In March 2005, an explosion at the BP refinery in Texas City, Texas, killed 15 workers and injured 170. Kate Murray-Del Aguila, an industrial hygienist at BP, was assigned to work on the company’s response to the accident. Recalling the incident last month at AIHA’s Fall Conference, she said, “I thought it would be the biggest response I’d ever see in my career.”

But five years later she found herself working on an even larger response following the explosion and fire on the Deepwater Horizon oil rig, which resulted in the deaths of eleven workers and the largest-ever oil spill in U.S. waters. After three months the leaking well in the Gulf of Mexico was finally capped, but cleanup efforts continued far longer and required industrial hygiene expertise and oversight to keep workers safe.

Murray-Del Aguila recounted her experiences working on these large-scale responses during a session at the Fall Conference in San Antonio on Oct. 24. Her presentation identified several lessons that IHs can apply before and during a response and memorably captured the challenges of coordinating hundreds of responders from multiple companies over a period of months.

The preparations for an emergency response must begin well in advance of an incident, Murray-Del Aguila said. Since most responses require IHs to work with local fire and emergency departments and hire contractors to conduct monitoring and perform other industrial hygiene tasks, she urged attendees to develop relationships with staff from these organizations. “The first time you meet them should not be at a big event,” she said, adding that an IH must also honestly assess the strengths and weaknesses of the company’s OHS contractors. “You may have great relationships with local IH and safety consultants, but are they experienced in emergency response? What is their specialty? Do they have the ability to scale up?”

During the early stage of a response, industrial hygienists and OHS professionals typically act as “integrators,” helping company HR staff reach workers’ families and getting representatives from the government affairs department to respond to questions from the media. One of Murray-Del Aguila’s tasks was to help contractors figure out which hospitals the injured should be sent to and how to contact their families.

In large emergencies, the rapid escalation of the response can quickly strain logistical capabilities. BP’s response to Deepwater Horizon started with 50 people in the response command center. Within thirty days, Murray-Del Aguila said, there were 50,000 people involved at every level of the response, sapping resources and supplies. A response command center could be centrally located among responding companies but still be miles from the site of the emergency, so an IH needs to have already thought about how to get resources from one place to another.

The media’s focus during the Deepwater Horizon cleanup centered on chemical exposures, but fatigue and stress proved to be greater hazards. To make sure workers were getting proper rest, BP used horns to signal when shifts began and ended. Even well-trained responders can become overwhelmed in a large-scale event. “People react differently to the stress of emergency response,” Murray-Del Aguila said.

While monitoring data showed that Deepwater Horizon cleanup workers did not need PPE, it proved difficult to convince the public that Tyvek suits and respirators would actually put workers at greater risk of harm from heat stress, Murray Del-Aguila said.

Having clearly established monitoring protocols ahead of time helped ensure that contractors would perform their tasks in a consistent manner and that everyone knew what to do if measured concentrations reached a certain level. Still, she stressed that observation of data collection in the field and a clearly defined process for validating all positive samples were vitally important, especially given the need to constantly share data with workers and the public. During the Deepwater Horizon cleanup, BP published real-time monitoring results every 12 hours.

“You can never get the data out fast enough,” Murray-Del Aguila said.

While the end of a response cannot match the intensity of its first days, Murray-Del Aguila stressed that clearly defined processes are necessary to govern the cessation of monitoring and the re-d​eployment of people and equipment.