UPDATE (6/21): The Mercedes dome is now open and in use.

At least 300 people were taken from the dome to the fire department and other area shelters due to flooding.

The mayor tells us he plans to make improvements in the drainage around the facility to prevent flooding in the future.

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MERCEDES - Residents in Mercedes are unsure of where to seek shelter after learning the city's emergency dome is unsafe. 

The shelter was tested for the first time in two years but did not make the cut.

Officials have re-routed those who were already at the dome to other Rio Grande Valley cities, such as Weslaco and Donna.

A CHANNEL 5 NEWS crew spent hours trying to find a way into the shelter, but the route proved to be unsafe as well. 

KRGV's Sierra Pizarro spoke with the mayor of Mercedes about the facility's current conditions.

Watch the video above for the full story.