Question: Why did Walt change his production method in season 1?
About the article "Breaking Bad", section "Scientific accuracy".

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Lydia Rodarte-Quayle (played by Laura Fraser) is an executive of Madrigal Electromotive GmbH, working out of the company's office in Houston, Texas.
Along with Jack and Todd, she serves as one of the antagonists of the final season.
She appears to be nervous most of the time and acts aloof, regularly ordering chamomile tea with soy milk and the sweetener stevia.
She helped Gus Fring distribute drugs throughout the American southwest.
When the D.E.A.
begins investigating the link between Gus and Madrigal, Lydia becomes anxious and asks Mike to eliminate eleven people who were involved with Gus.
When he refuses, Lydia makes the same offer to one of the eleven on her hit list and adds Mike to those she wants killed.
However, Mike deduces her plan and dispatches the new hit man, but not before Chow is killed.
Mike breaks into Lydia's home, ready to execute her, but allows her to live contingent on her providing him with methylamine.
After Lydia provides the first shipment, the D.E.A.
visits Madrigal and Lydia is forced to give up her guy in the warehouse to the D.E.A.
Mike sends Jesse to Houston to pick up the methylamine, and he and Lydia find a GPS tracker at the bottom of one of the barrels.
Mike later deduces that Lydia placed it, because she wants out of the business.
Mike again vows to kill her.
Jesse, not wanting her to die, tries to intervene on the pretense that maybe the D.E.A.
did plant the tracker.
Walt sides with Jesse because he refuses to cease making meth.
After bugging Hank's office, they force her to call him and ask about the device.
Hank tells her his office did not plant any tracker, and the three are about to kill her until they hear the D.E.A.
's Houston office telling Hank that they placed trackers on every barrel, through the bug.
In an effort to save herself, Lydia provides Walt, Jesse, and Mike information about a freight train that carries "an ocean of methylamine".
Later, she provides Walt with a new market in the Czech Republic, using her resources and network to distribute the meth in large quantities.
After Walt quits, and Declan and his gang are massacred, Todd becomes Lydia's cook.
During a meeting with Todd, Walt interrupts and offers to provide a new method of meth production.
Lydia appears to agree to Walt's offer, but suggests to Todd after Walt leaves that Walt should be killed at the meeting.
As their meeting continues, Lydia adds stevia to her tea, which Walt had replaced with ricin.
That evening Lydia, showing the flu-like symptoms characteristic of ricin poisoning, calls Todd to check on whether the gang followed through on killing Walt.
A gloating Walter answers and tells her that the entire gang is dead, and that she has been poisoned before he hangs up on a horrified Lydia. 
Season five.
Part 1.
Walt's defeat of Gus leads him to develop a sense of arrogance and invulnerability.
He and Jesse join forces with Mike to establish their own meth operation.
While searching for new locations to cook, Walt devises a plan to periodically set up his lab in residential houses tented by a pest control business.
Trouble with their supplier leaves Walter, Jesse and Mike without any methylamine precursor.
Mike suggests ramping down production, but Walt insists they stay on course.
Their new supplier, Lydia, is an executive for Madrigal Electromotive GmbH, the parent company of Los Pollos Hermanos and the supplier of Gus's methylamine.
Skyler attempts to send the kids away from home, afraid of what Walt's meth business might bring upon them.
During a dinner with Hank and Marie, she stages a suicide attempt in an effort to convince the Schraders to temporarily take custody of Walt Jr. and Holly.
With the children gone, she tells Walt that she'll keep fighting him until he finally dies of cancer.
Lydia assists Walt, Mike, and Jesse to steal a thousand gallons of Madrigal's methylamine from a train traveling through New Mexico.
A fourth member of their gang, Todd, kills a young boy who witnesses the heist.
After disposing of both the boy and his dirt bike with hydrofluoric acid, Mike and Jesse move to end the partnership and sell the methylamine to a Phoenix-based competitor named Declan.
Even though Declan initially wants Walt's meth pulled off the drug market, Walt persuades him to sell his superior product.
Walt argues with Jesse over his leaving their meth operation, and learns that the DEA is poised to arrest Mike after flipping his lawyer.
During an angry confrontation with Mike, Walt impulsively kills him.
He then conspires with Todd's uncle, Jack, to have the witnesses and their lawyer killed during a mass assassination.
Walt also makes a deal with Lydia to begin distributing his product overseas in the Czech Republic.
After a few months, he amasses so much money that Skyler cannot even count it all.
Walt reluctantly decides to end his involvement in the meth business, and his family is reunited.
During a family gathering at the White residence, Hank goes to the bathroom and discovers Walt's copy of "Leaves of Grass" given to him by Gale, which contains a handwritten note addressing Walt as "my other favorite W.W." Remembering a conversation he previously had with Walt regarding those initials in Gale's lab notebook, Hank realizes that Walt has been Heisenberg all along. 
The 2013 Walt Disney World Pro Soccer Classic was the fourth edition of the Walt Disney World Pro Soccer Classic, a pre-season exhibition tournament held at the ESPN Wide World of Sports Complex at the Walt Disney World Resort in Lake Buena Vista, Florida.
A total of six Major League Soccer teams participated.
The defending champions were the Vancouver Whitecaps FC.
The club did not participate in the 2013 tournament.
The Houston Dynamo and FC Dallas did not compete for the first time since the competition's inception in 2010.
Toronto is the last original team.
The tournament was won by the Montreal Impact, who defeated the Columbus Crew by a 1–0 score line. 
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He stated, "We did not get the following 26 episodes."
When asked why the series lost its bid for more episodes, Hill responded, "There weren't enough viewers."
Currently, a petition is being signed to continue the series. 
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The serial starred Mouseketeer Annette Funicello and Sammy Ogg of Spin and Marty and featured Kevin Corcoran in his first Walt Disney production.