within the LP gas piping. Frequent culprits are safety valve leaks in gas controls or loose fittings in gas lines. Applying soap suds to joints or connections of piping to controls may reveal a leak if the soap bubbles, but placing a monometer on the system (usually at a stove) and monitoring the reading is a much more accurate method of determining the existence and quantity of a gas leak.

The first- and second-stage pressure regulators should also be tested to determine their operating setting and stationary or lock-up pressures. The first-stage regulator is typically found on top of the gas tank and reduces tank pressure of about 100 pounds per square inch (PSI) to 10 PSI. The second-stage regulator is typically mounted at the house and reduces the pressure from 10 PSI to about one-half PSI (also referred to as 14 inches water column).

Finding the cause

Before you can conclude that LP gas precipitated the explosion, investigate all other fuel sources present at the scene of the explosion and rule them out. Other sources might include sewer gas or flammable liquids stored in the basement, such as gasoline.

Once you have determined that LP gas started the blaze, you should identify what part of the LP system broke down. But to understand a typical system malfunction, you must first understand how the system operates correctly.

Gas water heater controls have an internal safety valve that is spring-loaded. The valve also has an internal gas cock safety valve seat, electromagnet, and thermocouple. When the pilot is lit and the operator holds down the button on top of the control's gas cock knob, the pilot flame will heat the thermocouple.

As the thermocouple heats, it creates a small source of electric current that is transmitted to an electromagnet, which holds the safety valve open during operation. The safety function is activated when the pilot light is extinguished. When the pilot flame goes out, the thermocouple cools, releasing the spring-loaded safety valve to a fully shut position.

Most LP gas explosions occur when the gas safety valve fails to close. The American National Standards Institute (ANSI) requires the controls to

1. regulate gas burners equipped with thermostatic controls;

2. manually manipulate the "on," "pilot," and "off" settings; and

3. incorporate a 100-percent safety shutoff mechanism, which turns off the flow of gas to the pilot and the main burner in case the pilot light is extinguished.

The 100 percent safety shutoff device is also required by the American Gas Association (AGA). This mechanism is the gas control's most important element. If this device fails to close fully, unburned gas can flow directly into a consumer's basement.

This type of emission can occur even if the opening is very small. For example, a safety valve seat measuring three-quarters of an inch in diameter that is cracked open only four-thousandths of an inch can leak enough liquid propane gas to burn 50,000 BTUs per hour. (By way of comparison, four-thousandths of an inch is about two-thirds the thickness of photographic film.)

Gas pressure buildup is another possible ignition source. This buildup is frequently caused by pressure regulator freeze-up or by contamination of the regulator seats. Water in the regulator can cause it to seize up. This frequently happens if the regulator is improperly installed with the vent portion aimed up.

The pressure regulator contains regulator seats, which are valve components that open and close. If the regulator cannot close completely or is "frozen" or "stuck open," excess pressure may result.

Causation can also be linked to ethyl mercaptan, an odorant added to LP gas by suppliers. It is intended to act as a warning agent to alert people in the area to its presence and to prevent accidental ignition. The odorant smells sulfuric, like rotten eggs.

Unfortunately, ethyl mercaptan frequently fails to warn because it attaches to the concrete walls or floor of a basement or to the inside of a new LP gas tank. This phenomenon is referred to as "odor fade." Odor fade occurs primarily as the result of chemical oxidation of the mercaptan odorants or adsorption of both the mercaptan and the sulphide odorants into the LP gas. In addition, many people confuse the odor of LP gas with other chemicals and fail to recognize the olfactory warning.

The LP gas industry is currently conducting testing to determine how quickly odor fade occurs. But until the industry resolves the problem, it will continue to contribute to untold injuries and deaths each year.(3)

A key part of your investigation involves interviewing victims, eyewitnesses, medical and police personnel, and gas suppliers and service technicians. Determine who was at the fire scene, what they observed, and what actions they took, if any.

Most important, find out if anyone tampered with physical evidence, however inadvertently. Statements from all witnesses about the events and conditions around the time of the ignition will be invaluable in your investigation.

Obtain a list of the gas controls that have been recalled by the manufacturer or the CPSC. The agency operates a toll-free consumer hotline. For more information, call [phone] and follow the prompts.

