Wilo USA, a provider of pumps and pump solutions for...
Numerous other dangers lurk around a plant, awaiting the unwary. Electrical shock injury is common, as are injuries from falls and accidents resulting from the conflicts between the rolling stock around the plant. Burns from hot asphalt oils also are fairly common, though rarely fatal. Portable asphalt plants are especially vulnerable in these areas because of the labor intensive environment and the number of people involved when they are being moved.
The following accidents occurred at portable asphalt plants in the past five years. Again, they weren’t the only ones.
Case No. 1
A portable drum plant was being torn down in preparation for a move to a new location when a 30-year-old plant mechanic was severely injured by a fall from the crane ball he was riding. The victim had been on top of the asphalt silo disconnecting the slat conveyor and then rigging the picking cables for the holding silo. Because the silo had no access ladder, the man was forced to find another way to the ground after hooking a 100-ton crane line to the silo rigging.
As they had done many times in the past, workers moved a 9-ton crane next to the silo and the victim climbed onto the ball. On the trip down, he lost his grip on a greasy cable and fell 20 ft to the ground.
Case No. 2
A 40-year-old plant operator was killed when he was electrocuted while unwiring a 10-hp motor on a feeder collecting conveyor. The plant was running two shifts at the time. The night operator had experienced problems with the belt’s starter. This resulted in one set of starter contacts being burned out and rendered inoperable. No replacement contacts were available at the time, so to get running, the operator simply wired around the bad set of contacts, leaving one leg hot at the motor. Around mid-day on the next shift, the motor lost a bearing and began to squeal, requiring immediate replacement. The day operator, unaware of the night man’s wiring modification, failed to turn off the circuit breaker to the motor and lock it out as required by law. Unfortunately, he was standing in 2 in. of water when he unwired the hot leg and as a result, was electrocuted to death.
Case No. 3
An 18-year-old novice ground man was severely injured when he attempted to grease the head roll on a collecting conveyor. The chain drive unit was running at the time and the guard had been removed earlier in the day to facilitate the replacement of a broken chain.
In order to grease the drive side of the head roll, the victim had to reach through the moving chain to access the bearing which was hidden behind the drive sprocket. When he attempted to pump the grease gun, his hand became entangled in the moving chain. In an instant, the victim’s hands were drawn into the chain’s pinch-point and around the drive sprocket. Both hands were severely mangled, requiring many operations including the amputation of several fingers on each hand.
In the final analysis, all three of these accidents were due, in part, to negligence on the part of the victim and to a greater degree, on the failure of their respective companies to provide clear and strict guidelines for use in the situations encountered by each of the victims.
Case No. 1
It is simply illegal to ride any cable on a crane unless a suitable man-basket and safety restraint belt are used. This particular plant had been moved numerous times over its career. Additionally, there was plenty of time to install an approved safety ladder to provide access to the top of the silo.
At this company, it was an accepted practice to ride the crane ball. Evidently, no one gave any thought to the consequences until after the accident. The truly baffling part of this incident is the fact that the OSHA-required safety equipment was on the back of a truck within 50 ft of where the victim hit the ground.
On a related topic, people routinely climb around on asphalt plants when they are being torn down, and surprisingly, few of them are even aware that OSHA regulations require the use of an approved safety restraint belt whenever a person is over 6 ft from the ground. Other people shy away from their use because the devices are awkward and uncomfortable.
This seems a petty consideration when compared with the discomfort that results from a high-speed impact with the ground after falling from the top of an asphalt holding silo. If comfort were a valid consideration in safety issues, one could speculate that there would be a lot more corpses laying around.
Additionally, few people voluntarily wear hard-hats, safety glasses and gloves.
Case No. 2
While failure to allow published OSHA lockout-tagout regulations was the direct cause of this accident, this incident is included here to demonstrate the indifference with which some people may approach potential electrical shock hazards.
In this case, the victim didn’t even bother to turn off the circuit breaker as required by even the most basic safety concepts. While we will never know for sure, it is easy to speculate that his reasoning was probably that as long as no one pressed the start button for the collecting conveyor, the motor wiring would be dormant.
A contributing factor in this accident was the failure of the night operator to inform the day operator of the potentially lethal condition he had created when he by-passed the motor’s starter contacts. Communication is a key safety issue at any hot-mix asphalt facility. The simple practice of keeping a daily plant diary may have saved a life in this case.
Case No. 3
Two things combined to cause this accident. First, the ground-man was not sufficiently trained in his job to realize the dangers posed by moving equipment, especially chain drives. Being young and eager to impress his new boss he made a poor choice that will haunt him for the rest of his life.
The second and more important issue in this case is the failure to replace the guard over the drive unit when repairs were finished earlier in the day. With trucks backed up and the paving superintendent screaming for hot-mix, it’s not hard to see how the pressure of production quotas probably influenced the operator’s decision to leave the guard off.
In retrospect, it was a decision regretted by everyone involved. OSHA levied heavy fines in this incident and, of course, the lawsuits continue.
Other safety issues
One area of safety that is routinely compromised at portable asphalt plants is the conflict between truck traffic and the needs of the loader operator to access his stockpiles. Small pits, filled with the aggregate for up-coming jobs, sometimes offer little space to set-up a plant. Compromises must often be made that can and do jeopardize safety.
One common practice is to run the truck traffic behind the loader at the feeders until enough aggregate can be used up to permit the construction of an alternate path. In the heat of the battle, the loader operator is a busy person. Sometimes, hurried past the point of conscious thought by the need to keep up with the plant, the loader operator backs away from the feeders without checking behind the machine. Because loaders have the right-of-way in almost all pits, the operator gets away with this most of the time, but not always. It seems obvious that the utmost care must be exercised during the time the trucks are vulnerable, yet each year trucks are wrecked and their drivers hurt.
One method of combating this problem is to have a meeting prior to the start-up of operations on the first day. The loader man and all truck drivers should discuss the ways to keep their respective activities safe for others and work out a plan that is acceptable to everyone involved.
One suggestion, a common C.B. radio in the loader and one in each of the trucks can go a long way toward eliminating conflicts. Again, communication is often the key to safety.
The issue of careless people is somewhat more difficult to deal with, since some folks only learn in the aftermath of an accident. If a person is consistently careless and puts themselves and other at risk, perhaps it’s time to replace the employee.
One common thread in all accidents discussed in Parts I and II was a disregard of safety issues in deference to production pressures. Asphalt plant operators often feel tremendous pressure to produce by any means possible. Unfortunately, this shifts the focus off safety and onto money. Perhaps a clear-cut set of guidelines dealing with a company policy on safety issues should be drawn up and distributed to everyone involved with the plant. Be sure to include the paving superintendent, this individual can exert enormous pressure on the plant operator without even realizing that he is doing it.
Remember, everyone wants to do a good job and will sometimes go to great lengths to get results. Often, to that end, things are done that normally would not even be considered. Once again, communications is the key to safety.