A Tri-State Generation & Transmission official said Monday the company is no closer to identifying the cause of Saturday's incident at the power plant, which sent almost 20 workers to the hospital.
Between midnight and about 1 a.m. Saturday, 19 people working at the Tri-State power plant south of Craig went to The Memorial Hospital for flu-like symptoms, including nausea, coughing and burning eyes, Tri-State Communications Manager Jim Van Someren said.
He added he was unaware of any other conditions the workers may have had.
Everyone taken to the hospital was working inside the plant's third power unit on a $39 million environmental renovation. Tri-State plans to install new burners to limit oxides of nitrogen emissions, upgrade the plant's smokestack scrubbers and complete a variety of maintenance tasks.
All of the 19 workers who visited the hospital Saturday worked for subcontractors, and the vast majority worked for Broomfield-based Casey Industrial, Van Someren said.
He also clarified that not all were welders, as was reported Monday, but they were all in the same area when people started to feel ill.
An investigator with the Occupational Safety and Health Administration arrived at the plant Monday afternoon to start an inquiry into Saturday's incident, said Herb Gibson, with the OSHA Denver office.
The investigator will conduct further air monitoring, interview the sick and possibly look at their medical records to determine the cause of the workers' problems, Gibson said.
No more information on what happened to make people feel ill was available by press time Monday.
Van Someren said Tri-State has added extra ventilation to the area where workers became ill to mitigate any air contaminants that might be in the space. The company has not provided the workers with any respiratory equipment.
OSHA had received reports that workers at the plant had reported being sick before Saturday night, Gibson said. He did not know if their circumstances were in any way similar to what happened during the weekend.
Two employees - one hired by a subcontractor and a Tri-State employee - did get sick at the plant and were taken to TMH in ambulances within the last few weeks and before Saturday, Van Someren said. However, their situations had nothing to do with their job at the plant, he added.
"I can unequivocally confirm there have not been similar incidents in the last two weeks - or frankly ever - at Tri-State as what happened this weekend," Van Someren said.
He added Tri-State officials expect to have "full staffing" in the area where problems originated Saturday in the next couple of days.
He did not know if the same workers who were involved in the incident would return to the site.
A representative of Casey Industrial, the company that hired most of the workers who went to the hospital, said the company is referring all questions to Tri-State.
Collin Smith can be reached at 875-1794 or firstname.lastname@example.org.