The following is based on a true story, although the names of the participants have been changed. All the details may not be exact, and the name of the company involved has since been changed.

ABC Corporation was in the business of manufacturing wire. It had a pickling line that utilized a conventional waste treatment system to neutralize the acid and clarify the precipitated metal hydroxides. The clarifier was a rectangular tank, approximately 4x4 ft wide and 10 ft deep, with a flat bottom.

ABC operated the waste treatment system for some time, then decided to curtail the pickling operation and idle the waste treatment system. The system remained idle for more than a year before ABC reversed its decision, at which time the waste treatment system was to be refurbished and put back into operation.

The pickle house foreman decided to use two, young, part-time summer employees to manually empty the clarifier. (The solids at the bottom were calcified.) The part-time employees, Joe and George, were told to pump the water from the top of the clarifier down to the solids, then get inside and scoop/shovel the rest of the solids out of the tank. They were given no chemical safety training and were provided with no safety equipment, probably because the material inside the clarifier was thought to be relatively harmless (water and iron hydroxide sludge) .

After pumping the water out of the clarifier, Joe used a ladder to climb to the top (it had no cat walk). He threw several pallets onto the hard sludge at the bottom of the clarifier, then went inside, stood on the pallets and shoveled the sludge into a five-gal bucket. George waited at the top of the clarifier and removed the full buckets with a rope.

After a few bucketful, Joe noticed an irritating smell coming from the sludge. He told George, and they both decided to tell the foreman, Sam. Sam wasnt impressed with this story and told Joe and George to get back to work.

As they went deeper into the sludge, the smell grew stronger and more irritating. Joe and George returned to Sam and told him that they couldnt stay inside the clarifier without getting "high." Sam provided Joe and George with respirators. It is not clear what type of respirators were used, but best guess is that they were dust masks.

Joe and George found the masks useless and took them off. The smell got to be so strong that they took turns inside the clarifier. Neither employee was able to remain in the clarifier for more than five minutes without getting dizzy.

George was outside the clarifier when he heard a moan and the sound of a shovel hitting the side of the clarifier. He climbed up the ladder and looked down into the tank to see Joe slumped over on one of the pallets at the bottom.

George panicked and yelled as loud as he could for help. He climbed down the ladder and started running for the foremans office, shouting all the while that Joe had had an accident and was passed out.

Joes father, Ed, who also worked for ABC, heard of the accident and rushed to the scene. Several employees were standing around the clarifier when he arrived, confused as to what action should be taken.

Ed did not hesitate to climb up the ladder, jump into the clarifier and lift his son high enough that a co-worker could grab Joe and pull him to the edge. While the other workers were busy maneuvering Joe out of the tank, Ed passed out.

Ed was pronounced dead on arrival at the local hospital. Joe recovered and George was examined and released .

Causes of the Accident And Possible Prevention

All the evidence pointed to trichloroethylene as the chemical inside the clarifier. ABC had used a proprietary solvent containing trichloroethylene in various cleaning operations; but the trichlor was not supposed to be in the clarifier. Analysis of the sludge, however, confirmed that it was. Sources speculate that at some time during the idle period of the waste treatment system, an employee assumed that he/she could store or dispose of the trichlore by putting it into the clarifier.

OSHA made its investigation and issued numerous violations, which included failure to provide adequate training, safety equipment and tank labeling. In addition to chemical safety training under the hazard communication standard, the company should have provided training in safely entering and working in confined spaces.

One simple definition of a confined space is any area in the work place that a worker can enter, yet be encumbered in leaving. Any large, open-top clarifier or tank clearly meets this definition. Companies are required to review their operations, identify confined spaces and train their personnel in the safe entry and exit of such spaces.

Respirators for work in confined spaces must be the supplied-air type/ except for the very unusual situations in which the air hose would interfere with rapid exit from the space.

There are also instruments available for testing the air inside a confined space prior to entry. Such instruments are a good idea in all cases/ but are a must when it is reasonable to expect the confined space to contain toxic gases .

In the absence of easy egress, workers inside a confined space must wear a harness and hoisting equipment must be available for the rapid removal of the workers inside. Enough personnel must be outside the confined space at all times, so that rapid removal of those inside can occur.

The Resulting Law Suit

The story of Joe, George and Ed does not end here. The designer/waste treatment equipment supplier was sued by Eds widow for negligence in designing and installing a clarifier that had no means for easy egress. Further, it was charged that the designer should have anticipated that trichlore could accidentally get into the clarifier because the chemical was used elsewhere in the plant (although it was not used in the pickle house).

An expert witness for the plaintiff confirmed the charges and challenged the design of the clarifier because it had a flat bottom. It was the opinion of the witness that all clarifiers should have conical bottoms. With a conical bottom, the sludge would never have solidified, eliminating the need to send workers into the tank. Lastly, the witness maintained the clarifier should have had an escape hatch that could be opened from the inside so Joe and Ed could have gotten out quickly.

These allegations were made by an "expert" who had never designed a waste treatment system such as the one involved in the case.

Designers Must Inform Clients

All designers/consultants on waste treatment projects should be aware of this case. Warn all your clients that any open-top tanks that are part of a waste treatment system are to be considered confined spaces and that OSHA has specific regulations regarding entry and exit from same. Further, be sure to warn your clients that waste treatment systems must not be used for purposes other than those for which they were designed. Tanks containing dangerous chemicals must be labeled per OSHA regulations.

If a clients waste treatment system does not include cat walks/ladders for easy access to the tops of tanks, let him know such accessories are worth the extra cost, would ease operation of the equipment and may possibly prevent injury. Responsibility for the exclusion of such accessories should be placed on the client.

As for the escape hatch on the clarifier, if anyone can come up with a design that will function after years of corrosion and compensate for the varying depth of sludge inside the clarifier, he could probably get a patent and retire wealthy.

Companies with waste treatment systems using tanks that can become confined spaces should take note of this case and act immediately to prevent future tragedies.