The Costa Rica Agriculture and Livestock Ministry (MAG) recommended on Wednesday that farmers who own land within a three kilometer radius of the crater of the Turrialba volcano check their crops for acid rain damage.

The rain, which has been falling for several years around the volcano, could intensify in density and range as toxic gases begin to seep out of the mountain.

Francisco Brenes, Cartago's regional MAG director, encouraged farmers to buy instruments that measure pH levels in morning dews, waterways and rainfalls. Since crops have different acidity tolerances, farmers should check crop requirements and capacities in order to gauge how much acid is harmful for their yields.

Officials also recommended that farmers wash ash off of their plants to prevent diseases and allow the leaves to breathe.

Eliécer Duarte, a scientist with the Volcanological and Seismological Observatory of Costa Rica (OVSICORI), said that acid rain is “nothing new” in Turrialba. The observatory began documenting acid rain in the area as far back as 2002. He noted that in 2007 and 2008 the region experienced a peak in acid rainfall levels and yields were mildly affected.

The ash and gases that have begun to seep out of the volcano since it began spewing particles in early January, he said, “could increase the amount of acid rain and effect even more that the zone that has already been affected.”