A short list of recalled gas controls includes the following:

Honeywell, Inc., models V5130, V8280, V4136

V4146, V5118, V5189, C5133, C5134, CS5133,

CS5134, V7284, V8129, V8136, V8139, V8146,

VS8133, VS8138, VS8141.

Robert Shaw Unitrol water Heater Control model A-1, 110, 200.

White-Rodger Division of Emerson Electric (Wraco) model series 3700.

Both Honeywell and Emerson Electric re-called their controls because of manufacturing defects in design and composition that compromised the structural integrity of the devices. These flaws have caused the knobs to become stuck in the on position, resulting in leaking gas if the pilot light goes out. Both companies have redesigned their knobs and upgraded the plastic material used to make them.

Assigning liability

The results of your investigation must be correlated with codes, regulations, and industry practices to determine liability. In these cases, claims of negligence, failure to warn, strict liability, and breach of warranty may apply.

Identifying defendants in these cases can be difficult. For example, an untrained investigator may assume that gas controls that comply with ANSI standards and are AGA-certified show significant evidence of due care. Unfortunately, this is not always the case.

ANSI standards are performance standards. They neither describe how the safety devices should be designed nor establish the materials for the manufacture of components. The standards say that when the pilot is extinguished, gas flow through the controls must be automatically terminated. ANSI testing does not contemplate some of the reasonably foreseeable conditions under which controls operate.

In Maertens v. White-Rodgers Division of Emerson Electric Manufacturing Co., a gas leak was caused by excess wearing of the internal keys of the gas cock knob.(4) They were made of an inferior grade of plastic and wore out as the knob was fumed. The worn keys allowed the knob to remain pressed farther down than it should have been when engaged in the on position. When the pilot went out, the safety valve could not close because the knob was stuck in a down position.

The inexpensive plastic that Emerson Electric and Honeywell used for the controls is often used for toys, refrigerator door shelves, and plastic knives and forks. It has poor abrasion resistance and low tensile strength.

The laboratory testing performed on the knob under the ANSI standard involved fuming the knob mechanically without applying downward pressure--precluding any possibility of wearing. But in the field, the operator--leaning over the control--always exerts some downward pressure, which in normal use can literally peel away parts of the knob. As a result, the knob passed the ANSI standard test but failed in the field.

Apparently, when engineers designed the controls, they did not consider the gas cock knob as an integral component of the pilot safety system. As a result, they selected materials and determined size and shape without adequately considering safety or analyzing possible failure.

At an additional cost of about one-half of one cent per knob plus the cost of a hazard analysis, the control was fixed.

Another defect common to most gas controls--particularly those involved with LP installations--is particle buildup in the safety valve cavity. As discussed earlier, this cavity is where the safety valve is placed. The valve's function is to close off the flow of gas when the pilot is extinguished. If the valve is blocked, the safety function of the control will fail.

Valve manufacturers have known for decades that buildup in a control can cause safety valve failure and result in gas explosions. They have also known that copper tubing is usually used in LP gas installations and that a chemical reaction occurs between the copper and the sulfur in the gas flowing through the tubing.

The reaction generates a corrosive called copper sulfite. Copper sulfite has been known to flake from the interior walls of the gas line, flow into the control, and collect on the safety valve. When the pilot is extinguished, sulfite flakes can prevent the valve from closing completely.

This problem is particularly serious in old gas systems where the gas line drops from the ceiling and where appliances have been replaced or relocated. (Old copper lines that have been moved tend to crack on the inside, causing excessive flaking.) Some control manufacturers have recently recognized the need for an in-line filter. Both Emerson Electric and Robert Shaw Controls now manufacture water heater controls with a baffle or filter designed to keep particles out of the safety valve.

Duty of suppliers

Be aware that gas suppliers have a duty to inspect gas systems and warn customers of dangerous conditions. This duty emanates from industry custom and practice, and from the LP gas "bible," better known as the National Fire Protection Association's (NFPA) Code 54.

For example, the Liquid Propane Gas Association, the trade association for LP gas dealers, has promulgated Safety Rule 102-82. This rule is referred to as the out-of-gas procedure. It requires delivery people to relight gas appliances and inspect them to determine that they are properly installed, in working order, and not subject to a product recall. This duty is triggered when a customer runs out of gas, which explains its name.

