Ijen crater lake got closed as from last evening at around 22:00, 21 March 2018. Gas emissions by the lake increased to such a level that hundreds if residents in two plantation areas on the slopes of mount Ijen fled to saver grounds.

According to residents the smell of sulphur gas appeared approximately at 19:00 last night. The smell grew stronger and caused dozens of people to faint.
Dozens of unconscious citizens were evacuated to community health centers (source: detikNews).

Catimor Homestay can be reached 

Volcanology closed the area. But Catimor Homestay at a distance of 17 km fro Paltuding can still be reached via Bondowoso. But from the homestay the road to Paltuding is closed. Paltuding is the post from where your hike to the lake starts. It is a hike of about 3.3 km. The area will be closed till further notice. We will keep you posted.

Toxic reactions - a little background information

Small eruptions inside the crater release toxic gases sulphur dioxide (SO2), carbon dioxide (CO2), and sulfuric acid (H2S). This release of toxic gasses is related to the water level - mainly due to rainfall - and the water temperature at several depths of the lake and small explosions that release these toxic gasses.