当局正紧急试图阻止加利福尼亚州奥兰治县一个装满有毒化学物质的过热、受压和膨胀的油罐爆炸。
在这种被称为“前所未有”的情况下，该地区成千上万的人被告知周五离开家园，官员们发出可怕的警告，位于一个航天设施内的化学储罐处于“危机”之中，将会泄漏或爆炸。
“这是最真实的。这是我职业生涯中遇到的最糟糕的情况，”奥兰治县消防局(OCFA)局长Craig Covey周六在Garden Grove外的指挥中心告诉美国广播公司新闻，那里挤满了第一反应人员，旨在防止环境灾难。
加登格罗夫位于洛杉矶以南约30英里处。
在一个周日下午更新OCFA临时负责人TJ·麦戈文说，消防队员周六晚些时候对坦克进行了“侦察任务”,在此期间他们能够对坦克进行目视检查。
“他们发现的是储罐中的一个潜在裂缝，这可能会缓解那里的一些压力，”他说，并补充说他们现在正在“审查和验证”新信息。
麦戈文说，他们有信心裂缝不会导致任何泄漏，但他们正在监测空气。他告诉ABC新闻，团队将在周日晚上进行另一次任务，以确认有关裂缝的信息，如果数据是积极的，他们可能会缩小疏散区的大小。
OCFA在一篇文章中说后续更新疏散区以外的任何地区“目前都被认为是完全安全的，日常活动可以照常进行。”
“我们继续监控受影响材料的状况，并正在夜以继日地工作，以降低泄漏的风险，”位于花园林(储罐所在地)的GKN航空航天制造公司的发言人在给美国广播公司新闻的一份声明中说。“我们敏锐地意识到这一事件所造成的不确定性，并为给当地社区造成的持续干扰真诚道歉。”
声明进一步表示，GKN正与地方、州和联邦机构密切合作，以解决这一问题。
“我们的首要任务仍然是安全解决这一事件，以便居民能够尽快返回家园，”声明说。
周六，加州州长加文·纽瑟姆宣布奥兰治县进入紧急状态，以应对这一事件。
“奥兰治县居民的安全是重中之重，”纽瑟姆周六在一份声明中说。“我们正在动员一切可用的国家资源来支持当地的响应者，并确保社区拥有他们保持安全所需的一切。”
周日下午，纽森说他要求唐纳德·特朗普总统“发布紧急声明，支持奥兰治县的应对行动。”
根据美国广播公司新闻频道(ABC News)看到的一份内部简报备忘录，如今笼罩在大约10平方英里(约合10平方公里)疏散区上空的是两种担忧，一种是有毒气体可能会在附近飘散，另一种是危险的火球可能会爆发。
50，000根据疏散命令
强制疏散备忘录说，已经扩大到人口稠密地区的大约5万名居民。附近有多处公共设施，包括学校、医院、疗养院、消防站和执法站、关键基础设施和基本服务，目前都处于强制疏散和持续应对行动中。
疏散区的多条道路也被封锁，改变了该地区的交通路线。备忘录说，疏散中心已经在加登格罗夫、赛普拉斯、斯坦顿市政厅、阿纳海姆和布埃纳公园建立。
加登格罗夫联合学区表示，十几所学校已经暂时关闭，邻近疏散区的学校“出于谨慎”取消了户外活动。
尽管整夜努力冷却水箱，温度还是从77度攀升到90度。柯维证实了可能发生的两种情况:要么一个巨大的火球爆发，要么化学物质泄漏，影响成千上万的居民被迫撤离。
努力阻止灾难:“这方面没有先例”
当被问及解决这一问题的时间表时，柯维说:“我们不知道。每个人都问我这个问题，我很乐意给你一个答案。这方面没有先例。没人知道。”
官员们通过筑堤、筑坝和转移化学物质的流动为潜在的化学物质泄漏做好了准备，这是比爆炸更可取的选择，但即使这样也可能被证明是复杂的。
