Dichlorvos chemical review

In December 1994 dichlorvos was nominated for review as part of the Existing Chemicals Review Program, which was established to systematically review a number of Agvet chemicals that had been on the Australian market for some time.

In December 1996 the APVMA began a review of dichlorvos because of concerns relating to public and occupational health and safety, the environment, residues and trade. This action was based on reports of adverse experiences, regulatory action by the United States Environmental Protection Agency, and residue violations in cereals and cereal products.

In 2000 the APVMA released the dichlorvos draft report, which contained component assessment reports for agriculture, efficacy, residues, trade, environment, chemistry, toxicology and occupational health and safety. These documents are not available electronically.

In 2008 the APVMA released the dichlorvos draft (preliminary review findings) report, which contained the component assessment report for residues, with separate component assessment reports for toxicology, occupational health and safety and environment.

In 2013 the APVMA also released a summary of the occupational health and safety interim assessment report (dichlorvos interim regulatory restrictions). This outlined the reasons behind the interim restrictions placed on the use of dichlorvos for grain protection use while further occupational health and safety data was to be generated to allow the review to be finalised.

In 2000, the APVMA released the dichlorvos draft report.

We determined that:

• there were significant occupational health and safety and residue data gaps for some uses of dichlorvos
• the existing data were inadequate to establish or maintain maximum residue limits (MRLs)
• the use of dichlorvos might pose a potential risk to birds, bees, fish and invertebrate aquatic organisms
• there was a potential risk to workers from some dichlorvos application methods
• product labels did not contain adequate instructions or warnings for the safe use of dichlorvos.

The APVMA requested more information from registrants on occupational health and safety and on residue levels to assess any potential risks from the use of dichlorvos.

In the preliminary report we proposed:

• varying product labels to include stronger first aid and safety directions and warnings to minimise the exposure of humans, birds, bees and aquatic organisms
• increasing withholding periods for grain (seven days for grain treated at six parts per million and 28 days for grain treated at 12 parts per million)
• setting temporary MRLs for a number of commodities until further residue data were generated. These include cocoa beans, coffee beans, edible meat and offal (mammalian), eggs, fruits, milks, mushrooms, peanuts, poultry meat and offal, tomatoes and tree nuts and vegetables
• setting an MRL for rice hulls of 50 milligram per kilogram.

The APVMA noted that the Office of Chemical Safety recommended an increase in the acceptable daily intake for dichlorvos from 0.0005 to 0.001 milligrams per kilogram of body weight per day. This is based on a no-observable-effect level for plasma cholinesterase inhibition of 0.013 milligrams per kilogram of body weight per day in human volunteers in a 28-day oral administration study, and using a 10-fold safety factor (to account for variability in human sensitivity).

In 2008 we released the preliminary review findings report for dichlorvos, after receiving additional toxicological information and exposure studies as well as comments after the publication of the draft report. After assessing the new data, the Office of Chemical Safety revised the acute reference dose (ARfD) for dichlorvos. Consequently, both the occupational health and safety assessment in the occupational health and safety component report and the acute dietary risk assessment in the residues component report were revised. The 2008 report included component assessment reports for residues, toxicology, occupational health and safety and the environment.

Public consultations have been conducted following the publication of the dichlorvos draft report in 2000 and the publication of the Dichlorvos preliminary review findings report in 2008.

In March 2011 the APVMA published a report entitled The reconsideration of the active constituent dichlorvos, registrations of products containing dichlorvos and approvals of their associated labels. This report summarised toxicological assessment and risk assessments with respect to the environment, public health, occupational health and safety and Australian trade with other countries. It also outlined the regulatory decisions of the dichlorvos review.

We determined that there was insufficient data for us to be satisfied that there was adequate protection for people in relation to occupational exposure, exposure arising from some domestic uses, and residues in some food commodities. We also determined that the safety directions on dichlorvos product labels did not conform to current safety standards and that labels did not contain adequate information to protect the environment.

Accordingly, the APVMA cancelled the registration of one home garden product, cancelled some specific uses (including use for grain fumigation) and required registrants to modify products labels in line with the review findings.

In August 2012, the APVMA was made aware that dichlorvos products continue to be supplied into the marketplace accompanied by instructions for use that do not comply with the findings of the dichlorvos review.

In March 2013, we suspended the use of six dichlorvos products based on their potential risk to worker occupational health and safety, and published a summary report outlining the work that led to this suspension action. The suspension has since encompassed one more product, but released one product that complies with the regulatory decision of 2011.

In February 2014, the suspension period was extended for an additional 12 months, as the concerns that formed the basis of the original suspension of label approvals and product registrations have not altered for these products.

In January 2015, we took action to remove the grain protection use from suspended product labels as our concerns had not been addressed. This resulted in the cancellation of registrations of the two 1140 EC products, the cancellation of one 500 EC product, and the variation of the remaining product labels, which now can only be used to control European wasps.

The phase out for the grain protection use will run to 2 March 2015 to coincide with the expiry of the suspension permit PER14075, and the end of the 2014-15 grain harvest season to enable growers to use any remaining stocks of dichlorvos.