the family stayed had been fumigated with methyl bromide .
esmond has regained story highlights chemical damages ozone and is being phased out , though it 's used in strawberry fields , epa says a delaware family becomes ill at a resort in the u.s. virgin islands preliminary epa results find methyl bromide was present in the unit where they stayed ( cnn ) a delaware father is in stable condition and improving as his two boys remain in critical condition after they became sick -- perhaps from pesticide exposure , federal officials say -- during a trip to the u.s. virgin islands .
the epa was notified on march 20 that the family was hospitalized after a fumigation days earlier at sirenusa resort in cruz bay , st. john .
an epa spokeswoman said thursday that the chemical was also used in other units in october 2014 .
u.s. environmental protection agency officials said the agency is looking into the use of the pesticide methyl bromide at the sirenusa condominium resort in cruz bay , st. john .
the u.s. environmental protection agency said tuesday that investigators found the toxic chemical has been used there other times before .
steve esmond , his teenage sons and the teens ' mother fell ill more than two weeks ago in st. john , where they were renting a villa at the sirenusa resort .
a family spokesman said steve esmond , his wife , theresa devine , and their two teenage sons were airlifted to hospitals on the u.s. mainland .
initially , the epa , which also holds authority over the u.s. virgin islands .