“如果我们烧毁一堆建筑和一堆房屋，那将是一场灾难，”柯维说。但是如果我们允许它流入海洋，造成生态灾难，我们也不希望这样。"
形势是如何发展的
根据奥兰治县消防局的说法，消防队员最初是在周四对GKN航空航天制造公司在加登格罗夫的泄漏做出反应，该公司从一个含有甲基丙烯酸甲酯的34，000加仑的储罐中释放出蒸汽，甲基丙烯酸甲酯用于塑料制造。
当局周四首次发布了疏散令，但随后当蒸汽条件改善时，疏散令被取消。然而，由于警方称之为“前所未有”的事件，疏散命令于周五重新发布并扩大。
周五，情况变得更加糟糕，官员们警告说，尽管没有活跃的气体泄漏或羽流，但储罐“处于严重危机之中”，无法得到保护。
三辆坦克受到影响
根据内部简报备忘录，GKN工厂的三个储罐受到影响。最令人担忧的是1号罐，它的阀门有故障，到目前为止，无法中和。由于容器内的化学反应，阀门卡住了。消防队员一直试图通过水冷来降低温度并保持稳定。
与此同时，现场的紧急救援人员一直在试图排除2号罐的故障，该罐含有与另一个受损罐相同的化学物质。现场官员已经在2号槽的甲基丙烯酸甲酯中加入了“中和剂”，以防止更严重的连锁反应。备忘录说，那个油箱看起来结构完好。
4号罐在结构上也很坚固，但是里面的东西的状态“未知”
备忘录称，当地消防和危险物质小组正在现场工作，以冷却34，000加仑的工业容器并进行清理，调查工作正在进行中，州应急资源也部分启动。美国环保署还向该设施派遣了两名现场协调员。
备忘录说，反应仍然活跃，迄今为止没有伤亡报告。
官员:“要么失败，要么爆炸”
在周五的新闻发布会上，当局阐述了形势的紧迫性。
“现在只剩下两种选择:第一，储罐发生故障，总共泄漏了大约6000到7000加仑非常有害的化学物质到那个区域的停车场。第二，燃料箱热失控并爆炸，影响周围装有燃料或化学物质的燃料箱视频更新星期五。
他补充说，“我们正在为这两种选择做准备——失败或爆炸，”他说。
官员们说，目前还不清楚居民何时能够返回家园。
“这是高度挥发性的，剧毒的，高度易燃的，”柯维在早些时候的新闻发布会上说，同时敦促人们撤离。“这不是预防性的。除非我身后的某个聪明人想出办法来缓解这一事件，否则这一切都会发生。这件事会失败，我们不知道什么时候。”
甲基丙烯酸甲酯是什么?
当局说，甲基丙烯酸甲酯是一种用于塑料和制造业的工业化学品，主要是一种呼吸刺激物。柯维说，估计大约有7000加仑的水留在处于危机中的水箱中。
根据美国环保署的说法，短期接触这种化学物质会导致皮肤和眼睛发炎，以及呼吸问题。
奥兰治县卫生官员里贾纳·钦西奥-邝(Regina Chinsio-Kwong)在周五晚上的视频更新中表示，爆炸可能导致化学物质以蒸汽形式释放，如果被吸入，可能会导致“严重的呼吸系统问题”她说，其他症状包括喉咙痛、流鼻涕、眼睛发痒和灼热，以及潜在的恶心和头痛。
GKN航空航天公司为商用和军用飞机制造发动机和起落架。美国广播公司新闻部对此事发表了评论。
在奥兰治县消防局的X账户上发布的一段视频中，南方的罗东晓海岸空气质量管理区表示，疏散区周围的污染物水平“完全正常”
美国环保署的哈里·艾伦表示，该机构于周五开始进行固定空气监测，部署了24台“全天候运行”的固定监测器
艾伦说，监测站没有观察到污染物，监测站将继续运行，直到现场安全为止。艾伦补充说，专业设备也已到位，以确保没有气体从事故源头的储罐中释放出来。
截至周日上午，疏散区周围空气中的污染物水平保持“完全正常”，艾伦说.