If there is a defect in a customer's system, the procedure requires delivery people to red-tag the system, warn the customer, and repair the defect, if possible. Failure-to-perform claims have been the basis for significant verdicts against gas suppliers.(5)

Other procedures are outlined in NFPA's Code 54. Its guidelines require delivery people to examine all newly installed gas systems and all old systems that have been shut down and reopened.

Obtain the "route card" from the local gas company, which contains the list of all deliveries and service calls made to the premises. This along with individual sales receipts will help you determine whether any Code 54 violations have occurred. Sales receipts and route cards should identify the quantity of each sale. From that, you can determine whether or not there was an out-of-gas call or other occasion when the system had to be fumed off. The event triggers the inspection duty.

NFPA 54 has been adopted by most states and incorporated into their delivery rules and regulations. A violation of NFPA 54 in most jurisdictions is considered prima facie evidence of negligence.

NFPA [sections] 5.5.6 requires that a sediment trap or drip leg be installed on all gas systems that run uphill or "upstream" to the automatic controls, such as on a furnace or water heater. Despite this regulation, many installations are still completed without adding a sediment trap. This often results in particle buildup in the control, causing safety valve failure.

Before 1986, [sections] 5.5.6 mandated sediment traps only "if dirt or foreign material is a problem." In 1986, sediment traps became mandatory in all installations. Most LP gas service personnel will confirm that they are aware of the requirement.

The Kroboth case illustrates the sediment trap liability.(5) Copper sulfite had contaminated the unit's valve, preventing it from closing completely and allowing gas to leak from the unit and pool on the floor.

Although gas company staff had not installed the system, they had serviced it and therefore had a duty to red-tag it because it had no sediment trap. This duty was based on industry custom and practice. Although defense counsel denied any obligation to inspect or warn, the defendant managers acknowledged responsibility by deposition, and the case was settled.

The duty to inspect and warn begins when the gas in a house is fumed off or installed for a new customer. Failure to perform this inspection and provide adequate warning may be considered a deviation from industry practice and is evidence of negligence.

It can be difficult to obtain expert witness testimony identifying the nature and extent of duty in this kind of case. And it is not easy to obtain evidence of industry practice from industry personnel. It is possible, however, to obtain testimony from independent gas specialists and from managers employed by the defendant gas supplier. If they are honest, they will admit that this duty to inspect and warn exists. The Kroboth case is a perfect example of this type of negligence.

In addition, gas companies' duty to inspect and warn is well documented by the industry's trade association newsletter, the National LP Gas Newsletter. It often discusses this subject and can be used to cross-examine witnesses or to substantiate the positions of plaintiffs' experts.

Identifying owner responsibilities

Naturally, a property owner has the responsibility not to abuse the gas controls. Owner liability is generally pleaded by the defendant as a defense. Owners may do foolish things because they don't recognize the hazard; if they attempt to force the control by applying a tool to it, this action has been known to cause product failure and a resultant leak.

The most typical defense raised is that the owner used a pliers on the gas cock knob. This can damage the knob, causing sufficient deformation to cause a gas leak. Owners' responsibility depends in large part on their knowledge of the hazards and risks associated with LP gas water heaters and whether they are landlords renting the property or are owner/occupants.

With thorough investigation and testing, plaintiffs' counsel can identify the cause of the explosions as well as the negligent parties involved.

Notes

(1.) U.S. CONSUMER PRODUCT SAFETY COMMISSION, 1993 RESIDENTIAL FIRE LOSS ESTIMATES (1995).

(2.) See Kroboth v. Honeywell, Inc., 6 ATLA PROD. LIAB. L. REP. 109-10 (July 1996).

(3.) Stanley E. Karon, Liquid Propane Gas Odor Fade: The Warning Agent That Doesn't Work, 13 TRIAL DIPL. J. 15 (Spring 1990).

(4.) 23 ATLA L. RER 422 (Nov. 1980).

(5.) Kroboth, 6 ATLA PROD. LIAB. L. RER 109-10. See also Craft v. Honeywell, Inc., 11 ATLA PROD. LIAB. L. RER 52 (Apr. 1992); Blossman Gas Co. v. Williams, 375 S.E. 2d 117 (Ca. Ct. App. 1988).

(6.) Kroboth, 6 ATLA PROD. LIAB. L. REP. 109-10.