brominated pools and skin irritation

Buyer Beware! 
Complaints of irritated skin are much more common in brominated than chlorinated pools.

A small, but increasing number of pools, are being disinfected with a solid brominated compound (1-bromo-3-chloro-5,5-dimethyl-hydantoin) or “1355”.  Di-halo and Aquabrome are two of the many trade names for 1355.

 Typical Findings:

  • A large pool was changed from chlorine gas to 1355.  One month later a 32 year old male attendant developed itchy, red skin after being in the pool.  Eczema subsequently erupted on his hands and body.  It improved away from work and relapsed rapidly on return.  He could swim without symptoms in a chlorinated pool, but a rescue dive into the brominated pool resulted in itchy, red eruptions within 20 minutes.  Patch tests using 1% 1355 in water and 1% 1355 in petrolatum were negative.  No reactions occurred in 8 other symptomatic patients who were patch-tested with 1355.
  • A 40 year-old swimming instructor presented a similar picture.  Her rash cleared when the pool changed to using a solid chorine disinfectant (dichlorisocyanurate) but relapsed when she began to work in another pool treated with 1355.  
  • Visits to 19 pools indicated many staff members are affected.  This suggests that frequent exposure is relevant. Older age groups are affected much more than children. 
  • Surveys have been made among readers of pool industry magazines.  70 people had suffered more than trivial rashes - soreness of mouth, throat, vulva, female urethra, breasts.  65 of the 70 were associated with pools treated with 1355.  58 of these 65 reacted within 12 hours of swimming.  None was affected by chlorinated pools.

1355 dissolves in water and releases bromine, chlorine and 5,5-dimethyl-hydantoin (dmh).  Further reactions of these chemicals with pool contaminants such as urea and creatinine and numerous organics produce products which include bromamines, chloramines and innumerable complex organic compounds containing bromine and chlorine.  Manufacturers’ data on 1355 toxicity and the results of skin patch and prick tests indicate that direct allergy to 1355 or DMH is unlikely.  Infection is also unlikely because pools having the highest total bromine residuals [as measured using the reagent diethyl-p-phenylenediamine (DPD)], and therefore the lowest bacterial contamination, had higher incidents of skin irritation. 

Although the precise irritants have not been (and may never be) identified, there is strong circumstantial evidence that 1355 reacts with chemicals common in swimming pools to form compounds which irritate the skin of many people.

Richard Kunz, chemist
719 635-1325