Poet Robert Frost wrote that good fences make good neighbors. But no fence is good enough to keep a sulfuric acid vapor release at one industrial facility from drifting onto neighboring property, such as an oil refinery.
In late 2011, a large refinery located on the U.S. Gulf Coast was on the receiving end of not one, but two SO2 vapor releases in as many days, both originating from a fertilizer plant next door, the refinery fire chief told colleagues at a recent corporate gathering.
“We have approximately 3,000 contractors at the refinery on a daily basis,” the chief said. “A lot of people were in the outside environment.”
The chief’s presentation covered procedures in effect at the refinery, which is spread out over hundreds of acres of land, to notify and protect workers during the vapor release emergency.
At about 5:30 p.m., the first of the two releases occurred. Air monitoring by refinery personnel detected approximately nine parts per million of SO2 in the area, the chief said.
“Based on that release, we had some interaction with the fertilizer facility to try to improve communication with them,” the refinery chief said. “That was one of our big challenges -- letting them know we were involved.”
A foggy morning greeted refinery personnel the next day, with temperatures about 40 degrees Fahrenheit. Heavy traffic moved along a state highway that separates the fertilizer plant from the refinery.
At 8:50 a.m. the fertilizer plant suffered a shut down of its sulfuric acid unit with significant release to the atmosphere. The prevailing wind normally blows from the southeast, which would have taken the vapor plume into a residential area.
However, the wind that day was out of the northwest, directing the vapor toward the refinery.
“That meant we had to deal with it,” the refinery fire chief said.
It would be at least three minutes more before the refinery was notified of the leak. Communications problems were immediately apparent, the chief said. Instead of speaking to the shift supervisor who becomes the incident commander in a toxic release situation, the staff physician at the refinery’s wharf facility got the notification.
“The shift supervisor was in his morning planning meeting,” the fire chief said. “When he didn’t answer his cell phone, the call rolled over to another number.”
When the chief learned about the release he contacted the fertilizer plant’s safety officer. Surprisingly, he knew nothing about the situation.
“I said ‘We’ve got a lot of activity,’” the chief said. “’We’ve got a vapor release coming our way. We’re getting reports of odors in the air’.”
At 8:58 a.m., surveillance video still showed steady traffic on the state highway separating the plants. Thankfully, the refinery has the authority to close it if the situation warrants.
“That alone was a major ordeal,” the fire chief said.
The lack of information forced the chief’s next action. He contacted the shift supervisor to urge immediate activation of the refinery’s toxic acid release procedures.
“What that meant was turning on the emergency horn and having all the contractors go to their mustering points,” the chief said.
The path to those mustering points is hardly direct.
“With the wind from the northwest, the contractors were instructed to move at a 90 degree angle away from the release in order to get upwind,” the chief said. Once they reached the mustering points, buses were brought in to transport the contractors out of the facility.
As for personnel working indoors, an announcement was made via radio to shelter-in-place. Management then proceeded to shut down the air handlers in each building, the chief said.
“The protocol for shutting down air handlers throughout the refinery worked in some cases, and didn’t work in others,” the chief said. “We are working on a new protocol.”
Not all control rooms throughout the facility came up to standard as a shelter-in-place location, he said. That has also been addressed.
Although these procedures had been discussed a great deal prior to the event, there had never been a drill conducted to cover these contingencies, the chief said.
“There was a lot of uncertainty,” he said. “Everything was in question.”
Communications issues continued to arise because not everyone on site got the word about the release. Not all contractors were equipped with radios. Also, not everyone heard the circa-1960s steam-driven emergency horn when it sounded.
“Due to the wind direction, people in the tank field and the wharf area couldn’t hear the horn blow,” the chief said.
About an hour after the first report of the release, perimeter monitoring indicated it was safe to sound the 'all-clear' signal. Officials restarted the air handlers and allowed those sheltering inside to venture outdoors. All contractors evacuated from the facility were allowed to return to their work.
“No respiratory distress was reported,” the chief said. “We didn’t have anyone go to the clinic.”
In the wake of the emergency, improved communications has received most of the attention, he said. More options exist to reach the shift supervisor in a crisis. The refinery’s main gate is now staffed around the clock as a central point of communications.
All contractors will be given company radios in future. A new notification system is being developed to better integrate the emergency horn, radios and computer options, the chief said.
“It will be a big update from the days when one blast meant run and two blasts meant hide,” he said.Poet Robert Frost wrote that good fences make good neighbors. But no fence is good enough to keep a sulfuric acid vapor release at one industrial facility from drifting onto neighboring property, such as an oil refinery.