UPDATE 12:45 p.m.: Tim Yaeger, emergency coordinator, just informed dispatch that the leak was closed 7 minutes ago.

Original report continues below ...

A "major" ammonia leak has been reported at Torrey Farms, 7170 Norton Road and hazmat has been dispatched.

A first-responder said, "Two valves on this tank that need to be shut off, but no way can we get near it."

He also reported it's a 15 ton cylinder "just going wild."

The wind is 16 m.p.h. out of the east. 

Norton Road has been closed.

UPDATE 11:55 a.m.  There's no new information at this time. Emergency teams are on scene. No report yet on the status of the leak. No indication of the situation getting worse.

UPDATE:  The media isn't being let into the scene, which isn't surprising. I'm not planning on going out there unless and until there is a press conference.

UPDATE: Here's what the State's health department site says about Ammonia:

How is ammonia used?
About 80% of the ammonia produced by industry is used in agriculture as fertilizer. Ammonia is also used as a refrigerant gas, for purification of water supplies, and in the manufacture of plastics, explosives, textiles, pesticides, dyes and other chemicals. It is found in many household and industrial-strength cleaning solutions. Household ammonia cleaning solutions are manufactured by adding ammonia gas to water and can be between 5 and 10% ammonia. Ammonia solutions for industrial use may be concentrations of 25% or higher and are corrosive.

How can people be exposed to ammonia?
Most people are exposed to ammonia from inhalation of the gas or vapors. Since ammonia exists naturally and is also present in cleaning products, exposure may occur from these sources. The widespread use of ammonia on farms and in industrial and commercial locations also means that exposure can occur from an accidental release or from a deliberate terrorist attack.

Anhydrous ammonia gas is lighter than air and will rise, so that generally it dissipates and does not settle in low-lying areas. However, in the presence of moisture (such as high relative humidity), the liquefied anhydrous ammonia gas forms vapors that are heavier than air. These vapors may spread along the ground or into low-lying areas with poor airflow where people may become exposed.

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