1 A chlorine cloud as big as six football fields spewed from a factory Thursday near the site of the Reagan presidential library, forcing thousands of evacuations, backing traffic up for miles on closed roads and freeways and injuring three firefighters.
2 Chlorine escaped during most of the day from a 5,000-gallon, 30-ton tank at the Traveling West Textile Co., forming a greenish-yellow, potentially deadly cloud on the outskirts of this suburb northwest of Los Angeles.
3 Just after dark, a specially outfitted hazardous-materials squad was able to tighten a valve on the tank.
4 'They got a big wrench and tightened the valve,' said Battalion Chief Larry Whelan.
5 Earlier, firefighters directed a high-pressure, 80-foot stream of water on the tank, a process that caked the loose valve with ice, temporarily sealing the leak.
6 While the leak was stalled, the cloud over Simi Valley dissipated and the valve on the tank was tightened.
7 As a precaution, the valve was then capped, Whelan said.
8 At 7 p.m., the evacuation order was lifted, giving way to massive traffic jams in this city of 100,000 people.
9 Whelan said an estimated 11,500 people had been evacuated from offices and homes in a 15-square-mile area after the leak was reported at 7:40 a.m.
10 The evacuees included at least 1,400 students, 1,000 business workers and the 125-member staff of the Simi Valley Enterprise newspaper.
11 Three members of the Fire Department's hazardous materials team were taken to the hospital, Ventura County fire spokeswoman Susan Chandler said.
12 Two of them were treated and released; the other was kept for observation.
13 'We don't expect any major injuries or deaths,' Ms. Chandler said.
14 The gas from the factory at Madera Road and Easy Street settled in a huge cloud over the northwest part of the city, not far from the 100-acre foothill site where the $60 million Reagan library is to be built.
15 It spread slowly during the day, and was 100 feet by 600 yards by late afternoon, said Ms. Chandler.
16 Traveling West, which dyes bulk textiles, had been closing down the factory in preparation to move out of state, fire officials said.
17 Whelan said the tank was drained on Tuesday of all but 20 to 50 gallons of liquid chlorine used to treat plant wastewater before it was funneled into the sewers.
18 Chlorine and its compounds are used for bleaching in the paper and textile industries, for disinfecting municipal water supplies, for household bleaches and germicides and in the production of many organic and inorganic chemicals.

Chlorine escaped during most of the day from a 5 , 000 - gallon , 30 - ton tank at the Traveling West Textile Co . , forming a greenish - yellow , potentially deadly cloud on the outskirts of this suburb northwest of Los Angeles .
suburb
What is the suburb named?