Refinery and power company officials are trying to piece together why several Texas City plants lost power, causing shelter-in-place warnings, Tuesday school closings and emissions from plant flares that lit the skies over the coastal town.
The brief power outages, which occurred in two clusters starting around 9:30 p.m. Monday and 4:30 a.m. Tuesday, prompted BP, Valero and Marathon Oil to shut down their refining operations. Dow Chemical also shut down equipment at its Texas City chemical plant, which makes components used in consumer and industrial products.
Flare towers designed to burn off emissions glowed late Monday and in the predawn darkness Tuesday at BP's sprawling refinery and chemical complex. A fire broke out in one unit shortly after the facility lost power, but it was quickly put out with no injuries.
Dow Chemical said it had no emissions following its shut-down and did not need to flare. Valero said it only flared early Tuesday morning.
Texas City officials warned residents to stay inside beginning late Monday to avoid exposure to possible emissions. Texas City schools were closed Tuesday, and La Marque's opened late.
A Texas Commission on Environmental Quality investigator measured emissions with a handheld device at seven locations Tuesday morning. The measurements for volatile organic compounds -- a broad class of chemicals found in crude oil, pesticides and common solvents such as turpentine -- exceeded the instrument's capability, said Terry Clawson, an agency spokesman.
"Based upon our monitoring values, we believe that the city manager's decision to issue a shelter in place was appropriate," Clawson said, adding that the decision to lift the warning at noon on Tuesday was based on all monitoring data available then.
At least 25 people went on their own to Mainland Medical Center in Texas City complaining of upper respiratory distress, but only one was admitted and was in good condition Tuesday evening, said Kris Muller, a spokeswoman for the HCA Gulf Coast Division that owns the hospital.
Residents reported hearing explosions that sounded like transformers blowing out before the outages Monday night.
As a group of residents gathered near the BP refinery Tuesday morning, some were resigned to the hazards of living in one of the nation's largest gasoline refining hubs, which processes more than 800,000 barrels of oil per day.
"If you're raised here, you're familiar with this," said Daniel Bibbs, who grew up in Texas City. "It happens. You just have to live with it."
One of his neighbors was less philosophical.
"I'm moving to La Marque or Houston. Somewhere away from Texas City," said Valerie Hudson.
'It's a big leap of faith'
The facilities that reported outages must report any emissions to Texas Commission on Environmental Quality within 24 hours.
By Tuesday evening only Valero's data showed up on the agency's database, reporting release of an estimated 43,000 pounds of sulfur dioxide from emergency and startup flaring. Sulfur dioxide can react with other compounds to form ultrafine particles associated with heart and lung disease.
Neil Carman, air program director for the Sierra Club's Lone Star chapter, said it's better for an industrial plant to use flares to burn off pressurized gas during emergencies than to allow an uncontrolled venting.
But he is skeptical of industry-provided estimates of emissions during "upset events" -- non-permitted releases caused by lightning strikes, human error, startups and shutdowns -- because of they assume the flares are working at high efficiency.
"The big dilemma with flares is that there is no monitoring," said Carman, a former Texas environmental regulator. "It's a big leap of faith."
On Tuesday afternoon Valero, Marathon and Dow said power was restored and they were restarting operations as they determined equipment was operating properly.
BP said its 473,000-barrel-per-day refinery had only limited power by Tuesday afternoon, however, and it had not restarted most processes.
BP's refinery has on-site power generation capacity and generates more electricity than it uses. The other three facilities rely on power from the local grid, which is owned and operated by Texas New Mexico Power Co.
The outages Monday night appeared to be due to failure of equipment owned and operated by the plants, said TNMP spokeswoman Cathy Garber. The ones Tuesday morning occurred when a buildup of soot, dust, salt and other residues on transformers and insulators causeed TNMP equipment to short-circuit.
Normally rain washes away such residue, but this month's lack of rainfall apparently allowed the buildup, Garber said.
"High humidity late Monday night and early this morning, coupled with the buildup of residue, appears to have triggered the fault," she said.
TNMP crews borrowed Texas City Fire Department equipment on Tuesday to rinse off other equipment in the area to avoid similar problems.
CenterPoint Energy, which owns the power lines in areas surrounding the TNMP service area, said it has been rinsing off equipment because of similar concerns in the past week, particularly on Galveston Island.
The incident didn't affect gasoline prices, said Tom Kloza, an analyst with the Oil Price Information Service.
If it had occurred last month, or even a few weeks ago, it might have bumped prices up 5 cents to 15 cents a gallon, he said, but prices already are so high that consumers are cutting back their use in response.
"The bottom line is that we've seen this movie before," Kloza said. "Spring brings refinery maintenance, storm-induced shutdowns, and the various problems that come up when refineries come back from turnarounds."
(Chronicle reporter Cindy George contributed to this story.)
Copyright (c) 2011, Houston Chronicle. Distributed by McClatchy-Tribune Information Services.