Authorities urgently try to stop California chemical tank explosion; 50,000 under evacuation orders
Authorities are urgently trying to stop an overheated, pressured and bulging tank filled with a toxic chemical from exploding in Orange County, California.
In what is being called an "unprecedented" situation, tens of thousands of people in the area were told to leave their homes Friday, with officials issuing a dire warning that the chemical tank, located at an aerospace facility, is in "crisis" and will either spill or explode.
"This is as real as it gets. It's the worst-case scenario I've ever faced in my career," Orange County Fire Authority (OCFA) Division Chief Craig Covey told ABC News on Saturday from the command center outside Garden Grove, teeming with first responders intent on preventing an environmental disaster.
Garden Grove is located about 30 miles south of Los Angeles.
In aSunday afternoon update, OCFA Interim Chief TJ McGovern said firefighters did "a recon mission on the tank" late Saturday during which they were able to visually inspect it.
"What they found was a potential crack in the tank, which could potentially be relieving some of the pressure in there," he said, adding that they were now "vetting and validating" the new information.
McGovern said they are confident that crack won't result in any leaks, but they are monitoring the air. He told ABC News that teams will conduct another mission on Sunday night to confirm information about the crack and, if the data is positive, they will likely decrease the size of the evacuation zone.
The OCFA said in asubsequent updatethat any areas outside of the evacuation zone "are currently considered completely safe and day-to-day activities can continue as normal."
"We continue to monitor the condition of the affected material and are working round the clock to mitigate the risk of a leak," a spokesperson for GKN Aerospace manufacturing company in Garden Grove, which is the tank's location, said in a statement to ABC News. "We are acutely aware of the uncertainty this incident is causing and sincerely apologize for the ongoing disruption to the local community."
The statement further said that GKN was working closely with local, state and federal agencies to address the situation.
"Our priority remains the safe resolution of this incident, so that residents can return to their homes as quickly as possible," the statement said.
On Saturday, California Gov. Gavin Newsom issued a state of emergency in Orange County in response to the incident.
"The safety of Orange County residents is the top priority," Newsom said in a statement Saturday. "We are mobilizing every state resource available to support local responders and make sure the community has what they need to stay safe."
On Sunday afternoon, Newsomsaidthat he had asked President Donald Trump to "issue an emergency declaration to support response operations in Orange County."
Looming over the roughly 10-square-mile evacuation zone now are both concerns that either toxic fumes could waft through the neighborhood, or that a dangerous fireball could erupt, according to an internal briefing memo reviewed by ABC News.
50,000 under evacuation orders
Mandatory evacuationshave expanded for the estimated 50,000 residents in the densely populated area, the memo said. There are multiple public facilities nearby -- including schools, hospitals, nursing homes, fire and law enforcement stations -- critical infrastructure, and essential services, all currently subject to mandatory evacuation and ongoing response operations.
Multiple roads have also been closed off in the evacuation zone, changing transportation routes in the area. Evacuation centers have been established across Garden Grove, Cypress, Stanton City Hall, Anaheim and Buena Park, the memo said.
Over a dozen schools have temporarily closed, and those adjacent to the evacuation area canceled outdoor activities "out of an abundance of caution," the Garden Grove Unified School District said.
Despite efforts overnight to cool down the tank, the temperature climbed from 77 degrees to 90. Covey confirmed the two scenarios that could play out: either a massive fireball erupts or the chemical leaks out, impacting the thousands of residents forced to evacuate.
Efforts to stop disaster: 'There's no precedent on this'
Asked about the timeline for when the situation could be resolved, Covey said: "We have no idea. Everybody asked me that question and I would love to give you an answer. There's no precedent on this. No one knows."
Officials are prepared for a potential chemical leak by diking, damming and diverting the flow of chemicals, which is the preferred option compared to an explosion -- but even that could prove to be complicated.
