Those that are infrequently opened and/or contain sewer traps are likely to accumulate carbon dioxide and become oxygen deficient.
(Those; are infrequently opened; ) (Those; contain; sewer traps) (Those that are infrequently opened and/or contain sewer traps; are; likely to accumulate carbon dioxide and become oxygen deficient) (Those that are infrequently opened and/or contain sewer traps; to accumulate; carbon dioxide) (Those that are infrequently opened and/or contain sewer traps; to become; oxygen deficient)
Those Those Those that are infrequently opened and/or contain sewer traps Those that are infrequently opened and/or contain sewer traps Those that are infrequently opened and/or contain sewer traps
are infrequently opened contain are to accumulate to become
sewer traps
likely to accumulate carbon dioxide and become oxygen deficient
carbon dioxide
oxygen deficient