On March 20, 2019, the EPA released lists of the next 20 high-priority and 20 low-priority existing chemicals that are candidates for TSCA risk evaluations. The Agency released this list to provide the public an opportunity to submit relevant information over the next 90 days, such as the uses, hazards, and exposure for these chemicals. Publication also activates a statutory requirement for EPA to complete the prioritization process in the next 9 to 12 months, allowing EPA to designate 20 chemicals as high priority and 20 chemicals as low priority by December 2019. According to EPA and TSCA, when prioritization is complete, chemicals designated as high priority will begin a 3-year risk evaluation process to determine whether each chemical, under the conditions of use, presents an unreasonable risk to human health and the environment. The designation of a chemical as a low priority means that further risk evaluation is not warranted at this time.
Based on our review, it appears that all 20 high-priority chemicals are from the 2014 Update of the TSCA Work Plan. TSCA requires that at least 50 percent of all high-priority chemicals be from the Work Plan. For this round, EPA has used 100 percent from the Work Plan list. The low-priority chemicals all are from EPA’s Safer Chemicals Ingredients List (SCIL).
TSCA also requires that EPA give preference to Work Plan chemicals with the following characteristics:
- Persistence and bioaccumulation scores of three
- Known human carcinogens
- High acute or chronic toxicity
ToxStrategies has examined the TSCA Work Plan and has the following observations:
- None of the selected high-priority chemicals have persistence and bioaccumulation scores of three. In fact, eight of the 20 candidates have persistence and bioaccumulation scores of one, particularly the phthalates, which are selected based on aquatic toxicity but have low persistence and low bioaccumulation potential.
- None of the selected high-priority chemicals are from the seven substances that scored 3 on all three criteria (hazard, exposure, persistence/bioaccumulation) and remain in the TSCA Work Plan after eliminating the first 10 already being evaluated. This includes four metals; no metals have been selected to date.
- TSCA Work Plan scores for the 20 high-priority candidates are summarized below.
| HIGH-PRIORITY CANDIDATE | HAZARD Score | EXPOSURE Score | PERSISTENCE BIOACCUMULATION Score |
|---|---|---|---|
| p-dichlorobenzene | 3 possible carcinogen |
3 wide consumer use |
2 moderate P, low B |
| 1,2-dichloroethane | 3 possible carcinogen |
3 wide consumer use |
2 moderate P, low B |
| trans-1,2- dichloroethylene | 2 chronic toxicity | 3 wide consumer use |
2 moderate P, low B |
| o-dichlorobenzene | 2 chronic toxicity | 3 wide consumer use |
2 moderate P, low B |
| 1,1,2-trichloroethane | 3 possible carcinogen |
2 consumer use | 2 high P, low B |
| 1,2-dichloropropane | 2 Acute mammalian toxicity |
3 wide consumer use |
2 high P, low B |
| 1,1-dichloroethane | 2 mutagenetic | 3 wide consumer use |
2 moderate P, low B |
| Dibutyl phthalate | 3 chronic aquatic toxicity |
3 wide consumer use |
1 low P, low B |
| Butyl benzyl phthalate | 3 chronic aquatic toxicity |
3 wide consumer use |
1 low P,low B |
| di-ethylhexyl phthalate | 3 chronic aquatic toxicity |
3 wide consumer use |
1 low P, low B |
| di-isobutyl phthalate | 1 reproductive toxicity | 2 specialty use | 1 low P, low B |
| dicyclohexyl phthalate | 3 chronic aquatic toxicity |
3 plasticizer and heat sealer |
1 low P, low B |
| TBBPA | 2 acute aquatic toxicity |
3 wide use as circuit board flame retardant |
2 high P, low B |
| TCEP | 2 mutagenic | 2 consumer use | 2 moderate P, low B |
| phosphoric acid triphenyl ester | 3 Acute and chronic aquatic toxicity |
3 wide use as circuit board flame retardant |
2 moderate P, moderate B |
| ethylene dibromide | 3 probable carcinogen |
2 commercial/industrial use | 2 moderate P, low B |
| 1,3-butadiene | 3 known carcinogen |
3 major petrochemical commodity |
1 low P, low B |
| HHCB | 2 developmental toxicity | 3 wide consumer use |
2 moderate P, moderate B |
| formaldehyde | 3 known carcinogen |
3 wide consumer use |
1 low P, low B |
| phthalic anhydride | 3 respiratory sensitizer | 3 wide consumer use |
1 low P, low B |