"If we burn down a bunch of buildings and a bunch of homes, that's a disaster," Covey said. 'But if we allow this to make it to the ocean and make it an ecological disaster, we don't want that as well."
How the situation unfolded
Firefighters initially responded to a leak at the GKN Aerospace manufacturing company in Garden Grove on Thursday, for vapor releasing from a 34,000-gallon tank containing methyl methacrylate, which is used in plastic manufacturing, according to the Orange County Fire Authority.
Authorities first issued an evacuation order on Thursday, but that was later lifted when vapor conditions improved. However, the evacuation orders were reissued and expanded on Friday due to what police called an "unprecedented" event.
On Friday, the situation had grown more dire, with officials warning that, though there was no active gas leak or plume, the tank was "actively in crisis" and unable to be secured.
Three tanks affected
Three tanks are affected at the GKN site, according to the internal briefing memo. Of most concern is Tank #1, which has the malfunctioning valve that, so far, is unable to be neutralized. That valve has seized due to the chemical reaction inside the container. Firefighters have been trying to get the temperature down and stable with water cooling.
Meanwhile, emergency responders on scene have been trying to troubleshoot Tank #2 -- which contains the same chemical as the other, compromised tank. Officials on scene have added a "neutralizer" to the methyl methacrylate in Tank #2 to prevent an even worse chain reaction. That tank appears to be structurally sound, the memo said.
Tank #4 is also structurally sound, however the status of what's inside it is "unknown."
Local fire and HAZMAT teams are on-site working to cool the 34,000-gallon industrial vessel and clean up, with investigation efforts underway, the memo said, with state emergency resources also partially activated. The EPA has also dispatched two on-scene coordinators to the facility.
The response remains active, and so far no injuries have been reported, the memo said.
Official: 'It fails or it blows up'
At a press briefing Friday, authorities laid out the urgency of the situation.
"There are literally two options left remaining: one, the tank fails and spills a total of about 6- to 7,000 gallons of very bad chemicals into the parking lot in that area. Or two, the tank goes into a thermal runaway and blows up, affecting the tanks that are around them that have fuel or the chemicals in them as well," Covey said in avideo updateFriday.
He added, "We are setting up these evacuations in preparation for these two options -- it fails or it blows up," he said.
Officials have said it is unclear when residents will be able to return to their homes.
"This is highly volatile, it's highly toxic, it's highly flammable," Covey said during an earlier press briefing, while urging people to evacuate. "This is not precautionary. This is gonna happen unless some brilliant guy behind me here figures out how we can mitigate this incident. This thing is gonna fail -- we don't know when."
What is methyl methacrylate?
Methyl methacrylate is an industrial chemical used in plastics and manufacturing and is primarily a respiratory irritant, authorities said. Around 7,000 gallons are estimated to be left in the tank that's in crisis, Covey said.
Short-term exposure to the chemical can cause skin and eye irritation, as well as breathing problems, according to the EPA.
Orange County Health Officer Regina Chinsio-Kwong said in a video update Friday evening that an explosion could cause the chemical to be released as a vapor, which, if inhaled, could cause "severe respiratory issues." Other symptoms include a sore throat, runny nose, itchy and burning eyes, and potentially nausea and headache, she said.
GKN Aerospace builds engines and landing gear for both commercial and military aircraft. ABC News has reached out for comment.
In a video posted to the Orange County Fire Authority's X account, Jason Lo of the SouthCoast Air Quality Management District said that levels of pollutants around the evacuation zone were "completely normal."
Harry Allen of the EPA said the agency began stationary air monitoring on Friday, deploying 24 stationary monitors that are "operating around the clock."
No contaminants have been observed by the monitoring stations, which will continue to operate until the scene is secure, Allen said. Specialty equipment is also in place to ensure that no gas is released from the tank at the source of the incident, Allen added.
Pollutant levels in the air around the evacuation zone remained "completely normal" as of Sunday morning,Allen said.
