 -- The Environmental Protection Agency says it is now investigating a massive ongoing natural gas leak in Los Angeles' Porter Ranch neighborhood that's being called one of the worst environmental disasters in years.

More than two months after the leak started, methane gas continues to escape from an underground pipe at Southern California Gas Company's Aliso Canyon facility. SoCal Gas acknowledged early in December that a leak had been detected at a natural gas storage well on Oct. 23, but said "experts agree that natural gas is not toxic."

Thousands of residents, however, said the gas smell -- stemming from an odorous additive called mercaptan used to signal a leak -- made them feel sick, bringing on headaches, dizziness and nausea.

"We're devastated," resident David Balen told KABC-TV. "Our community has been shaken up. Our schools have been shaken up. People have been relocated.”

According to KABC-TV, SoCal Gas had helped place more than 2,200 families. The situation even drew the attention of celebrity Leonardo DiCaprio, an environmental campaigner. Methane can contribute to climate change.

The EPA said in a letter responding to a request by US Rep. Brad Sherman's for involvement, that it had dispatched two on-scene coordinators to SoCal Gas' Aliso Canyon facility. The US agency also said that daily communications continued with local and state officials "to stay abreast of developments in controlling the gas and assisting local residents."

The EPA also said that it had sent an information request to SoCal Gas on Dec. 18. On Monday, SoCal Gas officials said they'd found the location of the leak. Officials said Monday that after careful drilling, they were in the process of fixing the leak but that it could take until late February.

"It's very scary and you know don't know what the long-term effects are going to be," resident Laurie Cherny said. "But, you know. We do our best."