A massive fire just came back to life, and now Los Angeles can't breathe.

A warehouse fire in Boyle Heights is out of control again, sending toxic smoke across the city and forcing families to lock themselves inside.

Imagine waking up to a sky so thick with smoke you cannot see the street. Every breath you take feels heavy and dangerous.

This is the reality for thousands of people in Los Angeles right now. A huge fire at a warehouse in Boyle Heights started up again on Saturday.

WHAT HAPPENED

Firefighters say the flames are growing out of control. The fire is burning through factory materials inside the large building.

Thick, black smoke is spreading to many neighborhoods. It is making it very hard for drivers to see on the big roads nearby.

City leaders sent out an urgent warning to everyone in the area. They say you must stay inside and keep your windows and doors shut tight.

What the evidence shows

• The fire is burning in the Boyle Heights area of the city.
• Fire crews say the blaze is currently out of control.
• Smoke has covered several neighborhoods and blocked views on main roads.
• Health officials issued an urgent warning about the air quality.
• Residents are told to stay indoors to avoid breathing the smoke.

THE BIGGER QUESTION

We often think that once a fire is out, the danger is over. But when a fire this big comes back to life, it makes us wonder if our city is truly ready for these kinds of accidents.

Are these old buildings safe enough for the people who live next to them? This story shows how one fire can change the lives of thousands in just a few minutes.

THE OTHER SIDE

Owners of large buildings are required to follow strict safety rules to prevent fires. We do not yet know if the building had the right tools to stop a fire from spreading or starting again.

Right now, there is no proof that the owners did anything wrong, but the investigation is just starting.

WHAT HAPPENS NOW

Families in the path of the smoke will have to stay inside until the air is clear. This could take a long time if the wind does not help.

Fire crews are still working hard to stop the flames from spreading to other buildings. Traffic will likely be a mess for the rest of the weekend.

WHAT WE STILL DON'T KNOW

1. What specific items were being kept inside the warehouse?
2. Why did the fire start back up after it seemed to be over?
3. How long will the air stay dangerous for local children and seniors?

SOURCE NOTE

Based on reporting from the New York Post. All charges are allegations - any named parties are presumed innocent until proven guilty.